summaryrefslogtreecommitdiffstats
path: root/io_uring/io_uring.c
blob: d3926a27714e2afd0b61940b78157e401a91886c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
859
860
861
862
863
864
865
866
867
868
869
870
871
872
873
874
875
876
877
878
879
880
881
882
883
884
885
886
887
888
889
890
891
892
893
894
895
896
897
898
899
900
901
902
903
904
905
906
907
908
909
910
911
912
913
914
915
916
917
918
919
920
921
922
923
924
925
926
927
928
929
930
931
932
933
934
935
936
937
938
939
940
941
942
943
944
945
946
947
948
949
950
951
952
953
954
955
956
957
958
959
960
961
962
963
964
965
966
967
968
969
970
971
972
973
974
975
976
977
978
979
980
981
982
983
984
985
986
987
988
989
990
991
992
993
994
995
996
997
998
999
1000
1001
1002
1003
1004
1005
1006
1007
1008
1009
1010
1011
1012
1013
1014
1015
1016
1017
1018
1019
1020
1021
1022
1023
1024
1025
1026
1027
1028
1029
1030
1031
1032
1033
1034
1035
1036
1037
1038
1039
1040
1041
1042
1043
1044
1045
1046
1047
1048
1049
1050
1051
1052
1053
1054
1055
1056
1057
1058
1059
1060
1061
1062
1063
1064
1065
1066
1067
1068
1069
1070
1071
1072
1073
1074
1075
1076
1077
1078
1079
1080
1081
1082
1083
1084
1085
1086
1087
1088
1089
1090
1091
1092
1093
1094
1095
1096
1097
1098
1099
1100
1101
1102
1103
1104
1105
1106
1107
1108
1109
1110
1111
1112
1113
1114
1115
1116
1117
1118
1119
1120
1121
1122
1123
1124
1125
1126
1127
1128
1129
1130
1131
1132
1133
1134
1135
1136
1137
1138
1139
1140
1141
1142
1143
1144
1145
1146
1147
1148
1149
1150
1151
1152
1153
1154
1155
1156
1157
1158
1159
1160
1161
1162
1163
1164
1165
1166
1167
1168
1169
1170
1171
1172
1173
1174
1175
1176
1177
1178
1179
1180
1181
1182
1183
1184
1185
1186
1187
1188
1189
1190
1191
1192
1193
1194
1195
1196
1197
1198
1199
1200
1201
1202
1203
1204
1205
1206
1207
1208
1209
1210
1211
1212
1213
1214
1215
1216
1217
1218
1219
1220
1221
1222
1223
1224
1225
1226
1227
1228
1229
1230
1231
1232
1233
1234
1235
1236
1237
1238
1239
1240
1241
1242
1243
1244
1245
1246
1247
1248
1249
1250
1251
1252
1253
1254
1255
1256
1257
1258
1259
1260
1261
1262
1263
1264
1265
1266
1267
1268
1269
1270
1271
1272
1273
1274
1275
1276
1277
1278
1279
1280
1281
1282
1283
1284
1285
1286
1287
1288
1289
1290
1291
1292
1293
1294
1295
1296
1297
1298
1299
1300
1301
1302
1303
1304
1305
1306
1307
1308
1309
1310
1311
1312
1313
1314
1315
1316
1317
1318
1319
1320
1321
1322
1323
1324
1325
1326
1327
1328
1329
1330
1331
1332
1333
1334
1335
1336
1337
1338
1339
1340
1341
1342
1343
1344
1345
1346
1347
1348
1349
1350
1351
1352
1353
1354
1355
1356
1357
1358
1359
1360
1361
1362
1363
1364
1365
1366
1367
1368
1369
1370
1371
1372
1373
1374
1375
1376
1377
1378
1379
1380
1381
1382
1383
1384
1385
1386
1387
1388
1389
1390
1391
1392
1393
1394
1395
1396
1397
1398
1399
1400
1401
1402
1403
1404
1405
1406
1407
1408
1409
1410
1411
1412
1413
1414
1415
1416
1417
1418
1419
1420
1421
1422
1423
1424
1425
1426
1427
1428
1429
1430
1431
1432
1433
1434
1435
1436
1437
1438
1439
1440
1441
1442
1443
1444
1445
1446
1447
1448
1449
1450
1451
1452
1453
1454
1455
1456
1457
1458
1459
1460
1461
1462
1463
1464
1465
1466
1467
1468
1469
1470
1471
1472
1473
1474
1475
1476
1477
1478
1479
1480
1481
1482
1483
1484
1485
1486
1487
1488
1489
1490
1491
1492
1493
1494
1495
1496
1497
1498
1499
1500
1501
1502
1503
1504
1505
1506
1507
1508
1509
1510
1511
1512
1513
1514
1515
1516
1517
1518
1519
1520
1521
1522
1523
1524
1525
1526
1527
1528
1529
1530
1531
1532
1533
1534
1535
1536
1537
1538
1539
1540
1541
1542
1543
1544
1545
1546
1547
1548
1549
1550
1551
1552
1553
1554
1555
1556
1557
1558
1559
1560
1561
1562
1563
1564
1565
1566
1567
1568
1569
1570
1571
1572
1573
1574
1575
1576
1577
1578
1579
1580
1581
1582
1583
1584
1585
1586
1587
1588
1589
1590
1591
1592
1593
1594
1595
1596
1597
1598
1599
1600
1601
1602
1603
1604
1605
1606
1607
1608
1609
1610
1611
1612
1613
1614
1615
1616
1617
1618
1619
1620
1621
1622
1623
1624
1625
1626
1627
1628
1629
1630
1631
1632
1633
1634
1635
1636
1637
1638
1639
1640
1641
1642
1643
1644
1645
1646
1647
1648
1649
1650
1651
1652
1653
1654
1655
1656
1657
1658
1659
1660
1661
1662
1663
1664
1665
1666
1667
1668
1669
1670
1671
1672
1673
1674
1675
1676
1677
1678
1679
1680
1681
1682
1683
1684
1685
1686
1687
1688
1689
1690
1691
1692
1693
1694
1695
1696
1697
1698
1699
1700
1701
1702
1703
1704
1705
1706
1707
1708
1709
1710
1711
1712
1713
1714
1715
1716
1717
1718
1719
1720
1721
1722
1723
1724
1725
1726
1727
1728
1729
1730
1731
1732
1733
1734
1735
1736
1737
1738
1739
1740
1741
1742
1743
1744
1745
1746
1747
1748
1749
1750
1751
1752
1753
1754
1755
1756
1757
1758
1759
1760
1761
1762
1763
1764
1765
1766
1767
1768
1769
1770
1771
1772
1773
1774
1775
1776
1777
1778
1779
1780
1781
1782
1783
1784
1785
1786
1787
1788
1789
1790
1791
1792
1793
1794
1795
1796
1797
1798
1799
1800
1801
1802
1803
1804
1805
1806
1807
1808
1809
1810
1811
1812
1813
1814
1815
1816
1817
1818
1819
1820
1821
1822
1823
1824
1825
1826
1827
1828
1829
1830
1831
1832
1833
1834
1835
1836
1837
1838
1839
1840
1841
1842
1843
1844
1845
1846
1847
1848
1849
1850
1851
1852
1853
1854
1855
1856
1857
1858
1859
1860
1861
1862
1863
1864
1865
1866
1867
1868
1869
1870
1871
1872
1873
1874
1875
1876
1877
1878
1879
1880
1881
1882
1883
1884
1885
1886
1887
1888
1889
1890
1891
1892
1893
1894
1895
1896
1897
1898
1899
1900
1901
1902
1903
1904
1905
1906
1907
1908
1909
1910
1911
1912
1913
1914
1915
1916
1917
1918
1919
1920
1921
1922
1923
1924
1925
1926
1927
1928
1929
1930
1931
1932
1933
1934
1935
1936
1937
1938
1939
1940
1941
1942
1943
1944
1945
1946
1947
1948
1949
1950
1951
1952
1953
1954
1955
1956
1957
1958
1959
1960
1961
1962
1963
1964
1965
1966
1967
1968
1969
1970
1971
1972
1973
1974
1975
1976
1977
1978
1979
1980
1981
1982
1983
1984
1985
1986
1987
1988
1989
1990
1991
1992
1993
1994
1995
1996
1997
1998
1999
2000
2001
2002
2003
2004
2005
2006
2007
2008
2009
2010
2011
2012
2013
2014
2015
2016
2017
2018
2019
2020
2021
2022
2023
2024
2025
2026
2027
2028
2029
2030
2031
2032
2033
2034
2035
2036
2037
2038
2039
2040
2041
2042
2043
2044
2045
2046
2047
2048
2049
2050
2051
2052
2053
2054
2055
2056
2057
2058
2059
2060
2061
2062
2063
2064
2065
2066
2067
2068
2069
2070
2071
2072
2073
2074
2075
2076
2077
2078
2079
2080
2081
2082
2083
2084
2085
2086
2087
2088
2089
2090
2091
2092
2093
2094
2095
2096
2097
2098
2099
2100
2101
2102
2103
2104
2105
2106
2107
2108
2109
2110
2111
2112
2113
2114
2115
2116
2117
2118
2119
2120
2121
2122
2123
2124
2125
2126
2127
2128
2129
2130
2131
2132
2133
2134
2135
2136
2137
2138
2139
2140
2141
2142
2143
2144
2145
2146
2147
2148
2149
2150
2151
2152
2153
2154
2155
2156
2157
2158
2159
2160
2161
2162
2163
2164
2165
2166
2167
2168
2169
2170
2171
2172
2173
2174
2175
2176
2177
2178
2179
2180
2181
2182
2183
2184
2185
2186
2187
2188
2189
2190
2191
2192
2193
2194
2195
2196
2197
2198
2199
2200
2201
2202
2203
2204
2205
2206
2207
2208
2209
2210
2211
2212
2213
2214
2215
2216
2217
2218
2219
2220
2221
2222
2223
2224
2225
2226
2227
2228
2229
2230
2231
2232
2233
2234
2235
2236
2237
2238
2239
2240
2241
2242
2243
2244
2245
2246
2247
2248
2249
2250
2251
2252
2253
2254
2255
2256
2257
2258
2259
2260
2261
2262
2263
2264
2265
2266
2267
2268
2269
2270
2271
2272
2273
2274
2275
2276
2277
2278
2279
2280
2281
2282
2283
2284
2285
2286
2287
2288
2289
2290
2291
2292
2293
2294
2295
2296
2297
2298
2299
2300
2301
2302
2303
2304
2305
2306
2307
2308
2309
2310
2311
2312
2313
2314
2315
2316
2317
2318
2319
2320
2321
2322
2323
2324
2325
2326
2327
2328
2329
2330
2331
2332
2333
2334
2335
2336
2337
2338
2339
2340
2341
2342
2343
2344
2345
2346
2347
2348
2349
2350
2351
2352
2353
2354
2355
2356
2357
2358
2359
2360
2361
2362
2363
2364
2365
2366
2367
2368
2369
2370
2371
2372
2373
2374
2375
2376
2377
2378
2379
2380
2381
2382
2383
2384
2385
2386
2387
2388
2389
2390
2391
2392
2393
2394
2395
2396
2397
2398
2399
2400
2401
2402
2403
2404
2405
2406
2407
2408
2409
2410
2411
2412
2413
2414
2415
2416
2417
2418
2419
2420
2421
2422
2423
2424
2425
2426
2427
2428
2429
2430
2431
2432
2433
2434
2435
2436
2437
2438
2439
2440
2441
2442
2443
2444
2445
2446
2447
2448
2449
2450
2451
2452
2453
2454
2455
2456
2457
2458
2459
2460
2461
2462
2463
2464
2465
2466
2467
2468
2469
2470
2471
2472
2473
2474
2475
2476
2477
2478
2479
2480
2481
2482
2483
2484
2485
2486
2487
2488
2489
2490
2491
2492
2493
2494
2495
2496
2497
2498
2499
2500
2501
2502
2503
2504
2505
2506
2507
2508
2509
2510
2511
2512
2513
2514
2515
2516
2517
2518
2519
2520
2521
2522
2523
2524
2525
2526
2527
2528
2529
2530
2531
2532
2533
2534
2535
2536
2537
2538
2539
2540
2541
2542
2543
2544
2545
2546
2547
2548
2549
2550
2551
2552
2553
2554
2555
2556
2557
2558
2559
2560
2561
2562
2563
2564
2565
2566
2567
2568
2569
2570
2571
2572
2573
2574
2575
2576
2577
2578
2579
2580
2581
2582
2583
2584
2585
2586
2587
2588
2589
2590
2591
2592
2593
2594
2595
2596
2597
2598
2599
2600
2601
2602
2603
2604
2605
2606
2607
2608
2609
2610
2611
2612
2613
2614
2615
2616
2617
2618
2619
2620
2621
2622
2623
2624
2625
2626
2627
2628
2629
2630
2631
2632
2633
2634
2635
2636
2637
2638
2639
2640
2641
2642
2643
2644
2645
2646
2647
2648
2649
2650
2651
2652
2653
2654
2655
2656
2657
2658
2659
2660
2661
2662
2663
2664
2665
2666
2667
2668
2669
2670
2671
2672
2673
2674
2675
2676
2677
2678
2679
2680
2681
2682
2683
2684
2685
2686
2687
2688
2689
2690
2691
2692
2693
2694
2695
2696
2697
2698
2699
2700
2701
2702
2703
2704
2705
2706
2707
2708
2709
2710
2711
2712
2713
2714
2715
2716
2717
2718
2719
2720
2721
2722
2723
2724
2725
2726
2727
2728
2729
2730
2731
2732
2733
2734
2735
2736
2737
2738
2739
2740
2741
2742
2743
2744
2745
2746
2747
2748
2749
2750
2751
2752
2753
2754
2755
2756
2757
2758
2759
2760
2761
2762
2763
2764
2765
2766
2767
2768
2769
2770
2771
2772
2773
2774
2775
2776
2777
2778
2779
2780
2781
2782
2783
2784
2785
2786
2787
2788
2789
2790
2791
2792
2793
2794
2795
2796
2797
2798
2799
2800
2801
2802
2803
2804
2805
2806
2807
2808
2809
2810
2811
2812
2813
2814
2815
2816
2817
2818
2819
2820
2821
2822
2823
2824
2825
2826
2827
2828
2829
2830
2831
2832
2833
2834
2835
2836
2837
2838
2839
2840
2841
2842
2843
2844
2845
2846
2847
2848
2849
2850
2851
2852
2853
2854
2855
2856
2857
2858
2859
2860
2861
2862
2863
2864
2865
2866
2867
2868
2869
2870
2871
2872
2873
2874
2875
2876
2877
2878
2879
2880
2881
2882
2883
2884
2885
2886
2887
2888
2889
2890
2891
2892
2893
2894
2895
2896
2897
2898
2899
2900
2901
2902
2903
2904
2905
2906
2907
2908
2909
2910
2911
2912
2913
2914
2915
2916
2917
2918
2919
2920
2921
2922
2923
2924
2925
2926
2927
2928
2929
2930
2931
2932
2933
2934
2935
2936
2937
2938
2939
2940
2941
2942
2943
2944
2945
2946
2947
2948
2949
2950
2951
2952
2953
2954
2955
2956
2957
2958
2959
2960
2961
2962
2963
2964
2965
2966
2967
2968
2969
2970
2971
2972
2973
2974
2975
2976
2977
2978
2979
2980
2981
2982
2983
2984
2985
2986
2987
2988
2989
2990
2991
2992
2993
2994
2995
2996
2997
2998
2999
3000
3001
3002
3003
3004
3005
3006
3007
3008
3009
3010
3011
3012
3013
3014
3015
3016
3017
3018
3019
3020
3021
3022
3023
3024
3025
3026
3027
3028
3029
3030
3031
3032
3033
3034
3035
3036
3037
3038
3039
3040
3041
3042
3043
3044
3045
3046
3047
3048
3049
3050
3051
3052
3053
3054
3055
3056
3057
3058
3059
3060
3061
3062
3063
3064
3065
3066
3067
3068
3069
3070
3071
3072
3073
3074
3075
3076
3077
3078
3079
3080
3081
3082
3083
3084
3085
3086
3087
3088
3089
3090
3091
3092
3093
3094
3095
3096
3097
3098
3099
3100
3101
3102
3103
3104
3105
3106
3107
3108
3109
3110
3111
3112
3113
3114
3115
3116
3117
3118
3119
3120
3121
3122
3123
3124
3125
3126
3127
3128
3129
3130
3131
3132
3133
3134
3135
3136
3137
3138
3139
3140
3141
3142
3143
3144
3145
3146
3147
3148
3149
3150
3151
3152
3153
3154
3155
3156
3157
3158
3159
3160
3161
3162
3163
3164
3165
3166
3167
3168
3169
3170
3171
3172
3173
3174
3175
3176
3177
3178
3179
3180
3181
3182
3183
3184
3185
3186
3187
3188
3189
3190
3191
3192
3193
3194
3195
3196
3197
3198
3199
3200
3201
3202
3203
3204
3205
3206
3207
3208
3209
3210
3211
3212
3213
3214
3215
3216
3217
3218
3219
3220
3221
3222
3223
3224
3225
3226
3227
3228
3229
3230
3231
3232
3233
3234
3235
3236
3237
3238
3239
3240
3241
3242
3243
3244
3245
3246
3247
3248
3249
3250
3251
3252
3253
3254
3255
3256
3257
3258
3259
3260
3261
3262
3263
3264
3265
3266
3267
3268
3269
3270
3271
3272
3273
3274
3275
3276
3277
3278
3279
3280
3281
3282
3283
3284
3285
3286
3287
3288
3289
3290
3291
3292
3293
3294
3295
3296
3297
3298
3299
3300
3301
3302
3303
3304
3305
3306
3307
3308
3309
3310
3311
3312
3313
3314
3315
3316
3317
3318
3319
3320
3321
3322
3323
3324
3325
3326
3327
3328
3329
3330
3331
3332
3333
3334
3335
3336
3337
3338
3339
3340
3341
3342
3343
3344
3345
3346
3347
3348
3349
3350
3351
3352
3353
3354
3355
3356
3357
3358
3359
3360
3361
3362
3363
3364
3365
3366
3367
3368
3369
3370
3371
3372
3373
3374
3375
3376
3377
3378
3379
3380
3381
3382
3383
3384
3385
3386
3387
3388
3389
3390
3391
3392
3393
3394
3395
3396
3397
3398
3399
3400
3401
3402
3403
3404
3405
3406
3407
3408
3409
3410
3411
3412
3413
3414
3415
3416
3417
3418
3419
3420
3421
3422
3423
3424
3425
3426
3427
3428
3429
3430
3431
3432
3433
3434
3435
3436
3437
3438
3439
3440
3441
3442
3443
3444
3445
3446
3447
3448
3449
3450
3451
3452
3453
3454
3455
3456
3457
3458
3459
3460
3461
3462
3463
3464
3465
3466
3467
3468
3469
3470
3471
3472
3473
3474
3475
3476
3477
3478
3479
3480
3481
3482
3483
3484
3485
3486
3487
3488
3489
3490
3491
3492
3493
3494
3495
3496
3497
3498
3499
3500
3501
3502
3503
3504
3505
3506
3507
3508
3509
3510
3511
3512
3513
3514
3515
3516
3517
3518
3519
3520
3521
3522
3523
3524
3525
3526
3527
3528
3529
3530
3531
3532
3533
3534
3535
3536
3537
3538
3539
3540
3541
3542
3543
3544
3545
3546
3547
3548
3549
3550
3551
3552
3553
3554
3555
3556
3557
3558
3559
3560
3561
3562
3563
3564
3565
3566
3567
3568
3569
3570
3571
3572
3573
3574
3575
3576
3577
3578
3579
3580
3581
3582
3583
3584
3585
3586
3587
3588
3589
3590
3591
3592
3593
3594
3595
3596
3597
3598
3599
3600
3601
3602
3603
3604
3605
3606
3607
3608
3609
3610
3611
3612
3613
3614
3615
3616
3617
3618
3619
3620
3621
3622
3623
3624
3625
3626
3627
3628
3629
3630
3631
3632
3633
3634
3635
3636
3637
3638
3639
3640
3641
3642
3643
3644
3645
3646
3647
3648
3649
3650
3651
3652
3653
3654
3655
3656
3657
3658
3659
3660
3661
3662
3663
3664
3665
3666
3667
3668
3669
3670
3671
3672
3673
3674
3675
3676
3677
3678
3679
3680
3681
3682
3683
3684
3685
3686
3687
3688
3689
3690
3691
3692
3693
3694
3695
3696
3697
3698
3699
3700
3701
3702
3703
3704
3705
3706
3707
3708
3709
3710
3711
3712
3713
3714
3715
3716
3717
3718
3719
3720
3721
3722
3723
3724
3725
3726
3727
3728
3729
3730
3731
3732
3733
3734
3735
3736
3737
3738
3739
3740
3741
3742
3743
3744
3745
3746
3747
3748
3749
3750
3751
3752
3753
3754
3755
3756
3757
3758
3759
3760
3761
3762
3763
3764
3765
3766
3767
3768
3769
3770
3771
3772
3773
3774
3775
3776
3777
3778
3779
3780
3781
3782
3783
3784
3785
3786
3787
3788
3789
3790
3791
3792
3793
3794
3795
3796
3797
3798
3799
3800
3801
3802
3803
3804
3805
3806
3807
3808
3809
3810
3811
3812
3813
3814
3815
3816
3817
3818
3819
3820
3821
3822
3823
3824
3825
3826
3827
3828
3829
3830
3831
3832
3833
3834
3835
3836
3837
3838
3839
3840
3841
3842
3843
3844
3845
3846
3847
3848
3849
3850
3851
3852
3853
3854
3855
3856
3857
3858
3859
3860
3861
3862
3863
3864
3865
3866
3867
3868
3869
3870
3871
3872
3873
3874
3875
3876
3877
3878
3879
3880
3881
3882
3883
3884
3885
3886
3887
3888
3889
3890
3891
3892
3893
3894
3895
3896
3897
3898
3899
3900
3901
3902
3903
3904
3905
3906
3907
3908
3909
3910
3911
3912
3913
3914
3915
3916
3917
3918
3919
3920
3921
3922
3923
3924
3925
3926
3927
3928
3929
3930
3931
3932
3933
3934
3935
3936
3937
3938
3939
3940
3941
3942
3943
3944
3945
3946
3947
3948
3949
3950
3951
3952
3953
3954
3955
3956
3957
3958
3959
3960
3961
3962
3963
3964
3965
3966
3967
3968
3969
3970
3971
3972
3973
3974
3975
3976
3977
3978
3979
3980
3981
3982
3983
3984
3985
3986
3987
3988
3989
3990
3991
3992
3993
3994
3995
3996
3997
3998
3999
4000
4001
4002
4003
4004
4005
4006
4007
4008
4009
4010
4011
4012
4013
4014
4015
4016
4017
4018
4019
4020
4021
4022
4023
4024
4025
4026
4027
4028
4029
4030
4031
4032
4033
4034
4035
4036
4037
4038
4039
4040
4041
4042
4043
4044
4045
4046
4047
4048
4049
4050
4051
4052
4053
4054
4055
4056
4057
4058
4059
4060
4061
4062
4063
4064
4065
4066
4067
4068
4069
4070
4071
4072
4073
4074
4075
4076
4077
4078
4079
4080
4081
4082
4083
4084
4085
4086
4087
4088
4089
4090
4091
4092
4093
4094
4095
4096
4097
4098
4099
4100
4101
4102
4103
4104
4105
4106
4107
4108
4109
4110
4111
4112
4113
4114
4115
4116
4117
4118
4119
4120
4121
4122
4123
4124
4125
4126
4127
4128
4129
4130
4131
4132
4133
4134
4135
4136
4137
4138
4139
4140
4141
4142
4143
4144
4145
4146
4147
4148
4149
4150
4151
4152
4153
4154
4155
4156
4157
4158
4159
4160
4161
4162
4163
4164
4165
4166
4167
4168
4169
4170
4171
4172
4173
4174
4175
4176
4177
4178
4179
4180
4181
4182
4183
4184
4185
4186
4187
4188
4189
4190
4191
4192
4193
4194
4195
4196
4197
4198
4199
4200
4201
4202
// SPDX-License-Identifier: GPL-2.0
/*
 * Shared application/kernel submission and completion ring pairs, for
 * supporting fast/efficient IO.
 *
 * A note on the read/write ordering memory barriers that are matched between
 * the application and kernel side.
 *
 * After the application reads the CQ ring tail, it must use an
 * appropriate smp_rmb() to pair with the smp_wmb() the kernel uses
 * before writing the tail (using smp_load_acquire to read the tail will
 * do). It also needs a smp_mb() before updating CQ head (ordering the
 * entry load(s) with the head store), pairing with an implicit barrier
 * through a control-dependency in io_get_cqe (smp_store_release to
 * store head will do). Failure to do so could lead to reading invalid
 * CQ entries.
 *
 * Likewise, the application must use an appropriate smp_wmb() before
 * writing the SQ tail (ordering SQ entry stores with the tail store),
 * which pairs with smp_load_acquire in io_get_sqring (smp_store_release
 * to store the tail will do). And it needs a barrier ordering the SQ
 * head load before writing new SQ entries (smp_load_acquire to read
 * head will do).
 *
 * When using the SQ poll thread (IORING_SETUP_SQPOLL), the application
 * needs to check the SQ flags for IORING_SQ_NEED_WAKEUP *after*
 * updating the SQ tail; a full memory barrier smp_mb() is needed
 * between.
 *
 * Also see the examples in the liburing library:
 *
 *	git://git.kernel.dk/liburing
 *
 * io_uring also uses READ/WRITE_ONCE() for _any_ store or load that happens
 * from data shared between the kernel and application. This is done both
 * for ordering purposes, but also to ensure that once a value is loaded from
 * data that the application could potentially modify, it remains stable.
 *
 * Copyright (C) 2018-2019 Jens Axboe
 * Copyright (c) 2018-2019 Christoph Hellwig
 */
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/errno.h>
#include <linux/syscalls.h>
#include <net/compat.h>
#include <linux/refcount.h>
#include <linux/uio.h>
#include <linux/bits.h>

#include <linux/sched/signal.h>
#include <linux/fs.h>
#include <linux/file.h>
#include <linux/fdtable.h>
#include <linux/mm.h>
#include <linux/mman.h>
#include <linux/percpu.h>
#include <linux/slab.h>
#include <linux/bvec.h>
#include <linux/net.h>
#include <net/sock.h>
#include <linux/anon_inodes.h>
#include <linux/sched/mm.h>
#include <linux/uaccess.h>
#include <linux/nospec.h>
#include <linux/highmem.h>
#include <linux/fsnotify.h>
#include <linux/fadvise.h>
#include <linux/task_work.h>
#include <linux/io_uring.h>
#include <linux/io_uring/cmd.h>
#include <linux/audit.h>
#include <linux/security.h>
#include <asm/shmparam.h>

#define CREATE_TRACE_POINTS
#include <trace/events/io_uring.h>

#include <uapi/linux/io_uring.h>

#include "io-wq.h"

#include "io_uring.h"
#include "opdef.h"
#include "refs.h"
#include "tctx.h"
#include "register.h"
#include "sqpoll.h"
#include "fdinfo.h"
#include "kbuf.h"
#include "rsrc.h"
#include "cancel.h"
#include "net.h"
#include "notif.h"
#include "waitid.h"
#include "futex.h"
#include "napi.h"

#include "timeout.h"
#include "poll.h"
#include "rw.h"
#include "alloc_cache.h"

#define IORING_MAX_ENTRIES	32768
#define IORING_MAX_CQ_ENTRIES	(2 * IORING_MAX_ENTRIES)

#define SQE_COMMON_FLAGS (IOSQE_FIXED_FILE | IOSQE_IO_LINK | \
			  IOSQE_IO_HARDLINK | IOSQE_ASYNC)

#define SQE_VALID_FLAGS	(SQE_COMMON_FLAGS | IOSQE_BUFFER_SELECT | \
			IOSQE_IO_DRAIN | IOSQE_CQE_SKIP_SUCCESS)

#define IO_REQ_CLEAN_FLAGS (REQ_F_BUFFER_SELECTED | REQ_F_NEED_CLEANUP | \
				REQ_F_POLLED | REQ_F_INFLIGHT | REQ_F_CREDS | \
				REQ_F_ASYNC_DATA)

#define IO_REQ_CLEAN_SLOW_FLAGS (REQ_F_REFCOUNT | REQ_F_LINK | REQ_F_HARDLINK |\
				 IO_REQ_CLEAN_FLAGS)

#define IO_TCTX_REFS_CACHE_NR	(1U << 10)

#define IO_COMPL_BATCH			32
#define IO_REQ_ALLOC_BATCH		8

struct io_defer_entry {
	struct list_head	list;
	struct io_kiocb		*req;
	u32			seq;
};

/* requests with any of those set should undergo io_disarm_next() */
#define IO_DISARM_MASK (REQ_F_ARM_LTIMEOUT | REQ_F_LINK_TIMEOUT | REQ_F_FAIL)
#define IO_REQ_LINK_FLAGS (REQ_F_LINK | REQ_F_HARDLINK)

/*
 * No waiters. It's larger than any valid value of the tw counter
 * so that tests against ->cq_wait_nr would fail and skip wake_up().
 */
#define IO_CQ_WAKE_INIT		(-1U)
/* Forced wake up if there is a waiter regardless of ->cq_wait_nr */
#define IO_CQ_WAKE_FORCE	(IO_CQ_WAKE_INIT >> 1)

static bool io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
					 struct task_struct *task,
					 bool cancel_all);

static void io_queue_sqe(struct io_kiocb *req);

struct kmem_cache *req_cachep;
static struct workqueue_struct *iou_wq __ro_after_init;

static int __read_mostly sysctl_io_uring_disabled;
static int __read_mostly sysctl_io_uring_group = -1;

#ifdef CONFIG_SYSCTL
static struct ctl_table kernel_io_uring_disabled_table[] = {
	{
		.procname	= "io_uring_disabled",
		.data		= &sysctl_io_uring_disabled,
		.maxlen		= sizeof(sysctl_io_uring_disabled),
		.mode		= 0644,
		.proc_handler	= proc_dointvec_minmax,
		.extra1		= SYSCTL_ZERO,
		.extra2		= SYSCTL_TWO,
	},
	{
		.procname	= "io_uring_group",
		.data		= &sysctl_io_uring_group,
		.maxlen		= sizeof(gid_t),
		.mode		= 0644,
		.proc_handler	= proc_dointvec,
	},
	{},
};
#endif

static inline void io_submit_flush_completions(struct io_ring_ctx *ctx)
{
	if (!wq_list_empty(&ctx->submit_state.compl_reqs) ||
	    ctx->submit_state.cqes_count)
		__io_submit_flush_completions(ctx);
}

static inline unsigned int __io_cqring_events(struct io_ring_ctx *ctx)
{
	return ctx->cached_cq_tail - READ_ONCE(ctx->rings->cq.head);
}

static inline unsigned int __io_cqring_events_user(struct io_ring_ctx *ctx)
{
	return READ_ONCE(ctx->rings->cq.tail) - READ_ONCE(ctx->rings->cq.head);
}

static bool io_match_linked(struct io_kiocb *head)
{
	struct io_kiocb *req;

	io_for_each_link(req, head) {
		if (req->flags & REQ_F_INFLIGHT)
			return true;
	}
	return false;
}

/*
 * As io_match_task() but protected against racing with linked timeouts.
 * User must not hold timeout_lock.
 */
bool io_match_task_safe(struct io_kiocb *head, struct task_struct *task,
			bool cancel_all)
{
	bool matched;

	if (task && head->task != task)
		return false;
	if (cancel_all)
		return true;

	if (head->flags & REQ_F_LINK_TIMEOUT) {
		struct io_ring_ctx *ctx = head->ctx;

		/* protect against races with linked timeouts */
		spin_lock_irq(&ctx->timeout_lock);
		matched = io_match_linked(head);
		spin_unlock_irq(&ctx->timeout_lock);
	} else {
		matched = io_match_linked(head);
	}
	return matched;
}

static inline void req_fail_link_node(struct io_kiocb *req, int res)
{
	req_set_fail(req);
	io_req_set_res(req, res, 0);
}

static inline void io_req_add_to_cache(struct io_kiocb *req, struct io_ring_ctx *ctx)
{
	wq_stack_add_head(&req->comp_list, &ctx->submit_state.free_list);
}

static __cold void io_ring_ctx_ref_free(struct percpu_ref *ref)
{
	struct io_ring_ctx *ctx = container_of(ref, struct io_ring_ctx, refs);

	complete(&ctx->ref_comp);
}

static __cold void io_fallback_req_func(struct work_struct *work)
{
	struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx,
						fallback_work.work);
	struct llist_node *node = llist_del_all(&ctx->fallback_llist);
	struct io_kiocb *req, *tmp;
	struct io_tw_state ts = { .locked = true, };

	percpu_ref_get(&ctx->refs);
	mutex_lock(&ctx->uring_lock);
	llist_for_each_entry_safe(req, tmp, node, io_task_work.node)
		req->io_task_work.func(req, &ts);
	if (WARN_ON_ONCE(!ts.locked))
		return;
	io_submit_flush_completions(ctx);
	mutex_unlock(&ctx->uring_lock);
	percpu_ref_put(&ctx->refs);
}

static int io_alloc_hash_table(struct io_hash_table *table, unsigned bits)
{
	unsigned hash_buckets = 1U << bits;
	size_t hash_size = hash_buckets * sizeof(table->hbs[0]);

	table->hbs = kmalloc(hash_size, GFP_KERNEL);
	if (!table->hbs)
		return -ENOMEM;

	table->hash_bits = bits;
	init_hash_table(table, hash_buckets);
	return 0;
}

static __cold struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
{
	struct io_ring_ctx *ctx;
	int hash_bits;

	ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
	if (!ctx)
		return NULL;

	xa_init(&ctx->io_bl_xa);

	/*
	 * Use 5 bits less than the max cq entries, that should give us around
	 * 32 entries per hash list if totally full and uniformly spread, but
	 * don't keep too many buckets to not overconsume memory.
	 */
	hash_bits = ilog2(p->cq_entries) - 5;
	hash_bits = clamp(hash_bits, 1, 8);
	if (io_alloc_hash_table(&ctx->cancel_table, hash_bits))
		goto err;
	if (io_alloc_hash_table(&ctx->cancel_table_locked, hash_bits))
		goto err;
	if (percpu_ref_init(&ctx->refs, io_ring_ctx_ref_free,
			    0, GFP_KERNEL))
		goto err;

	ctx->flags = p->flags;
	atomic_set(&ctx->cq_wait_nr, IO_CQ_WAKE_INIT);
	init_waitqueue_head(&ctx->sqo_sq_wait);
	INIT_LIST_HEAD(&ctx->sqd_list);
	INIT_LIST_HEAD(&ctx->cq_overflow_list);
	INIT_LIST_HEAD(&ctx->io_buffers_cache);
	INIT_HLIST_HEAD(&ctx->io_buf_list);
	io_alloc_cache_init(&ctx->rsrc_node_cache, IO_NODE_ALLOC_CACHE_MAX,
			    sizeof(struct io_rsrc_node));
	io_alloc_cache_init(&ctx->apoll_cache, IO_ALLOC_CACHE_MAX,
			    sizeof(struct async_poll));
	io_alloc_cache_init(&ctx->netmsg_cache, IO_ALLOC_CACHE_MAX,
			    sizeof(struct io_async_msghdr));
	io_futex_cache_init(ctx);
	init_completion(&ctx->ref_comp);
	xa_init_flags(&ctx->personalities, XA_FLAGS_ALLOC1);
	mutex_init(&ctx->uring_lock);
	init_waitqueue_head(&ctx->cq_wait);
	init_waitqueue_head(&ctx->poll_wq);
	init_waitqueue_head(&ctx->rsrc_quiesce_wq);
	spin_lock_init(&ctx->completion_lock);
	spin_lock_init(&ctx->timeout_lock);
	INIT_WQ_LIST(&ctx->iopoll_list);
	INIT_LIST_HEAD(&ctx->io_buffers_comp);
	INIT_LIST_HEAD(&ctx->defer_list);
	INIT_LIST_HEAD(&ctx->timeout_list);
	INIT_LIST_HEAD(&ctx->ltimeout_list);
	INIT_LIST_HEAD(&ctx->rsrc_ref_list);
	init_llist_head(&ctx->work_llist);
	INIT_LIST_HEAD(&ctx->tctx_list);
	ctx->submit_state.free_list.next = NULL;
	INIT_WQ_LIST(&ctx->locked_free_list);
	INIT_HLIST_HEAD(&ctx->waitid_list);
#ifdef CONFIG_FUTEX
	INIT_HLIST_HEAD(&ctx->futex_list);
#endif
	INIT_DELAYED_WORK(&ctx->fallback_work, io_fallback_req_func);
	INIT_WQ_LIST(&ctx->submit_state.compl_reqs);
	INIT_HLIST_HEAD(&ctx->cancelable_uring_cmd);
	io_napi_init(ctx);

	return ctx;
err:
	kfree(ctx->cancel_table.hbs);
	kfree(ctx->cancel_table_locked.hbs);
	xa_destroy(&ctx->io_bl_xa);
	kfree(ctx);
	return NULL;
}

static void io_account_cq_overflow(struct io_ring_ctx *ctx)
{
	struct io_rings *r = ctx->rings;

	WRITE_ONCE(r->cq_overflow, READ_ONCE(r->cq_overflow) + 1);
	ctx->cq_extra--;
}

static bool req_need_defer(struct io_kiocb *req, u32 seq)
{
	if (unlikely(req->flags & REQ_F_IO_DRAIN)) {
		struct io_ring_ctx *ctx = req->ctx;

		return seq + READ_ONCE(ctx->cq_extra) != ctx->cached_cq_tail;
	}

	return false;
}

static void io_clean_op(struct io_kiocb *req)
{
	if (req->flags & REQ_F_BUFFER_SELECTED) {
		spin_lock(&req->ctx->completion_lock);
		io_put_kbuf_comp(req);
		spin_unlock(&req->ctx->completion_lock);
	}

	if (req->flags & REQ_F_NEED_CLEANUP) {
		const struct io_cold_def *def = &io_cold_defs[req->opcode];

		if (def->cleanup)
			def->cleanup(req);
	}
	if ((req->flags & REQ_F_POLLED) && req->apoll) {
		kfree(req->apoll->double_poll);
		kfree(req->apoll);
		req->apoll = NULL;
	}
	if (req->flags & REQ_F_INFLIGHT) {
		struct io_uring_task *tctx = req->task->io_uring;

		atomic_dec(&tctx->inflight_tracked);
	}
	if (req->flags & REQ_F_CREDS)
		put_cred(req->creds);
	if (req->flags & REQ_F_ASYNC_DATA) {
		kfree(req->async_data);
		req->async_data = NULL;
	}
	req->flags &= ~IO_REQ_CLEAN_FLAGS;
}

static inline void io_req_track_inflight(struct io_kiocb *req)
{
	if (!(req->flags & REQ_F_INFLIGHT)) {
		req->flags |= REQ_F_INFLIGHT;
		atomic_inc(&req->task->io_uring->inflight_tracked);
	}
}

static struct io_kiocb *__io_prep_linked_timeout(struct io_kiocb *req)
{
	if (WARN_ON_ONCE(!req->link))
		return NULL;

	req->flags &= ~REQ_F_ARM_LTIMEOUT;
	req->flags |= REQ_F_LINK_TIMEOUT;

	/* linked timeouts should have two refs once prep'ed */
	io_req_set_refcount(req);
	__io_req_set_refcount(req->link, 2);
	return req->link;
}

static inline struct io_kiocb *io_prep_linked_timeout(struct io_kiocb *req)
{
	if (likely(!(req->flags & REQ_F_ARM_LTIMEOUT)))
		return NULL;
	return __io_prep_linked_timeout(req);
}

static noinline void __io_arm_ltimeout(struct io_kiocb *req)
{
	io_queue_linked_timeout(__io_prep_linked_timeout(req));
}

static inline void io_arm_ltimeout(struct io_kiocb *req)
{
	if (unlikely(req->flags & REQ_F_ARM_LTIMEOUT))
		__io_arm_ltimeout(req);
}

static void io_prep_async_work(struct io_kiocb *req)
{
	const struct io_issue_def *def = &io_issue_defs[req->opcode];
	struct io_ring_ctx *ctx = req->ctx;

	if (!(req->flags & REQ_F_CREDS)) {
		req->flags |= REQ_F_CREDS;
		req->creds = get_current_cred();
	}

	req->work.list.next = NULL;
	req->work.flags = 0;
	if (req->flags & REQ_F_FORCE_ASYNC)
		req->work.flags |= IO_WQ_WORK_CONCURRENT;

	if (req->file && !(req->flags & REQ_F_FIXED_FILE))
		req->flags |= io_file_get_flags(req->file);

	if (req->file && (req->flags & REQ_F_ISREG)) {
		bool should_hash = def->hash_reg_file;

		/* don't serialize this request if the fs doesn't need it */
		if (should_hash && (req->file->f_flags & O_DIRECT) &&
		    (req->file->f_mode & FMODE_DIO_PARALLEL_WRITE))
			should_hash = false;
		if (should_hash || (ctx->flags & IORING_SETUP_IOPOLL))
			io_wq_hash_work(&req->work, file_inode(req->file));
	} else if (!req->file || !S_ISBLK(file_inode(req->file)->i_mode)) {
		if (def->unbound_nonreg_file)
			req->work.flags |= IO_WQ_WORK_UNBOUND;
	}
}

static void io_prep_async_link(struct io_kiocb *req)
{
	struct io_kiocb *cur;

	if (req->flags & REQ_F_LINK_TIMEOUT) {
		struct io_ring_ctx *ctx = req->ctx;

		spin_lock_irq(&ctx->timeout_lock);
		io_for_each_link(cur, req)
			io_prep_async_work(cur);
		spin_unlock_irq(&ctx->timeout_lock);
	} else {
		io_for_each_link(cur, req)
			io_prep_async_work(cur);
	}
}

void io_queue_iowq(struct io_kiocb *req, struct io_tw_state *ts_dont_use)
{
	struct io_kiocb *link = io_prep_linked_timeout(req);
	struct io_uring_task *tctx = req->task->io_uring;

	BUG_ON(!tctx);
	BUG_ON(!tctx->io_wq);

	/* init ->work of the whole link before punting */
	io_prep_async_link(req);

	/*
	 * Not expected to happen, but if we do have a bug where this _can_
	 * happen, catch it here and ensure the request is marked as
	 * canceled. That will make io-wq go through the usual work cancel
	 * procedure rather than attempt to run this request (or create a new
	 * worker for it).
	 */
	if (WARN_ON_ONCE(!same_thread_group(req->task, current)))
		req->work.flags |= IO_WQ_WORK_CANCEL;

	trace_io_uring_queue_async_work(req, io_wq_is_hashed(&req->work));
	io_wq_enqueue(tctx->io_wq, &req->work);
	if (link)
		io_queue_linked_timeout(link);
}

static __cold void io_queue_deferred(struct io_ring_ctx *ctx)
{
	while (!list_empty(&ctx->defer_list)) {
		struct io_defer_entry *de = list_first_entry(&ctx->defer_list,
						struct io_defer_entry, list);

		if (req_need_defer(de->req, de->seq))
			break;
		list_del_init(&de->list);
		io_req_task_queue(de->req);
		kfree(de);
	}
}

void io_eventfd_ops(struct rcu_head *rcu)
{
	struct io_ev_fd *ev_fd = container_of(rcu, struct io_ev_fd, rcu);
	int ops = atomic_xchg(&ev_fd->ops, 0);

	if (ops & BIT(IO_EVENTFD_OP_SIGNAL_BIT))
		eventfd_signal_mask(ev_fd->cq_ev_fd, EPOLL_URING_WAKE);

	/* IO_EVENTFD_OP_FREE_BIT may not be set here depending on callback
	 * ordering in a race but if references are 0 we know we have to free
	 * it regardless.
	 */
	if (atomic_dec_and_test(&ev_fd->refs)) {
		eventfd_ctx_put(ev_fd->cq_ev_fd);
		kfree(ev_fd);
	}
}

static void io_eventfd_signal(struct io_ring_ctx *ctx)
{
	struct io_ev_fd *ev_fd = NULL;

	rcu_read_lock();
	/*
	 * rcu_dereference ctx->io_ev_fd once and use it for both for checking
	 * and eventfd_signal
	 */
	ev_fd = rcu_dereference(ctx->io_ev_fd);

	/*
	 * Check again if ev_fd exists incase an io_eventfd_unregister call
	 * completed between the NULL check of ctx->io_ev_fd at the start of
	 * the function and rcu_read_lock.
	 */
	if (unlikely(!ev_fd))
		goto out;
	if (READ_ONCE(ctx->rings->cq_flags) & IORING_CQ_EVENTFD_DISABLED)
		goto out;
	if (ev_fd->eventfd_async && !io_wq_current_is_worker())
		goto out;

	if (likely(eventfd_signal_allowed())) {
		eventfd_signal_mask(ev_fd->cq_ev_fd, EPOLL_URING_WAKE);
	} else {
		atomic_inc(&ev_fd->refs);
		if (!atomic_fetch_or(BIT(IO_EVENTFD_OP_SIGNAL_BIT), &ev_fd->ops))
			call_rcu_hurry(&ev_fd->rcu, io_eventfd_ops);
		else
			atomic_dec(&ev_fd->refs);
	}

out:
	rcu_read_unlock();
}

static void io_eventfd_flush_signal(struct io_ring_ctx *ctx)
{
	bool skip;

	spin_lock(&ctx->completion_lock);

	/*
	 * Eventfd should only get triggered when at least one event has been
	 * posted. Some applications rely on the eventfd notification count
	 * only changing IFF a new CQE has been added to the CQ ring. There's
	 * no depedency on 1:1 relationship between how many times this
	 * function is called (and hence the eventfd count) and number of CQEs
	 * posted to the CQ ring.
	 */
	skip = ctx->cached_cq_tail == ctx->evfd_last_cq_tail;
	ctx->evfd_last_cq_tail = ctx->cached_cq_tail;
	spin_unlock(&ctx->completion_lock);
	if (skip)
		return;

	io_eventfd_signal(ctx);
}

void __io_commit_cqring_flush(struct io_ring_ctx *ctx)
{
	if (ctx->poll_activated)
		io_poll_wq_wake(ctx);
	if (ctx->off_timeout_used)
		io_flush_timeouts(ctx);
	if (ctx->drain_active) {
		spin_lock(&ctx->completion_lock);
		io_queue_deferred(ctx);
		spin_unlock(&ctx->completion_lock);
	}
	if (ctx->has_evfd)
		io_eventfd_flush_signal(ctx);
}

static inline void __io_cq_lock(struct io_ring_ctx *ctx)
{
	if (!ctx->lockless_cq)
		spin_lock(&ctx->completion_lock);
}

static inline void io_cq_lock(struct io_ring_ctx *ctx)
	__acquires(ctx->completion_lock)
{
	spin_lock(&ctx->completion_lock);
}

static inline void __io_cq_unlock_post(struct io_ring_ctx *ctx)
{
	io_commit_cqring(ctx);
	if (!ctx->task_complete) {
		if (!ctx->lockless_cq)
			spin_unlock(&ctx->completion_lock);
		/* IOPOLL rings only need to wake up if it's also SQPOLL */
		if (!ctx->syscall_iopoll)
			io_cqring_wake(ctx);
	}
	io_commit_cqring_flush(ctx);
}

static void io_cq_unlock_post(struct io_ring_ctx *ctx)
	__releases(ctx->completion_lock)
{
	io_commit_cqring(ctx);
	spin_unlock(&ctx->completion_lock);
	io_cqring_wake(ctx);
	io_commit_cqring_flush(ctx);
}

static void io_cqring_overflow_kill(struct io_ring_ctx *ctx)
{
	struct io_overflow_cqe *ocqe;
	LIST_HEAD(list);

	spin_lock(&ctx->completion_lock);
	list_splice_init(&ctx->cq_overflow_list, &list);
	clear_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq);
	spin_unlock(&ctx->completion_lock);

	while (!list_empty(&list)) {
		ocqe = list_first_entry(&list, struct io_overflow_cqe, list);
		list_del(&ocqe->list);
		kfree(ocqe);
	}
}

static void __io_cqring_overflow_flush(struct io_ring_ctx *ctx)
{
	size_t cqe_size = sizeof(struct io_uring_cqe);

	if (__io_cqring_events(ctx) == ctx->cq_entries)
		return;

	if (ctx->flags & IORING_SETUP_CQE32)
		cqe_size <<= 1;

	io_cq_lock(ctx);
	while (!list_empty(&ctx->cq_overflow_list)) {
		struct io_uring_cqe *cqe;
		struct io_overflow_cqe *ocqe;

		if (!io_get_cqe_overflow(ctx, &cqe, true))
			break;
		ocqe = list_first_entry(&ctx->cq_overflow_list,
					struct io_overflow_cqe, list);
		memcpy(cqe, &ocqe->cqe, cqe_size);
		list_del(&ocqe->list);
		kfree(ocqe);
	}

	if (list_empty(&ctx->cq_overflow_list)) {
		clear_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq);
		atomic_andnot(IORING_SQ_CQ_OVERFLOW, &ctx->rings->sq_flags);
	}
	io_cq_unlock_post(ctx);
}

static void io_cqring_do_overflow_flush(struct io_ring_ctx *ctx)
{
	/* iopoll syncs against uring_lock, not completion_lock */
	if (ctx->flags & IORING_SETUP_IOPOLL)
		mutex_lock(&ctx->uring_lock);
	__io_cqring_overflow_flush(ctx);
	if (ctx->flags & IORING_SETUP_IOPOLL)
		mutex_unlock(&ctx->uring_lock);
}

static void io_cqring_overflow_flush(struct io_ring_ctx *ctx)
{
	if (test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq))
		io_cqring_do_overflow_flush(ctx);
}

/* can be called by any task */
static void io_put_task_remote(struct task_struct *task)
{
	struct io_uring_task *tctx = task->io_uring;

	percpu_counter_sub(&tctx->inflight, 1);
	if (unlikely(atomic_read(&tctx->in_cancel)))
		wake_up(&tctx->wait);
	put_task_struct(task);
}

/* used by a task to put its own references */
static void io_put_task_local(struct task_struct *task)
{
	task->io_uring->cached_refs++;
}

/* must to be called somewhat shortly after putting a request */
static inline void io_put_task(struct task_struct *task)
{
	if (likely(task == current))
		io_put_task_local(task);
	else
		io_put_task_remote(task);
}

void io_task_refs_refill(struct io_uring_task *tctx)
{
	unsigned int refill = -tctx->cached_refs + IO_TCTX_REFS_CACHE_NR;

	percpu_counter_add(&tctx->inflight, refill);
	refcount_add(refill, &current->usage);
	tctx->cached_refs += refill;
}

static __cold void io_uring_drop_tctx_refs(struct task_struct *task)
{
	struct io_uring_task *tctx = task->io_uring;
	unsigned int refs = tctx->cached_refs;

	if (refs) {
		tctx->cached_refs = 0;
		percpu_counter_sub(&tctx->inflight, refs);
		put_task_struct_many(task, refs);
	}
}

static bool io_cqring_event_overflow(struct io_ring_ctx *ctx, u64 user_data,
				     s32 res, u32 cflags, u64 extra1, u64 extra2)
{
	struct io_overflow_cqe *ocqe;
	size_t ocq_size = sizeof(struct io_overflow_cqe);
	bool is_cqe32 = (ctx->flags & IORING_SETUP_CQE32);

	lockdep_assert_held(&ctx->completion_lock);

	if (is_cqe32)
		ocq_size += sizeof(struct io_uring_cqe);

	ocqe = kmalloc(ocq_size, GFP_ATOMIC | __GFP_ACCOUNT);
	trace_io_uring_cqe_overflow(ctx, user_data, res, cflags, ocqe);
	if (!ocqe) {
		/*
		 * If we're in ring overflow flush mode, or in task cancel mode,
		 * or cannot allocate an overflow entry, then we need to drop it
		 * on the floor.
		 */
		io_account_cq_overflow(ctx);
		set_bit(IO_CHECK_CQ_DROPPED_BIT, &ctx->check_cq);
		return false;
	}
	if (list_empty(&ctx->cq_overflow_list)) {
		set_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq);
		atomic_or(IORING_SQ_CQ_OVERFLOW, &ctx->rings->sq_flags);

	}
	ocqe->cqe.user_data = user_data;
	ocqe->cqe.res = res;
	ocqe->cqe.flags = cflags;
	if (is_cqe32) {
		ocqe->cqe.big_cqe[0] = extra1;
		ocqe->cqe.big_cqe[1] = extra2;
	}
	list_add_tail(&ocqe->list, &ctx->cq_overflow_list);
	return true;
}

void io_req_cqe_overflow(struct io_kiocb *req)
{
	io_cqring_event_overflow(req->ctx, req->cqe.user_data,
				req->cqe.res, req->cqe.flags,
				req->big_cqe.extra1, req->big_cqe.extra2);
	memset(&req->big_cqe, 0, sizeof(req->big_cqe));
}

/*
 * writes to the cq entry need to come after reading head; the
 * control dependency is enough as we're using WRITE_ONCE to
 * fill the cq entry
 */
bool io_cqe_cache_refill(struct io_ring_ctx *ctx, bool overflow)
{
	struct io_rings *rings = ctx->rings;
	unsigned int off = ctx->cached_cq_tail & (ctx->cq_entries - 1);
	unsigned int free, queued, len;

	/*
	 * Posting into the CQ when there are pending overflowed CQEs may break
	 * ordering guarantees, which will affect links, F_MORE users and more.
	 * Force overflow the completion.
	 */
	if (!overflow && (ctx->check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT)))
		return false;

	/* userspace may cheat modifying the tail, be safe and do min */
	queued = min(__io_cqring_events(ctx), ctx->cq_entries);
	free = ctx->cq_entries - queued;
	/* we need a contiguous range, limit based on the current array offset */
	len = min(free, ctx->cq_entries - off);
	if (!len)
		return false;

	if (ctx->flags & IORING_SETUP_CQE32) {
		off <<= 1;
		len <<= 1;
	}

	ctx->cqe_cached = &rings->cqes[off];
	ctx->cqe_sentinel = ctx->cqe_cached + len;
	return true;
}

static bool io_fill_cqe_aux(struct io_ring_ctx *ctx, u64 user_data, s32 res,
			      u32 cflags)
{
	struct io_uring_cqe *cqe;

	ctx->cq_extra++;

	/*
	 * If we can't get a cq entry, userspace overflowed the
	 * submission (by quite a lot). Increment the overflow count in
	 * the ring.
	 */
	if (likely(io_get_cqe(ctx, &cqe))) {
		trace_io_uring_complete(ctx, NULL, user_data, res, cflags, 0, 0);

		WRITE_ONCE(cqe->user_data, user_data);
		WRITE_ONCE(cqe->res, res);
		WRITE_ONCE(cqe->flags, cflags);

		if (ctx->flags & IORING_SETUP_CQE32) {
			WRITE_ONCE(cqe->big_cqe[0], 0);
			WRITE_ONCE(cqe->big_cqe[1], 0);
		}
		return true;
	}
	return false;
}

static void __io_flush_post_cqes(struct io_ring_ctx *ctx)
	__must_hold(&ctx->uring_lock)
{
	struct io_submit_state *state = &ctx->submit_state;
	unsigned int i;

	lockdep_assert_held(&ctx->uring_lock);
	for (i = 0; i < state->cqes_count; i++) {
		struct io_uring_cqe *cqe = &ctx->completion_cqes[i];

		if (!io_fill_cqe_aux(ctx, cqe->user_data, cqe->res, cqe->flags)) {
			if (ctx->lockless_cq) {
				spin_lock(&ctx->completion_lock);
				io_cqring_event_overflow(ctx, cqe->user_data,
							cqe->res, cqe->flags, 0, 0);
				spin_unlock(&ctx->completion_lock);
			} else {
				io_cqring_event_overflow(ctx, cqe->user_data,
							cqe->res, cqe->flags, 0, 0);
			}
		}
	}
	state->cqes_count = 0;
}

static bool __io_post_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags,
			      bool allow_overflow)
{
	bool filled;

	io_cq_lock(ctx);
	filled = io_fill_cqe_aux(ctx, user_data, res, cflags);
	if (!filled && allow_overflow)
		filled = io_cqring_event_overflow(ctx, user_data, res, cflags, 0, 0);

	io_cq_unlock_post(ctx);
	return filled;
}

bool io_post_aux_cqe(struct io_ring_ctx *ctx, u64 user_data, s32 res, u32 cflags)
{
	return __io_post_aux_cqe(ctx, user_data, res, cflags, true);
}

/*
 * A helper for multishot requests posting additional CQEs.
 * Should only be used from a task_work including IO_URING_F_MULTISHOT.
 */
bool io_fill_cqe_req_aux(struct io_kiocb *req, bool defer, s32 res, u32 cflags)
{
	struct io_ring_ctx *ctx = req->ctx;
	u64 user_data = req->cqe.user_data;
	struct io_uring_cqe *cqe;

	lockdep_assert(!io_wq_current_is_worker());

	if (!defer)
		return __io_post_aux_cqe(ctx, user_data, res, cflags, false);

	lockdep_assert_held(&ctx->uring_lock);

	if (ctx->submit_state.cqes_count == ARRAY_SIZE(ctx->completion_cqes)) {
		__io_cq_lock(ctx);
		__io_flush_post_cqes(ctx);
		/* no need to flush - flush is deferred */
		__io_cq_unlock_post(ctx);
	}

	/* For defered completions this is not as strict as it is otherwise,
	 * however it's main job is to prevent unbounded posted completions,
	 * and in that it works just as well.
	 */
	if (test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq))
		return false;

	cqe = &ctx->completion_cqes[ctx->submit_state.cqes_count++];
	cqe->user_data = user_data;
	cqe->res = res;
	cqe->flags = cflags;
	return true;
}

static void __io_req_complete_post(struct io_kiocb *req, unsigned issue_flags)
{
	struct io_ring_ctx *ctx = req->ctx;
	struct io_rsrc_node *rsrc_node = NULL;

	io_cq_lock(ctx);
	if (!(req->flags & REQ_F_CQE_SKIP)) {
		if (!io_fill_cqe_req(ctx, req))
			io_req_cqe_overflow(req);
	}

	/*
	 * If we're the last reference to this request, add to our locked
	 * free_list cache.
	 */
	if (req_ref_put_and_test(req)) {
		if (req->flags & IO_REQ_LINK_FLAGS) {
			if (req->flags & IO_DISARM_MASK)
				io_disarm_next(req);
			if (req->link) {
				io_req_task_queue(req->link);
				req->link = NULL;
			}
		}
		io_put_kbuf_comp(req);
		if (unlikely(req->flags & IO_REQ_CLEAN_FLAGS))
			io_clean_op(req);
		io_put_file(req);

		rsrc_node = req->rsrc_node;
		/*
		 * Selected buffer deallocation in io_clean_op() assumes that
		 * we don't hold ->completion_lock. Clean them here to avoid
		 * deadlocks.
		 */
		io_put_task_remote(req->task);
		wq_list_add_head(&req->comp_list, &ctx->locked_free_list);
		ctx->locked_free_nr++;
	}
	io_cq_unlock_post(ctx);

	if (rsrc_node) {
		io_ring_submit_lock(ctx, issue_flags);
		io_put_rsrc_node(ctx, rsrc_node);
		io_ring_submit_unlock(ctx, issue_flags);
	}
}

void io_req_complete_post(struct io_kiocb *req, unsigned issue_flags)
{
	struct io_ring_ctx *ctx = req->ctx;

	if (ctx->task_complete && ctx->submitter_task != current) {
		req->io_task_work.func = io_req_task_complete;
		io_req_task_work_add(req);
	} else if (!(issue_flags & IO_URING_F_UNLOCKED) ||
		   !(ctx->flags & IORING_SETUP_IOPOLL)) {
		__io_req_complete_post(req, issue_flags);
	} else {
		mutex_lock(&ctx->uring_lock);
		__io_req_complete_post(req, issue_flags & ~IO_URING_F_UNLOCKED);
		mutex_unlock(&ctx->uring_lock);
	}
}

void io_req_defer_failed(struct io_kiocb *req, s32 res)
	__must_hold(&ctx->uring_lock)
{
	const struct io_cold_def *def = &io_cold_defs[req->opcode];

	lockdep_assert_held(&req->ctx->uring_lock);

	req_set_fail(req);
	io_req_set_res(req, res, io_put_kbuf(req, IO_URING_F_UNLOCKED));
	if (def->fail)
		def->fail(req);
	io_req_complete_defer(req);
}

/*
 * Don't initialise the fields below on every allocation, but do that in
 * advance and keep them valid across allocations.
 */
static void io_preinit_req(struct io_kiocb *req, struct io_ring_ctx *ctx)
{
	req->ctx = ctx;
	req->link = NULL;
	req->async_data = NULL;
	/* not necessary, but safer to zero */
	memset(&req->cqe, 0, sizeof(req->cqe));
	memset(&req->big_cqe, 0, sizeof(req->big_cqe));
}

static void io_flush_cached_locked_reqs(struct io_ring_ctx *ctx,
					struct io_submit_state *state)
{
	spin_lock(&ctx->completion_lock);
	wq_list_splice(&ctx->locked_free_list, &state->free_list);
	ctx->locked_free_nr = 0;
	spin_unlock(&ctx->completion_lock);
}

/*
 * A request might get retired back into the request caches even before opcode
 * handlers and io_issue_sqe() are done with it, e.g. inline completion path.
 * Because of that, io_alloc_req() should be called only under ->uring_lock
 * and with extra caution to not get a request that is still worked on.
 */
__cold bool __io_alloc_req_refill(struct io_ring_ctx *ctx)
	__must_hold(&ctx->uring_lock)
{
	gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;
	void *reqs[IO_REQ_ALLOC_BATCH];
	int ret, i;

	/*
	 * If we have more than a batch's worth of requests in our IRQ side
	 * locked cache, grab the lock and move them over to our submission
	 * side cache.
	 */
	if (data_race(ctx->locked_free_nr) > IO_COMPL_BATCH) {
		io_flush_cached_locked_reqs(ctx, &ctx->submit_state);
		if (!io_req_cache_empty(ctx))
			return true;
	}

	ret = kmem_cache_alloc_bulk(req_cachep, gfp, ARRAY_SIZE(reqs), reqs);

	/*
	 * Bulk alloc is all-or-nothing. If we fail to get a batch,
	 * retry single alloc to be on the safe side.
	 */
	if (unlikely(ret <= 0)) {
		reqs[0] = kmem_cache_alloc(req_cachep, gfp);
		if (!reqs[0])
			return false;
		ret = 1;
	}

	percpu_ref_get_many(&ctx->refs, ret);
	for (i = 0; i < ret; i++) {
		struct io_kiocb *req = reqs[i];

		io_preinit_req(req, ctx);
		io_req_add_to_cache(req, ctx);
	}
	return true;
}

__cold void io_free_req(struct io_kiocb *req)
{
	/* refs were already put, restore them for io_req_task_complete() */
	req->flags &= ~REQ_F_REFCOUNT;
	/* we only want to free it, don't post CQEs */
	req->flags |= REQ_F_CQE_SKIP;
	req->io_task_work.func = io_req_task_complete;
	io_req_task_work_add(req);
}

static void __io_req_find_next_prep(struct io_kiocb *req)
{
	struct io_ring_ctx *ctx = req->ctx;

	spin_lock(&ctx->completion_lock);
	io_disarm_next(req);
	spin_unlock(&ctx->completion_lock);
}

static inline struct io_kiocb *io_req_find_next(struct io_kiocb *req)
{
	struct io_kiocb *nxt;

	/*
	 * If LINK is set, we have dependent requests in this chain. If we
	 * didn't fail this request, queue the first one up, moving any other
	 * dependencies to the next request. In case of failure, fail the rest
	 * of the chain.
	 */
	if (unlikely(req->flags & IO_DISARM_MASK))
		__io_req_find_next_prep(req);
	nxt = req->link;
	req->link = NULL;
	return nxt;
}

static void ctx_flush_and_put(struct io_ring_ctx *ctx, struct io_tw_state *ts)
{
	if (!ctx)
		return;
	if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
		atomic_andnot(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
	if (ts->locked) {
		io_submit_flush_completions(ctx);
		mutex_unlock(&ctx->uring_lock);
		ts->locked = false;
	}
	percpu_ref_put(&ctx->refs);
}

/*
 * Run queued task_work, returning the number of entries processed in *count.
 * If more entries than max_entries are available, stop processing once this
 * is reached and return the rest of the list.
 */
struct llist_node *io_handle_tw_list(struct llist_node *node,
				     unsigned int *count,
				     unsigned int max_entries)
{
	struct io_ring_ctx *ctx = NULL;
	struct io_tw_state ts = { };

	do {
		struct llist_node *next = node->next;
		struct io_kiocb *req = container_of(node, struct io_kiocb,
						    io_task_work.node);

		if (req->ctx != ctx) {
			ctx_flush_and_put(ctx, &ts);
			ctx = req->ctx;
			/* if not contended, grab and improve batching */
			ts.locked = mutex_trylock(&ctx->uring_lock);
			percpu_ref_get(&ctx->refs);
		}
		INDIRECT_CALL_2(req->io_task_work.func,
				io_poll_task_func, io_req_rw_complete,
				req, &ts);
		node = next;
		(*count)++;
		if (unlikely(need_resched())) {
			ctx_flush_and_put(ctx, &ts);
			ctx = NULL;
			cond_resched();
		}
	} while (node && *count < max_entries);

	ctx_flush_and_put(ctx, &ts);
	return node;
}

/**
 * io_llist_xchg - swap all entries in a lock-less list
 * @head:	the head of lock-less list to delete all entries
 * @new:	new entry as the head of the list
 *
 * If list is empty, return NULL, otherwise, return the pointer to the first entry.
 * The order of entries returned is from the newest to the oldest added one.
 */
static inline struct llist_node *io_llist_xchg(struct llist_head *head,
					       struct llist_node *new)
{
	return xchg(&head->first, new);
}

static __cold void io_fallback_tw(struct io_uring_task *tctx, bool sync)
{
	struct llist_node *node = llist_del_all(&tctx->task_list);
	struct io_ring_ctx *last_ctx = NULL;
	struct io_kiocb *req;

	while (node) {
		req = container_of(node, struct io_kiocb, io_task_work.node);
		node = node->next;
		if (sync && last_ctx != req->ctx) {
			if (last_ctx) {
				flush_delayed_work(&last_ctx->fallback_work);
				percpu_ref_put(&last_ctx->refs);
			}
			last_ctx = req->ctx;
			percpu_ref_get(&last_ctx->refs);
		}
		if (llist_add(&req->io_task_work.node,
			      &req->ctx->fallback_llist))
			schedule_delayed_work(&req->ctx->fallback_work, 1);
	}

	if (last_ctx) {
		flush_delayed_work(&last_ctx->fallback_work);
		percpu_ref_put(&last_ctx->refs);
	}
}

struct llist_node *tctx_task_work_run(struct io_uring_task *tctx,
				      unsigned int max_entries,
				      unsigned int *count)
{
	struct llist_node *node;

	if (unlikely(current->flags & PF_EXITING)) {
		io_fallback_tw(tctx, true);
		return NULL;
	}

	node = llist_del_all(&tctx->task_list);
	if (node) {
		node = llist_reverse_order(node);
		node = io_handle_tw_list(node, count, max_entries);
	}

	/* relaxed read is enough as only the task itself sets ->in_cancel */
	if (unlikely(atomic_read(&tctx->in_cancel)))
		io_uring_drop_tctx_refs(current);

	trace_io_uring_task_work_run(tctx, *count);
	return node;
}

void tctx_task_work(struct callback_head *cb)
{
	struct io_uring_task *tctx;
	struct llist_node *ret;
	unsigned int count = 0;

	tctx = container_of(cb, struct io_uring_task, task_work);
	ret = tctx_task_work_run(tctx, UINT_MAX, &count);
	/* can't happen */
	WARN_ON_ONCE(ret);
}

static inline void io_req_local_work_add(struct io_kiocb *req, unsigned flags)
{
	struct io_ring_ctx *ctx = req->ctx;
	unsigned nr_wait, nr_tw, nr_tw_prev;
	struct llist_node *head;

	/* See comment above IO_CQ_WAKE_INIT */
	BUILD_BUG_ON(IO_CQ_WAKE_FORCE <= IORING_MAX_CQ_ENTRIES);

	/*
	 * We don't know how many reuqests is there in the link and whether
	 * they can even be queued lazily, fall back to non-lazy.
	 */
	if (req->flags & (REQ_F_LINK | REQ_F_HARDLINK))
		flags &= ~IOU_F_TWQ_LAZY_WAKE;

	head = READ_ONCE(ctx->work_llist.first);
	do {
		nr_tw_prev = 0;
		if (head) {
			struct io_kiocb *first_req = container_of(head,
							struct io_kiocb,
							io_task_work.node);
			/*
			 * Might be executed at any moment, rely on
			 * SLAB_TYPESAFE_BY_RCU to keep it alive.
			 */
			nr_tw_prev = READ_ONCE(first_req->nr_tw);
		}

		/*
		 * Theoretically, it can overflow, but that's fine as one of
		 * previous adds should've tried to wake the task.
		 */
		nr_tw = nr_tw_prev + 1;
		if (!(flags & IOU_F_TWQ_LAZY_WAKE))
			nr_tw = IO_CQ_WAKE_FORCE;

		req->nr_tw = nr_tw;
		req->io_task_work.node.next = head;
	} while (!try_cmpxchg(&ctx->work_llist.first, &head,
			      &req->io_task_work.node));

	/*
	 * cmpxchg implies a full barrier, which pairs with the barrier
	 * in set_current_state() on the io_cqring_wait() side. It's used
	 * to ensure that either we see updated ->cq_wait_nr, or waiters
	 * going to sleep will observe the work added to the list, which
	 * is similar to the wait/wawke task state sync.
	 */

	if (!head) {
		if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
			atomic_or(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
		if (ctx->has_evfd)
			io_eventfd_signal(ctx);
	}

	nr_wait = atomic_read(&ctx->cq_wait_nr);
	/* not enough or no one is waiting */
	if (nr_tw < nr_wait)
		return;
	/* the previous add has already woken it up */
	if (nr_tw_prev >= nr_wait)
		return;
	wake_up_state(ctx->submitter_task, TASK_INTERRUPTIBLE);
}

static void io_req_normal_work_add(struct io_kiocb *req)
{
	struct io_uring_task *tctx = req->task->io_uring;
	struct io_ring_ctx *ctx = req->ctx;

	/* task_work already pending, we're done */
	if (!llist_add(&req->io_task_work.node, &tctx->task_list))
		return;

	if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
		atomic_or(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);

	/* SQPOLL doesn't need the task_work added, it'll run it itself */
	if (ctx->flags & IORING_SETUP_SQPOLL) {
		struct io_sq_data *sqd = ctx->sq_data;

		if (sqd->thread)
			__set_notify_signal(sqd->thread);
		return;
	}

	if (likely(!task_work_add(req->task, &tctx->task_work, ctx->notify_method)))
		return;

	io_fallback_tw(tctx, false);
}

void __io_req_task_work_add(struct io_kiocb *req, unsigned flags)
{
	if (req->ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
		rcu_read_lock();
		io_req_local_work_add(req, flags);
		rcu_read_unlock();
	} else {
		io_req_normal_work_add(req);
	}
}

static void __cold io_move_task_work_from_local(struct io_ring_ctx *ctx)
{
	struct llist_node *node;

	node = llist_del_all(&ctx->work_llist);
	while (node) {
		struct io_kiocb *req = container_of(node, struct io_kiocb,
						    io_task_work.node);

		node = node->next;
		io_req_normal_work_add(req);
	}
}

static bool io_run_local_work_continue(struct io_ring_ctx *ctx, int events,
				       int min_events)
{
	if (llist_empty(&ctx->work_llist))
		return false;
	if (events < min_events)
		return true;
	if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
		atomic_or(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
	return false;
}

static int __io_run_local_work(struct io_ring_ctx *ctx, struct io_tw_state *ts,
			       int min_events)
{
	struct llist_node *node;
	unsigned int loops = 0;
	int ret = 0;

	if (WARN_ON_ONCE(ctx->submitter_task != current))
		return -EEXIST;
	if (ctx->flags & IORING_SETUP_TASKRUN_FLAG)
		atomic_andnot(IORING_SQ_TASKRUN, &ctx->rings->sq_flags);
again:
	/*
	 * llists are in reverse order, flip it back the right way before
	 * running the pending items.
	 */
	node = llist_reverse_order(io_llist_xchg(&ctx->work_llist, NULL));
	while (node) {
		struct llist_node *next = node->next;
		struct io_kiocb *req = container_of(node, struct io_kiocb,
						    io_task_work.node);
		INDIRECT_CALL_2(req->io_task_work.func,
				io_poll_task_func, io_req_rw_complete,
				req, ts);
		ret++;
		node = next;
	}
	loops++;

	if (io_run_local_work_continue(ctx, ret, min_events))
		goto again;
	if (ts->locked) {
		io_submit_flush_completions(ctx);
		if (io_run_local_work_continue(ctx, ret, min_events))
			goto again;
	}

	trace_io_uring_local_work_run(ctx, ret, loops);
	return ret;
}

static inline int io_run_local_work_locked(struct io_ring_ctx *ctx,
					   int min_events)
{
	struct io_tw_state ts = { .locked = true, };
	int ret;

	if (llist_empty(&ctx->work_llist))
		return 0;

	ret = __io_run_local_work(ctx, &ts, min_events);
	/* shouldn't happen! */
	if (WARN_ON_ONCE(!ts.locked))
		mutex_lock(&ctx->uring_lock);
	return ret;
}

static int io_run_local_work(struct io_ring_ctx *ctx, int min_events)
{
	struct io_tw_state ts = {};
	int ret;

	ts.locked = mutex_trylock(&ctx->uring_lock);
	ret = __io_run_local_work(ctx, &ts, min_events);
	if (ts.locked)
		mutex_unlock(&ctx->uring_lock);

	return ret;
}

static void io_req_task_cancel(struct io_kiocb *req, struct io_tw_state *ts)
{
	io_tw_lock(req->ctx, ts);
	io_req_defer_failed(req, req->cqe.res);
}

void io_req_task_submit(struct io_kiocb *req, struct io_tw_state *ts)
{
	io_tw_lock(req->ctx, ts);
	/* req->task == current here, checking PF_EXITING is safe */
	if (unlikely(req->task->flags & PF_EXITING))
		io_req_defer_failed(req, -EFAULT);
	else if (req->flags & REQ_F_FORCE_ASYNC)
		io_queue_iowq(req, ts);
	else
		io_queue_sqe(req);
}

void io_req_task_queue_fail(struct io_kiocb *req, int ret)
{
	io_req_set_res(req, ret, 0);
	req->io_task_work.func = io_req_task_cancel;
	io_req_task_work_add(req);
}

void io_req_task_queue(struct io_kiocb *req)
{
	req->io_task_work.func = io_req_task_submit;
	io_req_task_work_add(req);
}

void io_queue_next(struct io_kiocb *req)
{
	struct io_kiocb *nxt = io_req_find_next(req);

	if (nxt)
		io_req_task_queue(nxt);
}

static void io_free_batch_list(struct io_ring_ctx *ctx,
			       struct io_wq_work_node *node)
	__must_hold(&ctx->uring_lock)
{
	do {
		struct io_kiocb *req = container_of(node, struct io_kiocb,
						    comp_list);

		if (unlikely(req->flags & IO_REQ_CLEAN_SLOW_FLAGS)) {
			if (req->flags & REQ_F_REFCOUNT) {
				node = req->comp_list.next;
				if (!req_ref_put_and_test(req))
					continue;
			}
			if ((req->flags & REQ_F_POLLED) && req->apoll) {
				struct async_poll *apoll = req->apoll;

				if (apoll->double_poll)
					kfree(apoll->double_poll);
				if (!io_alloc_cache_put(&ctx->apoll_cache, &apoll->cache))
					kfree(apoll);
				req->flags &= ~REQ_F_POLLED;
			}
			if (req->flags & IO_REQ_LINK_FLAGS)
				io_queue_next(req);
			if (unlikely(req->flags & IO_REQ_CLEAN_FLAGS))
				io_clean_op(req);
		}
		io_put_file(req);

		io_req_put_rsrc_locked(req, ctx);

		io_put_task(req->task);
		node = req->comp_list.next;
		io_req_add_to_cache(req, ctx);
	} while (node);
}

void __io_submit_flush_completions(struct io_ring_ctx *ctx)
	__must_hold(&ctx->uring_lock)
{
	struct io_submit_state *state = &ctx->submit_state;
	struct io_wq_work_node *node;

	__io_cq_lock(ctx);
	/* must come first to preserve CQE ordering in failure cases */
	if (state->cqes_count)
		__io_flush_post_cqes(ctx);
	__wq_list_for_each(node, &state->compl_reqs) {
		struct io_kiocb *req = container_of(node, struct io_kiocb,
					    comp_list);

		if (!(req->flags & REQ_F_CQE_SKIP) &&
		    unlikely(!io_fill_cqe_req(ctx, req))) {
			if (ctx->lockless_cq) {
				spin_lock(&ctx->completion_lock);
				io_req_cqe_overflow(req);
				spin_unlock(&ctx->completion_lock);
			} else {
				io_req_cqe_overflow(req);
			}
		}
	}
	__io_cq_unlock_post(ctx);

	if (!wq_list_empty(&ctx->submit_state.compl_reqs)) {
		io_free_batch_list(ctx, state->compl_reqs.first);
		INIT_WQ_LIST(&state->compl_reqs);
	}
}

static unsigned io_cqring_events(struct io_ring_ctx *ctx)
{
	/* See comment at the top of this file */
	smp_rmb();
	return __io_cqring_events(ctx);
}

/*
 * We can't just wait for polled events to come to us, we have to actively
 * find and complete them.
 */
static __cold void io_iopoll_try_reap_events(struct io_ring_ctx *ctx)
{
	if (!(ctx->flags & IORING_SETUP_IOPOLL))
		return;

	mutex_lock(&ctx->uring_lock);
	while (!wq_list_empty(&ctx->iopoll_list)) {
		/* let it sleep and repeat later if can't complete a request */
		if (io_do_iopoll(ctx, true) == 0)
			break;
		/*
		 * Ensure we allow local-to-the-cpu processing to take place,
		 * in this case we need to ensure that we reap all events.
		 * Also let task_work, etc. to progress by releasing the mutex
		 */
		if (need_resched()) {
			mutex_unlock(&ctx->uring_lock);
			cond_resched();
			mutex_lock(&ctx->uring_lock);
		}
	}
	mutex_unlock(&ctx->uring_lock);
}

static int io_iopoll_check(struct io_ring_ctx *ctx, long min)
{
	unsigned int nr_events = 0;
	unsigned long check_cq;

	if (!io_allowed_run_tw(ctx))
		return -EEXIST;

	check_cq = READ_ONCE(ctx->check_cq);
	if (unlikely(check_cq)) {
		if (check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT))
			__io_cqring_overflow_flush(ctx);
		/*
		 * Similarly do not spin if we have not informed the user of any
		 * dropped CQE.
		 */
		if (check_cq & BIT(IO_CHECK_CQ_DROPPED_BIT))
			return -EBADR;
	}
	/*
	 * Don't enter poll loop if we already have events pending.
	 * If we do, we can potentially be spinning for commands that
	 * already triggered a CQE (eg in error).
	 */
	if (io_cqring_events(ctx))
		return 0;

	do {
		int ret = 0;

		/*
		 * If a submit got punted to a workqueue, we can have the
		 * application entering polling for a command before it gets
		 * issued. That app will hold the uring_lock for the duration
		 * of the poll right here, so we need to take a breather every
		 * now and then to ensure that the issue has a chance to add
		 * the poll to the issued list. Otherwise we can spin here
		 * forever, while the workqueue is stuck trying to acquire the
		 * very same mutex.
		 */
		if (wq_list_empty(&ctx->iopoll_list) ||
		    io_task_work_pending(ctx)) {
			u32 tail = ctx->cached_cq_tail;

			(void) io_run_local_work_locked(ctx, min);

			if (task_work_pending(current) ||
			    wq_list_empty(&ctx->iopoll_list)) {
				mutex_unlock(&ctx->uring_lock);
				io_run_task_work();
				mutex_lock(&ctx->uring_lock);
			}
			/* some requests don't go through iopoll_list */
			if (tail != ctx->cached_cq_tail ||
			    wq_list_empty(&ctx->iopoll_list))
				break;
		}
		ret = io_do_iopoll(ctx, !min);
		if (unlikely(ret < 0))
			return ret;

		if (task_sigpending(current))
			return -EINTR;
		if (need_resched())
			break;

		nr_events += ret;
	} while (nr_events < min);

	return 0;
}

void io_req_task_complete(struct io_kiocb *req, struct io_tw_state *ts)
{
	if (ts->locked)
		io_req_complete_defer(req);
	else
		io_req_complete_post(req, IO_URING_F_UNLOCKED);
}

/*
 * After the iocb has been issued, it's safe to be found on the poll list.
 * Adding the kiocb to the list AFTER submission ensures that we don't
 * find it from a io_do_iopoll() thread before the issuer is done
 * accessing the kiocb cookie.
 */
static void io_iopoll_req_issued(struct io_kiocb *req, unsigned int issue_flags)
{
	struct io_ring_ctx *ctx = req->ctx;
	const bool needs_lock = issue_flags & IO_URING_F_UNLOCKED;

	/* workqueue context doesn't hold uring_lock, grab it now */
	if (unlikely(needs_lock))
		mutex_lock(&ctx->uring_lock);

	/*
	 * Track whether we have multiple files in our lists. This will impact
	 * how we do polling eventually, not spinning if we're on potentially
	 * different devices.
	 */
	if (wq_list_empty(&ctx->iopoll_list)) {
		ctx->poll_multi_queue = false;
	} else if (!ctx->poll_multi_queue) {
		struct io_kiocb *list_req;

		list_req = container_of(ctx->iopoll_list.first, struct io_kiocb,
					comp_list);
		if (list_req->file != req->file)
			ctx->poll_multi_queue = true;
	}

	/*
	 * For fast devices, IO may have already completed. If it has, add
	 * it to the front so we find it first.
	 */
	if (READ_ONCE(req->iopoll_completed))
		wq_list_add_head(&req->comp_list, &ctx->iopoll_list);
	else
		wq_list_add_tail(&req->comp_list, &ctx->iopoll_list);

	if (unlikely(needs_lock)) {
		/*
		 * If IORING_SETUP_SQPOLL is enabled, sqes are either handle
		 * in sq thread task context or in io worker task context. If
		 * current task context is sq thread, we don't need to check
		 * whether should wake up sq thread.
		 */
		if ((ctx->flags & IORING_SETUP_SQPOLL) &&
		    wq_has_sleeper(&ctx->sq_data->wait))
			wake_up(&ctx->sq_data->wait);

		mutex_unlock(&ctx->uring_lock);
	}
}

io_req_flags_t io_file_get_flags(struct file *file)
{
	io_req_flags_t res = 0;

	if (S_ISREG(file_inode(file)->i_mode))
		res |= REQ_F_ISREG;
	if ((file->f_flags & O_NONBLOCK) || (file->f_mode & FMODE_NOWAIT))
		res |= REQ_F_SUPPORT_NOWAIT;
	return res;
}

bool io_alloc_async_data(struct io_kiocb *req)
{
	WARN_ON_ONCE(!io_cold_defs[req->opcode].async_size);
	req->async_data = kmalloc(io_cold_defs[req->opcode].async_size, GFP_KERNEL);
	if (req->async_data) {
		req->flags |= REQ_F_ASYNC_DATA;
		return false;
	}
	return true;
}

int io_req_prep_async(struct io_kiocb *req)
{
	const struct io_cold_def *cdef = &io_cold_defs[req->opcode];
	const struct io_issue_def *def = &io_issue_defs[req->opcode];

	/* assign early for deferred execution for non-fixed file */
	if (def->needs_file && !(req->flags & REQ_F_FIXED_FILE) && !req->file)
		req->file = io_file_get_normal(req, req->cqe.fd);
	if (!cdef->prep_async)
		return 0;
	if (WARN_ON_ONCE(req_has_async_data(req)))
		return -EFAULT;
	if (!def->manual_alloc) {
		if (io_alloc_async_data(req))
			return -EAGAIN;
	}
	return cdef->prep_async(req);
}

static u32 io_get_sequence(struct io_kiocb *req)
{
	u32 seq = req->ctx->cached_sq_head;
	struct io_kiocb *cur;

	/* need original cached_sq_head, but it was increased for each req */
	io_for_each_link(cur, req)
		seq--;
	return seq;
}

static __cold void io_drain_req(struct io_kiocb *req)
	__must_hold(&ctx->uring_lock)
{
	struct io_ring_ctx *ctx = req->ctx;
	struct io_defer_entry *de;
	int ret;
	u32 seq = io_get_sequence(req);

	/* Still need defer if there is pending req in defer list. */
	spin_lock(&ctx->completion_lock);
	if (!req_need_defer(req, seq) && list_empty_careful(&ctx->defer_list)) {
		spin_unlock(&ctx->completion_lock);
queue:
		ctx->drain_active = false;
		io_req_task_queue(req);
		return;
	}
	spin_unlock(&ctx->completion_lock);

	io_prep_async_link(req);
	de = kmalloc(sizeof(*de), GFP_KERNEL);
	if (!de) {
		ret = -ENOMEM;
		io_req_defer_failed(req, ret);
		return;
	}

	spin_lock(&ctx->completion_lock);
	if (!req_need_defer(req, seq) && list_empty(&ctx->defer_list)) {
		spin_unlock(&ctx->completion_lock);
		kfree(de);
		goto queue;
	}

	trace_io_uring_defer(req);
	de->req = req;
	de->seq = seq;
	list_add_tail(&de->list, &ctx->defer_list);
	spin_unlock(&ctx->completion_lock);
}

static bool io_assign_file(struct io_kiocb *req, const struct io_issue_def *def,
			   unsigned int issue_flags)
{
	if (req->file || !def->needs_file)
		return true;

	if (req->flags & REQ_F_FIXED_FILE)
		req->file = io_file_get_fixed(req, req->cqe.fd, issue_flags);
	else
		req->file = io_file_get_normal(req, req->cqe.fd);

	return !!req->file;
}

static int io_issue_sqe(struct io_kiocb *req, unsigned int issue_flags)
{
	const struct io_issue_def *def = &io_issue_defs[req->opcode];
	const struct cred *creds = NULL;
	int ret;

	if (unlikely(!io_assign_file(req, def, issue_flags)))
		return -EBADF;

	if (unlikely((req->flags & REQ_F_CREDS) && req->creds != current_cred()))
		creds = override_creds(req->creds);

	if (!def->audit_skip)
		audit_uring_entry(req->opcode);

	ret = def->issue(req, issue_flags);

	if (!def->audit_skip)
		audit_uring_exit(!ret, ret);

	if (creds)
		revert_creds(creds);

	if (ret == IOU_OK) {
		if (issue_flags & IO_URING_F_COMPLETE_DEFER)
			io_req_complete_defer(req);
		else
			io_req_complete_post(req, issue_flags);

		return 0;
	}

	if (ret == IOU_ISSUE_SKIP_COMPLETE) {
		ret = 0;
		io_arm_ltimeout(req);

		/* If the op doesn't have a file, we're not polling for it */
		if ((req->ctx->flags & IORING_SETUP_IOPOLL) && def->iopoll_queue)
			io_iopoll_req_issued(req, issue_flags);
	}
	return ret;
}

int io_poll_issue(struct io_kiocb *req, struct io_tw_state *ts)
{
	io_tw_lock(req->ctx, ts);
	return io_issue_sqe(req, IO_URING_F_NONBLOCK|IO_URING_F_MULTISHOT|
				 IO_URING_F_COMPLETE_DEFER);
}

struct io_wq_work *io_wq_free_work(struct io_wq_work *work)
{
	struct io_kiocb *req = container_of(work, struct io_kiocb, work);
	struct io_kiocb *nxt = NULL;

	if (req_ref_put_and_test(req)) {
		if (req->flags & IO_REQ_LINK_FLAGS)
			nxt = io_req_find_next(req);
		io_free_req(req);
	}
	return nxt ? &nxt->work : NULL;
}

void io_wq_submit_work(struct io_wq_work *work)
{
	struct io_kiocb *req = container_of(work, struct io_kiocb, work);
	const struct io_issue_def *def = &io_issue_defs[req->opcode];
	unsigned int issue_flags = IO_URING_F_UNLOCKED | IO_URING_F_IOWQ;
	bool needs_poll = false;
	int ret = 0, err = -ECANCELED;

	/* one will be dropped by ->io_wq_free_work() after returning to io-wq */
	if (!(req->flags & REQ_F_REFCOUNT))
		__io_req_set_refcount(req, 2);
	else
		req_ref_get(req);

	io_arm_ltimeout(req);

	/* either cancelled or io-wq is dying, so don't touch tctx->iowq */
	if (work->flags & IO_WQ_WORK_CANCEL) {
fail:
		io_req_task_queue_fail(req, err);
		return;
	}
	if (!io_assign_file(req, def, issue_flags)) {
		err = -EBADF;
		work->flags |= IO_WQ_WORK_CANCEL;
		goto fail;
	}

	/*
	 * If DEFER_TASKRUN is set, it's only allowed to post CQEs from the
	 * submitter task context. Final request completions are handed to the
	 * right context, however this is not the case of auxiliary CQEs,
	 * which is the main mean of operation for multishot requests.
	 * Don't allow any multishot execution from io-wq. It's more restrictive
	 * than necessary and also cleaner.
	 */
	if (req->flags & REQ_F_APOLL_MULTISHOT) {
		err = -EBADFD;
		if (!io_file_can_poll(req))
			goto fail;
		if (req->file->f_flags & O_NONBLOCK ||
		    req->file->f_mode & FMODE_NOWAIT) {
			err = -ECANCELED;
			if (io_arm_poll_handler(req, issue_flags) != IO_APOLL_OK)
				goto fail;
			return;
		} else {
			req->flags &= ~REQ_F_APOLL_MULTISHOT;
		}
	}

	if (req->flags & REQ_F_FORCE_ASYNC) {
		bool opcode_poll = def->pollin || def->pollout;

		if (opcode_poll && io_file_can_poll(req)) {
			needs_poll = true;
			issue_flags |= IO_URING_F_NONBLOCK;
		}
	}

	do {
		ret = io_issue_sqe(req, issue_flags);
		if (ret != -EAGAIN)
			break;

		/*
		 * If REQ_F_NOWAIT is set, then don't wait or retry with
		 * poll. -EAGAIN is final for that case.
		 */
		if (req->flags & REQ_F_NOWAIT)
			break;

		/*
		 * We can get EAGAIN for iopolled IO even though we're
		 * forcing a sync submission from here, since we can't
		 * wait for request slots on the block side.
		 */
		if (!needs_poll) {
			if (!(req->ctx->flags & IORING_SETUP_IOPOLL))
				break;
			if (io_wq_worker_stopped())
				break;
			cond_resched();
			continue;
		}

		if (io_arm_poll_handler(req, issue_flags) == IO_APOLL_OK)
			return;
		/* aborted or ready, in either case retry blocking */
		needs_poll = false;
		issue_flags &= ~IO_URING_F_NONBLOCK;
	} while (1);

	/* avoid locking problems by failing it from a clean context */
	if (ret < 0)
		io_req_task_queue_fail(req, ret);
}

inline struct file *io_file_get_fixed(struct io_kiocb *req, int fd,
				      unsigned int issue_flags)
{
	struct io_ring_ctx *ctx = req->ctx;
	struct io_fixed_file *slot;
	struct file *file = NULL;

	io_ring_submit_lock(ctx, issue_flags);

	if (unlikely((unsigned int)fd >= ctx->nr_user_files))
		goto out;
	fd = array_index_nospec(fd, ctx->nr_user_files);
	slot = io_fixed_file_slot(&ctx->file_table, fd);
	if (!req->rsrc_node)
		__io_req_set_rsrc_node(req, ctx);
	req->flags |= io_slot_flags(slot);
	file = io_slot_file(slot);
out:
	io_ring_submit_unlock(ctx, issue_flags);
	return file;
}

struct file *io_file_get_normal(struct io_kiocb *req, int fd)
{
	struct file *file = fget(fd);

	trace_io_uring_file_get(req, fd);

	/* we don't allow fixed io_uring files */
	if (file && io_is_uring_fops(file))
		io_req_track_inflight(req);
	return file;
}

static void io_queue_async(struct io_kiocb *req, int ret)
	__must_hold(&req->ctx->uring_lock)
{
	struct io_kiocb *linked_timeout;

	if (ret != -EAGAIN || (req->flags & REQ_F_NOWAIT)) {
		io_req_defer_failed(req, ret);
		return;
	}

	linked_timeout = io_prep_linked_timeout(req);

	switch (io_arm_poll_handler(req, 0)) {
	case IO_APOLL_READY:
		io_kbuf_recycle(req, 0);
		io_req_task_queue(req);
		break;
	case IO_APOLL_ABORTED:
		io_kbuf_recycle(req, 0);
		io_queue_iowq(req, NULL);
		break;
	case IO_APOLL_OK:
		break;
	}

	if (linked_timeout)
		io_queue_linked_timeout(linked_timeout);
}

static inline void io_queue_sqe(struct io_kiocb *req)
	__must_hold(&req->ctx->uring_lock)
{
	int ret;

	ret = io_issue_sqe(req, IO_URING_F_NONBLOCK|IO_URING_F_COMPLETE_DEFER);

	/*
	 * We async punt it if the file wasn't marked NOWAIT, or if the file
	 * doesn't support non-blocking read/write attempts
	 */
	if (unlikely(ret))
		io_queue_async(req, ret);
}

static void io_queue_sqe_fallback(struct io_kiocb *req)
	__must_hold(&req->ctx->uring_lock)
{
	if (unlikely(req->flags & REQ_F_FAIL)) {
		/*
		 * We don't submit, fail them all, for that replace hardlinks
		 * with normal links. Extra REQ_F_LINK is tolerated.
		 */
		req->flags &= ~REQ_F_HARDLINK;
		req->flags |= REQ_F_LINK;
		io_req_defer_failed(req, req->cqe.res);
	} else {
		int ret = io_req_prep_async(req);

		if (unlikely(ret)) {
			io_req_defer_failed(req, ret);
			return;
		}

		if (unlikely(req->ctx->drain_active))
			io_drain_req(req);
		else
			io_queue_iowq(req, NULL);
	}
}

/*
 * Check SQE restrictions (opcode and flags).
 *
 * Returns 'true' if SQE is allowed, 'false' otherwise.
 */
static inline bool io_check_restriction(struct io_ring_ctx *ctx,
					struct io_kiocb *req,
					unsigned int sqe_flags)
{
	if (!test_bit(req->opcode, ctx->restrictions.sqe_op))
		return false;

	if ((sqe_flags & ctx->restrictions.sqe_flags_required) !=
	    ctx->restrictions.sqe_flags_required)
		return false;

	if (sqe_flags & ~(ctx->restrictions.sqe_flags_allowed |
			  ctx->restrictions.sqe_flags_required))
		return false;

	return true;
}

static void io_init_req_drain(struct io_kiocb *req)
{
	struct io_ring_ctx *ctx = req->ctx;
	struct io_kiocb *head = ctx->submit_state.link.head;

	ctx->drain_active = true;
	if (head) {
		/*
		 * If we need to drain a request in the middle of a link, drain
		 * the head request and the next request/link after the current
		 * link. Considering sequential execution of links,
		 * REQ_F_IO_DRAIN will be maintained for every request of our
		 * link.
		 */
		head->flags |= REQ_F_IO_DRAIN | REQ_F_FORCE_ASYNC;
		ctx->drain_next = true;
	}
}

static __cold int io_init_fail_req(struct io_kiocb *req, int err)
{
	/* ensure per-opcode data is cleared if we fail before prep */
	memset(&req->cmd.data, 0, sizeof(req->cmd.data));
	return err;
}

static int io_init_req(struct io_ring_ctx *ctx, struct io_kiocb *req,
		       const struct io_uring_sqe *sqe)
	__must_hold(&ctx->uring_lock)
{
	const struct io_issue_def *def;
	unsigned int sqe_flags;
	int personality;
	u8 opcode;

	/* req is partially pre-initialised, see io_preinit_req() */
	req->opcode = opcode = READ_ONCE(sqe->opcode);
	/* same numerical values with corresponding REQ_F_*, safe to copy */
	sqe_flags = READ_ONCE(sqe->flags);
	req->flags = (io_req_flags_t) sqe_flags;
	req->cqe.user_data = READ_ONCE(sqe->user_data);
	req->file = NULL;
	req->rsrc_node = NULL;
	req->task = current;
	req->cancel_seq_set = false;

	if (unlikely(opcode >= IORING_OP_LAST)) {
		req->opcode = 0;
		return io_init_fail_req(req, -EINVAL);
	}
	def = &io_issue_defs[opcode];
	if (unlikely(sqe_flags & ~SQE_COMMON_FLAGS)) {
		/* enforce forwards compatibility on users */
		if (sqe_flags & ~SQE_VALID_FLAGS)
			return io_init_fail_req(req, -EINVAL);
		if (sqe_flags & IOSQE_BUFFER_SELECT) {
			if (!def->buffer_select)
				return io_init_fail_req(req, -EOPNOTSUPP);
			req->buf_index = READ_ONCE(sqe->buf_group);
		}
		if (sqe_flags & IOSQE_CQE_SKIP_SUCCESS)
			ctx->drain_disabled = true;
		if (sqe_flags & IOSQE_IO_DRAIN) {
			if (ctx->drain_disabled)
				return io_init_fail_req(req, -EOPNOTSUPP);
			io_init_req_drain(req);
		}
	}
	if (unlikely(ctx->restricted || ctx->drain_active || ctx->drain_next)) {
		if (ctx->restricted && !io_check_restriction(ctx, req, sqe_flags))
			return io_init_fail_req(req, -EACCES);
		/* knock it to the slow queue path, will be drained there */
		if (ctx->drain_active)
			req->flags |= REQ_F_FORCE_ASYNC;
		/* if there is no link, we're at "next" request and need to drain */
		if (unlikely(ctx->drain_next) && !ctx->submit_state.link.head) {
			ctx->drain_next = false;
			ctx->drain_active = true;
			req->flags |= REQ_F_IO_DRAIN | REQ_F_FORCE_ASYNC;
		}
	}

	if (!def->ioprio && sqe->ioprio)
		return io_init_fail_req(req, -EINVAL);
	if (!def->iopoll && (ctx->flags & IORING_SETUP_IOPOLL))
		return io_init_fail_req(req, -EINVAL);

	if (def->needs_file) {
		struct io_submit_state *state = &ctx->submit_state;

		req->cqe.fd = READ_ONCE(sqe->fd);

		/*
		 * Plug now if we have more than 2 IO left after this, and the
		 * target is potentially a read/write to block based storage.
		 */
		if (state->need_plug && def->plug) {
			state->plug_started = true;
			state->need_plug = false;
			blk_start_plug_nr_ios(&state->plug, state->submit_nr);
		}
	}

	personality = READ_ONCE(sqe->personality);
	if (personality) {
		int ret;

		req->creds = xa_load(&ctx->personalities, personality);
		if (!req->creds)
			return io_init_fail_req(req, -EINVAL);
		get_cred(req->creds);
		ret = security_uring_override_creds(req->creds);
		if (ret) {
			put_cred(req->creds);
			return io_init_fail_req(req, ret);
		}
		req->flags |= REQ_F_CREDS;
	}

	return def->prep(req, sqe);
}

static __cold int io_submit_fail_init(const struct io_uring_sqe *sqe,
				      struct io_kiocb *req, int ret)
{
	struct io_ring_ctx *ctx = req->ctx;
	struct io_submit_link *link = &ctx->submit_state.link;
	struct io_kiocb *head = link->head;

	trace_io_uring_req_failed(sqe, req, ret);

	/*
	 * Avoid breaking links in the middle as it renders links with SQPOLL
	 * unusable. Instead of failing eagerly, continue assembling the link if
	 * applicable and mark the head with REQ_F_FAIL. The link flushing code
	 * should find the flag and handle the rest.
	 */
	req_fail_link_node(req, ret);
	if (head && !(head->flags & REQ_F_FAIL))
		req_fail_link_node(head, -ECANCELED);

	if (!(req->flags & IO_REQ_LINK_FLAGS)) {
		if (head) {
			link->last->link = req;
			link->head = NULL;
			req = head;
		}
		io_queue_sqe_fallback(req);
		return ret;
	}

	if (head)
		link->last->link = req;
	else
		link->head = req;
	link->last = req;
	return 0;
}

static inline int io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
			 const struct io_uring_sqe *sqe)
	__must_hold(&ctx->uring_lock)
{
	struct io_submit_link *link = &ctx->submit_state.link;
	int ret;

	ret = io_init_req(ctx, req, sqe);
	if (unlikely(ret))
		return io_submit_fail_init(sqe, req, ret);

	trace_io_uring_submit_req(req);

	/*
	 * If we already have a head request, queue this one for async
	 * submittal once the head completes. If we don't have a head but
	 * IOSQE_IO_LINK is set in the sqe, start a new head. This one will be
	 * submitted sync once the chain is complete. If none of those
	 * conditions are true (normal request), then just queue it.
	 */
	if (unlikely(link->head)) {
		ret = io_req_prep_async(req);
		if (unlikely(ret))
			return io_submit_fail_init(sqe, req, ret);

		trace_io_uring_link(req, link->head);
		link->last->link = req;
		link->last = req;

		if (req->flags & IO_REQ_LINK_FLAGS)
			return 0;
		/* last request of the link, flush it */
		req = link->head;
		link->head = NULL;
		if (req->flags & (REQ_F_FORCE_ASYNC | REQ_F_FAIL))
			goto fallback;

	} else if (unlikely(req->flags & (IO_REQ_LINK_FLAGS |
					  REQ_F_FORCE_ASYNC | REQ_F_FAIL))) {
		if (req->flags & IO_REQ_LINK_FLAGS) {
			link->head = req;
			link->last = req;
		} else {
fallback:
			io_queue_sqe_fallback(req);
		}
		return 0;
	}

	io_queue_sqe(req);
	return 0;
}

/*
 * Batched submission is done, ensure local IO is flushed out.
 */
static void io_submit_state_end(struct io_ring_ctx *ctx)
{
	struct io_submit_state *state = &ctx->submit_state;

	if (unlikely(state->link.head))
		io_queue_sqe_fallback(state->link.head);
	/* flush only after queuing links as they can generate completions */
	io_submit_flush_completions(ctx);
	if (state->plug_started)
		blk_finish_plug(&state->plug);
}

/*
 * Start submission side cache.
 */
static void io_submit_state_start(struct io_submit_state *state,
				  unsigned int max_ios)
{
	state->plug_started = false;
	state->need_plug = max_ios > 2;
	state->submit_nr = max_ios;
	/* set only head, no need to init link_last in advance */
	state->link.head = NULL;
}

static void io_commit_sqring(struct io_ring_ctx *ctx)
{
	struct io_rings *rings = ctx->rings;

	/*
	 * Ensure any loads from the SQEs are done at this point,
	 * since once we write the new head, the application could
	 * write new data to them.
	 */
	smp_store_release(&rings->sq.head, ctx->cached_sq_head);
}

/*
 * Fetch an sqe, if one is available. Note this returns a pointer to memory
 * that is mapped by userspace. This means that care needs to be taken to
 * ensure that reads are stable, as we cannot rely on userspace always
 * being a good citizen. If members of the sqe are validated and then later
 * used, it's important that those reads are done through READ_ONCE() to
 * prevent a re-load down the line.
 */
static bool io_get_sqe(struct io_ring_ctx *ctx, const struct io_uring_sqe **sqe)
{
	unsigned mask = ctx->sq_entries - 1;
	unsigned head = ctx->cached_sq_head++ & mask;

	if (!(ctx->flags & IORING_SETUP_NO_SQARRAY)) {
		head = READ_ONCE(ctx->sq_array[head]);
		if (unlikely(head >= ctx->sq_entries)) {
			/* drop invalid entries */
			spin_lock(&ctx->completion_lock);
			ctx->cq_extra--;
			spin_unlock(&ctx->completion_lock);
			WRITE_ONCE(ctx->rings->sq_dropped,
				   READ_ONCE(ctx->rings->sq_dropped) + 1);
			return false;
		}
	}

	/*
	 * The cached sq head (or cq tail) serves two purposes:
	 *
	 * 1) allows us to batch the cost of updating the user visible
	 *    head updates.
	 * 2) allows the kernel side to track the head on its own, even
	 *    though the application is the one updating it.
	 */

	/* double index for 128-byte SQEs, twice as long */
	if (ctx->flags & IORING_SETUP_SQE128)
		head <<= 1;
	*sqe = &ctx->sq_sqes[head];
	return true;
}

int io_submit_sqes(struct io_ring_ctx *ctx, unsigned int nr)
	__must_hold(&ctx->uring_lock)
{
	unsigned int entries = io_sqring_entries(ctx);
	unsigned int left;
	int ret;

	if (unlikely(!entries))
		return 0;
	/* make sure SQ entry isn't read before tail */
	ret = left = min(nr, entries);
	io_get_task_refs(left);
	io_submit_state_start(&ctx->submit_state, left);

	do {
		const struct io_uring_sqe *sqe;
		struct io_kiocb *req;

		if (unlikely(!io_alloc_req(ctx, &req)))
			break;
		if (unlikely(!io_get_sqe(ctx, &sqe))) {
			io_req_add_to_cache(req, ctx);
			break;
		}

		/*
		 * Continue submitting even for sqe failure if the
		 * ring was setup with IORING_SETUP_SUBMIT_ALL
		 */
		if (unlikely(io_submit_sqe(ctx, req, sqe)) &&
		    !(ctx->flags & IORING_SETUP_SUBMIT_ALL)) {
			left--;
			break;
		}
	} while (--left);

	if (unlikely(left)) {
		ret -= left;
		/* try again if it submitted nothing and can't allocate a req */
		if (!ret && io_req_cache_empty(ctx))
			ret = -EAGAIN;
		current->io_uring->cached_refs += left;
	}

	io_submit_state_end(ctx);
	 /* Commit SQ ring head once we've consumed and submitted all SQEs */
	io_commit_sqring(ctx);
	return ret;
}

static int io_wake_function(struct wait_queue_entry *curr, unsigned int mode,
			    int wake_flags, void *key)
{
	struct io_wait_queue *iowq = container_of(curr, struct io_wait_queue, wq);

	/*
	 * Cannot safely flush overflowed CQEs from here, ensure we wake up
	 * the task, and the next invocation will do it.
	 */
	if (io_should_wake(iowq) || io_has_work(iowq->ctx))
		return autoremove_wake_function(curr, mode, wake_flags, key);
	return -1;
}

int io_run_task_work_sig(struct io_ring_ctx *ctx)
{
	if (!llist_empty(&ctx->work_llist)) {
		__set_current_state(TASK_RUNNING);
		if (io_run_local_work(ctx, INT_MAX) > 0)
			return 0;
	}
	if (io_run_task_work() > 0)
		return 0;
	if (task_sigpending(current))
		return -EINTR;
	return 0;
}

static bool current_pending_io(void)
{
	struct io_uring_task *tctx = current->io_uring;

	if (!tctx)
		return false;
	return percpu_counter_read_positive(&tctx->inflight);
}

/* when returns >0, the caller should retry */
static inline int io_cqring_wait_schedule(struct io_ring_ctx *ctx,
					  struct io_wait_queue *iowq)
{
	int ret;

	if (unlikely(READ_ONCE(ctx->check_cq)))
		return 1;
	if (unlikely(!llist_empty(&ctx->work_llist)))
		return 1;
	if (unlikely(test_thread_flag(TIF_NOTIFY_SIGNAL)))
		return 1;
	if (unlikely(task_sigpending(current)))
		return -EINTR;
	if (unlikely(io_should_wake(iowq)))
		return 0;

	/*
	 * Mark us as being in io_wait if we have pending requests, so cpufreq
	 * can take into account that the task is waiting for IO - turns out
	 * to be important for low QD IO.
	 */
	if (current_pending_io())
		current->in_iowait = 1;
	ret = 0;
	if (iowq->timeout == KTIME_MAX)
		schedule();
	else if (!schedule_hrtimeout(&iowq->timeout, HRTIMER_MODE_ABS))
		ret = -ETIME;
	current->in_iowait = 0;
	return ret;
}

/*
 * Wait until events become available, if we don't already have some. The
 * application must reap them itself, as they reside on the shared cq ring.
 */
static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
			  const sigset_t __user *sig, size_t sigsz,
			  struct __kernel_timespec __user *uts)
{
	struct io_wait_queue iowq;
	struct io_rings *rings = ctx->rings;
	int ret;

	if (!io_allowed_run_tw(ctx))
		return -EEXIST;
	if (!llist_empty(&ctx->work_llist))
		io_run_local_work(ctx, min_events);
	io_run_task_work();
	io_cqring_overflow_flush(ctx);
	/* if user messes with these they will just get an early return */
	if (__io_cqring_events_user(ctx) >= min_events)
		return 0;

	init_waitqueue_func_entry(&iowq.wq, io_wake_function);
	iowq.wq.private = current;
	INIT_LIST_HEAD(&iowq.wq.entry);
	iowq.ctx = ctx;
	iowq.nr_timeouts = atomic_read(&ctx->cq_timeouts);
	iowq.cq_tail = READ_ONCE(ctx->rings->cq.head) + min_events;
	iowq.timeout = KTIME_MAX;

	if (uts) {
		struct timespec64 ts;

		if (get_timespec64(&ts, uts))
			return -EFAULT;

		iowq.timeout = ktime_add_ns(timespec64_to_ktime(ts), ktime_get_ns());
		io_napi_adjust_timeout(ctx, &iowq, &ts);
	}

	if (sig) {
#ifdef CONFIG_COMPAT
		if (in_compat_syscall())
			ret = set_compat_user_sigmask((const compat_sigset_t __user *)sig,
						      sigsz);
		else
#endif
			ret = set_user_sigmask(sig, sigsz);

		if (ret)
			return ret;
	}

	io_napi_busy_loop(ctx, &iowq);

	trace_io_uring_cqring_wait(ctx, min_events);
	do {
		int nr_wait = (int) iowq.cq_tail - READ_ONCE(ctx->rings->cq.tail);
		unsigned long check_cq;

		if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
			atomic_set(&ctx->cq_wait_nr, nr_wait);
			set_current_state(TASK_INTERRUPTIBLE);
		} else {
			prepare_to_wait_exclusive(&ctx->cq_wait, &iowq.wq,
							TASK_INTERRUPTIBLE);
		}

		ret = io_cqring_wait_schedule(ctx, &iowq);
		__set_current_state(TASK_RUNNING);
		atomic_set(&ctx->cq_wait_nr, IO_CQ_WAKE_INIT);

		/*
		 * Run task_work after scheduling and before io_should_wake().
		 * If we got woken because of task_work being processed, run it
		 * now rather than let the caller do another wait loop.
		 */
		io_run_task_work();
		if (!llist_empty(&ctx->work_llist))
			io_run_local_work(ctx, nr_wait);

		/*
		 * Non-local task_work will be run on exit to userspace, but
		 * if we're using DEFER_TASKRUN, then we could have waited
		 * with a timeout for a number of requests. If the timeout
		 * hits, we could have some requests ready to process. Ensure
		 * this break is _after_ we have run task_work, to avoid
		 * deferring running potentially pending requests until the
		 * next time we wait for events.
		 */
		if (ret < 0)
			break;

		check_cq = READ_ONCE(ctx->check_cq);
		if (unlikely(check_cq)) {
			/* let the caller flush overflows, retry */
			if (check_cq & BIT(IO_CHECK_CQ_OVERFLOW_BIT))
				io_cqring_do_overflow_flush(ctx);
			if (check_cq & BIT(IO_CHECK_CQ_DROPPED_BIT)) {
				ret = -EBADR;
				break;
			}
		}

		if (io_should_wake(&iowq)) {
			ret = 0;
			break;
		}
		cond_resched();
	} while (1);

	if (!(ctx->flags & IORING_SETUP_DEFER_TASKRUN))
		finish_wait(&ctx->cq_wait, &iowq.wq);
	restore_saved_sigmask_unless(ret == -EINTR);

	return READ_ONCE(rings->cq.head) == READ_ONCE(rings->cq.tail) ? ret : 0;
}

void io_mem_free(void *ptr)
{
	if (!ptr)
		return;

	folio_put(virt_to_folio(ptr));
}

static void io_pages_free(struct page ***pages, int npages)
{
	struct page **page_array = *pages;
	int i;

	if (!page_array)
		return;

	for (i = 0; i < npages; i++)
		unpin_user_page(page_array[i]);
	kvfree(page_array);
	*pages = NULL;
}

static void *__io_uaddr_map(struct page ***pages, unsigned short *npages,
			    unsigned long uaddr, size_t size)
{
	struct page **page_array;
	unsigned int nr_pages;
	void *page_addr;
	int ret, i, pinned;

	*npages = 0;

	if (uaddr & (PAGE_SIZE - 1) || !size)
		return ERR_PTR(-EINVAL);

	nr_pages = (size + PAGE_SIZE - 1) >> PAGE_SHIFT;
	if (nr_pages > USHRT_MAX)
		return ERR_PTR(-EINVAL);
	page_array = kvmalloc_array(nr_pages, sizeof(struct page *), GFP_KERNEL);
	if (!page_array)
		return ERR_PTR(-ENOMEM);


	pinned = pin_user_pages_fast(uaddr, nr_pages, FOLL_WRITE | FOLL_LONGTERM,
				     page_array);
	if (pinned != nr_pages) {
		ret = (pinned < 0) ? pinned : -EFAULT;
		goto free_pages;
	}

	page_addr = page_address(page_array[0]);
	for (i = 0; i < nr_pages; i++) {
		ret = -EINVAL;

		/*
		 * Can't support mapping user allocated ring memory on 32-bit
		 * archs where it could potentially reside in highmem. Just
		 * fail those with -EINVAL, just like we did on kernels that
		 * didn't support this feature.
		 */
		if (PageHighMem(page_array[i]))
			goto free_pages;

		/*
		 * No support for discontig pages for now, should either be a
		 * single normal page, or a huge page. Later on we can add
		 * support for remapping discontig pages, for now we will
		 * just fail them with EINVAL.
		 */
		if (page_address(page_array[i]) != page_addr)
			goto free_pages;
		page_addr += PAGE_SIZE;
	}

	*pages = page_array;
	*npages = nr_pages;
	return page_to_virt(page_array[0]);

free_pages:
	io_pages_free(&page_array, pinned > 0 ? pinned : 0);
	return ERR_PTR(ret);
}

static void *io_rings_map(struct io_ring_ctx *ctx, unsigned long uaddr,
			  size_t size)
{
	return __io_uaddr_map(&ctx->ring_pages, &ctx->n_ring_pages, uaddr,
				size);
}

static void *io_sqes_map(struct io_ring_ctx *ctx, unsigned long uaddr,
			 size_t size)
{
	return __io_uaddr_map(&ctx->sqe_pages, &ctx->n_sqe_pages, uaddr,
				size);
}

static void io_rings_free(struct io_ring_ctx *ctx)
{
	if (!(ctx->flags & IORING_SETUP_NO_MMAP)) {
		io_mem_free(ctx->rings);
		io_mem_free(ctx->sq_sqes);
	} else {
		io_pages_free(&ctx->ring_pages, ctx->n_ring_pages);
		ctx->n_ring_pages = 0;
		io_pages_free(&ctx->sqe_pages, ctx->n_sqe_pages);
		ctx->n_sqe_pages = 0;
	}

	ctx->rings = NULL;
	ctx->sq_sqes = NULL;
}

void *io_mem_alloc(size_t size)
{
	gfp_t gfp = GFP_KERNEL_ACCOUNT | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP;
	void *ret;

	ret = (void *) __get_free_pages(gfp, get_order(size));
	if (ret)
		return ret;
	return ERR_PTR(-ENOMEM);
}

static unsigned long rings_size(struct io_ring_ctx *ctx, unsigned int sq_entries,
				unsigned int cq_entries, size_t *sq_offset)
{
	struct io_rings *rings;
	size_t off, sq_array_size;

	off = struct_size(rings, cqes, cq_entries);
	if (off == SIZE_MAX)
		return SIZE_MAX;
	if (ctx->flags & IORING_SETUP_CQE32) {
		if (check_shl_overflow(off, 1, &off))
			return SIZE_MAX;
	}

#ifdef CONFIG_SMP
	off = ALIGN(off, SMP_CACHE_BYTES);
	if (off == 0)
		return SIZE_MAX;
#endif

	if (ctx->flags & IORING_SETUP_NO_SQARRAY) {
		if (sq_offset)
			*sq_offset = SIZE_MAX;
		return off;
	}

	if (sq_offset)
		*sq_offset = off;

	sq_array_size = array_size(sizeof(u32), sq_entries);
	if (sq_array_size == SIZE_MAX)
		return SIZE_MAX;

	if (check_add_overflow(off, sq_array_size, &off))
		return SIZE_MAX;

	return off;
}

static void io_req_caches_free(struct io_ring_ctx *ctx)
{
	struct io_kiocb *req;
	int nr = 0;

	mutex_lock(&ctx->uring_lock);
	io_flush_cached_locked_reqs(ctx, &ctx->submit_state);

	while (!io_req_cache_empty(ctx)) {
		req = io_extract_req(ctx);
		kmem_cache_free(req_cachep, req);
		nr++;
	}
	if (nr)
		percpu_ref_put_many(&ctx->refs, nr);
	mutex_unlock(&ctx->uring_lock);
}

static void io_rsrc_node_cache_free(struct io_cache_entry *entry)
{
	kfree(container_of(entry, struct io_rsrc_node, cache));
}

static __cold void io_ring_ctx_free(struct io_ring_ctx *ctx)
{
	io_sq_thread_finish(ctx);
	/* __io_rsrc_put_work() may need uring_lock to progress, wait w/o it */
	if (WARN_ON_ONCE(!list_empty(&ctx->rsrc_ref_list)))
		return;

	mutex_lock(&ctx->uring_lock);
	if (ctx->buf_data)
		__io_sqe_buffers_unregister(ctx);
	if (ctx->file_data)
		__io_sqe_files_unregister(ctx);
	io_cqring_overflow_kill(ctx);
	io_eventfd_unregister(ctx);
	io_alloc_cache_free(&ctx->apoll_cache, io_apoll_cache_free);
	io_alloc_cache_free(&ctx->netmsg_cache, io_netmsg_cache_free);
	io_futex_cache_free(ctx);
	io_destroy_buffers(ctx);
	mutex_unlock(&ctx->uring_lock);
	if (ctx->sq_creds)
		put_cred(ctx->sq_creds);
	if (ctx->submitter_task)
		put_task_struct(ctx->submitter_task);

	/* there are no registered resources left, nobody uses it */
	if (ctx->rsrc_node)
		io_rsrc_node_destroy(ctx, ctx->rsrc_node);

	WARN_ON_ONCE(!list_empty(&ctx->rsrc_ref_list));
	WARN_ON_ONCE(!list_empty(&ctx->ltimeout_list));

	io_alloc_cache_free(&ctx->rsrc_node_cache, io_rsrc_node_cache_free);
	if (ctx->mm_account) {
		mmdrop(ctx->mm_account);
		ctx->mm_account = NULL;
	}
	io_rings_free(ctx);
	io_kbuf_mmap_list_free(ctx);

	percpu_ref_exit(&ctx->refs);
	free_uid(ctx->user);
	io_req_caches_free(ctx);
	if (ctx->hash_map)
		io_wq_put_hash(ctx->hash_map);
	io_napi_free(ctx);
	kfree(ctx->cancel_table.hbs);
	kfree(ctx->cancel_table_locked.hbs);
	xa_destroy(&ctx->io_bl_xa);
	kfree(ctx);
}

static __cold void io_activate_pollwq_cb(struct callback_head *cb)
{
	struct io_ring_ctx *ctx = container_of(cb, struct io_ring_ctx,
					       poll_wq_task_work);

	mutex_lock(&ctx->uring_lock);
	ctx->poll_activated = true;
	mutex_unlock(&ctx->uring_lock);

	/*
	 * Wake ups for some events between start of polling and activation
	 * might've been lost due to loose synchronisation.
	 */
	wake_up_all(&ctx->poll_wq);
	percpu_ref_put(&ctx->refs);
}

__cold void io_activate_pollwq(struct io_ring_ctx *ctx)
{
	spin_lock(&ctx->completion_lock);
	/* already activated or in progress */
	if (ctx->poll_activated || ctx->poll_wq_task_work.func)
		goto out;
	if (WARN_ON_ONCE(!ctx->task_complete))
		goto out;
	if (!ctx->submitter_task)
		goto out;
	/*
	 * with ->submitter_task only the submitter task completes requests, we
	 * only need to sync with it, which is done by injecting a tw
	 */
	init_task_work(&ctx->poll_wq_task_work, io_activate_pollwq_cb);
	percpu_ref_get(&ctx->refs);
	if (task_work_add(ctx->submitter_task, &ctx->poll_wq_task_work, TWA_SIGNAL))
		percpu_ref_put(&ctx->refs);
out:
	spin_unlock(&ctx->completion_lock);
}

static __poll_t io_uring_poll(struct file *file, poll_table *wait)
{
	struct io_ring_ctx *ctx = file->private_data;
	__poll_t mask = 0;

	if (unlikely(!ctx->poll_activated))
		io_activate_pollwq(ctx);

	poll_wait(file, &ctx->poll_wq, wait);
	/*
	 * synchronizes with barrier from wq_has_sleeper call in
	 * io_commit_cqring
	 */
	smp_rmb();
	if (!io_sqring_full(ctx))
		mask |= EPOLLOUT | EPOLLWRNORM;

	/*
	 * Don't flush cqring overflow list here, just do a simple check.
	 * Otherwise there could possible be ABBA deadlock:
	 *      CPU0                    CPU1
	 *      ----                    ----
	 * lock(&ctx->uring_lock);
	 *                              lock(&ep->mtx);
	 *                              lock(&ctx->uring_lock);
	 * lock(&ep->mtx);
	 *
	 * Users may get EPOLLIN meanwhile seeing nothing in cqring, this
	 * pushes them to do the flush.
	 */

	if (__io_cqring_events_user(ctx) || io_has_work(ctx))
		mask |= EPOLLIN | EPOLLRDNORM;

	return mask;
}

struct io_tctx_exit {
	struct callback_head		task_work;
	struct completion		completion;
	struct io_ring_ctx		*ctx;
};

static __cold void io_tctx_exit_cb(struct callback_head *cb)
{
	struct io_uring_task *tctx = current->io_uring;
	struct io_tctx_exit *work;

	work = container_of(cb, struct io_tctx_exit, task_work);
	/*
	 * When @in_cancel, we're in cancellation and it's racy to remove the
	 * node. It'll be removed by the end of cancellation, just ignore it.
	 * tctx can be NULL if the queueing of this task_work raced with
	 * work cancelation off the exec path.
	 */
	if (tctx && !atomic_read(&tctx->in_cancel))
		io_uring_del_tctx_node((unsigned long)work->ctx);
	complete(&work->completion);
}

static __cold bool io_cancel_ctx_cb(struct io_wq_work *work, void *data)
{
	struct io_kiocb *req = container_of(work, struct io_kiocb, work);

	return req->ctx == data;
}

static __cold void io_ring_exit_work(struct work_struct *work)
{
	struct io_ring_ctx *ctx = container_of(work, struct io_ring_ctx, exit_work);
	unsigned long timeout = jiffies + HZ * 60 * 5;
	unsigned long interval = HZ / 20;
	struct io_tctx_exit exit;
	struct io_tctx_node *node;
	int ret;

	/*
	 * If we're doing polled IO and end up having requests being
	 * submitted async (out-of-line), then completions can come in while
	 * we're waiting for refs to drop. We need to reap these manually,
	 * as nobody else will be looking for them.
	 */
	do {
		if (test_bit(IO_CHECK_CQ_OVERFLOW_BIT, &ctx->check_cq)) {
			mutex_lock(&ctx->uring_lock);
			io_cqring_overflow_kill(ctx);
			mutex_unlock(&ctx->uring_lock);
		}

		if (ctx->flags & IORING_SETUP_DEFER_TASKRUN)
			io_move_task_work_from_local(ctx);

		while (io_uring_try_cancel_requests(ctx, NULL, true))
			cond_resched();

		if (ctx->sq_data) {
			struct io_sq_data *sqd = ctx->sq_data;
			struct task_struct *tsk;

			io_sq_thread_park(sqd);
			tsk = sqd->thread;
			if (tsk && tsk->io_uring && tsk->io_uring->io_wq)
				io_wq_cancel_cb(tsk->io_uring->io_wq,
						io_cancel_ctx_cb, ctx, true);
			io_sq_thread_unpark(sqd);
		}

		io_req_caches_free(ctx);

		if (WARN_ON_ONCE(time_after(jiffies, timeout))) {
			/* there is little hope left, don't run it too often */
			interval = HZ * 60;
		}
		/*
		 * This is really an uninterruptible wait, as it has to be
		 * complete. But it's also run from a kworker, which doesn't
		 * take signals, so it's fine to make it interruptible. This
		 * avoids scenarios where we knowingly can wait much longer
		 * on completions, for example if someone does a SIGSTOP on
		 * a task that needs to finish task_work to make this loop
		 * complete. That's a synthetic situation that should not
		 * cause a stuck task backtrace, and hence a potential panic
		 * on stuck tasks if that is enabled.
		 */
	} while (!wait_for_completion_interruptible_timeout(&ctx->ref_comp, interval));

	init_completion(&exit.completion);
	init_task_work(&exit.task_work, io_tctx_exit_cb);
	exit.ctx = ctx;

	mutex_lock(&ctx->uring_lock);
	while (!list_empty(&ctx->tctx_list)) {
		WARN_ON_ONCE(time_after(jiffies, timeout));

		node = list_first_entry(&ctx->tctx_list, struct io_tctx_node,
					ctx_node);
		/* don't spin on a single task if cancellation failed */
		list_rotate_left(&ctx->tctx_list);
		ret = task_work_add(node->task, &exit.task_work, TWA_SIGNAL);
		if (WARN_ON_ONCE(ret))
			continue;

		mutex_unlock(&ctx->uring_lock);
		/*
		 * See comment above for
		 * wait_for_completion_interruptible_timeout() on why this
		 * wait is marked as interruptible.
		 */
		wait_for_completion_interruptible(&exit.completion);
		mutex_lock(&ctx->uring_lock);
	}
	mutex_unlock(&ctx->uring_lock);
	spin_lock(&ctx->completion_lock);
	spin_unlock(&ctx->completion_lock);

	/* pairs with RCU read section in io_req_local_work_add() */
	if (ctx->flags & IORING_SETUP_DEFER_TASKRUN)
		synchronize_rcu();

	io_ring_ctx_free(ctx);
}

static __cold void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
{
	unsigned long index;
	struct creds *creds;

	mutex_lock(&ctx->uring_lock);
	percpu_ref_kill(&ctx->refs);
	xa_for_each(&ctx->personalities, index, creds)
		io_unregister_personality(ctx, index);
	if (ctx->rings)
		io_poll_remove_all(ctx, NULL, true);
	mutex_unlock(&ctx->uring_lock);

	/*
	 * If we failed setting up the ctx, we might not have any rings
	 * and therefore did not submit any requests
	 */
	if (ctx->rings)
		io_kill_timeouts(ctx, NULL, true);

	flush_delayed_work(&ctx->fallback_work);

	INIT_WORK(&ctx->exit_work, io_ring_exit_work);
	/*
	 * Use system_unbound_wq to avoid spawning tons of event kworkers
	 * if we're exiting a ton of rings at the same time. It just adds
	 * noise and overhead, there's no discernable change in runtime
	 * over using system_wq.
	 */
	queue_work(iou_wq, &ctx->exit_work);
}

static int io_uring_release(struct inode *inode, struct file *file)
{
	struct io_ring_ctx *ctx = file->private_data;

	file->private_data = NULL;
	io_ring_ctx_wait_and_kill(ctx);
	return 0;
}

struct io_task_cancel {
	struct task_struct *task;
	bool all;
};

static bool io_cancel_task_cb(struct io_wq_work *work, void *data)
{
	struct io_kiocb *req = container_of(work, struct io_kiocb, work);
	struct io_task_cancel *cancel = data;

	return io_match_task_safe(req, cancel->task, cancel->all);
}

static __cold bool io_cancel_defer_files(struct io_ring_ctx *ctx,
					 struct task_struct *task,
					 bool cancel_all)
{
	struct io_defer_entry *de;
	LIST_HEAD(list);

	spin_lock(&ctx->completion_lock);
	list_for_each_entry_reverse(de, &ctx->defer_list, list) {
		if (io_match_task_safe(de->req, task, cancel_all)) {
			list_cut_position(&list, &ctx->defer_list, &de->list);
			break;
		}
	}
	spin_unlock(&ctx->completion_lock);
	if (list_empty(&list))
		return false;

	while (!list_empty(&list)) {
		de = list_first_entry(&list, struct io_defer_entry, list);
		list_del_init(&de->list);
		io_req_task_queue_fail(de->req, -ECANCELED);
		kfree(de);
	}
	return true;
}

static __cold bool io_uring_try_cancel_iowq(struct io_ring_ctx *ctx)
{
	struct io_tctx_node *node;
	enum io_wq_cancel cret;
	bool ret = false;

	mutex_lock(&ctx->uring_lock);
	list_for_each_entry(node, &ctx->tctx_list, ctx_node) {
		struct io_uring_task *tctx = node->task->io_uring;

		/*
		 * io_wq will stay alive while we hold uring_lock, because it's
		 * killed after ctx nodes, which requires to take the lock.
		 */
		if (!tctx || !tctx->io_wq)
			continue;
		cret = io_wq_cancel_cb(tctx->io_wq, io_cancel_ctx_cb, ctx, true);
		ret |= (cret != IO_WQ_CANCEL_NOTFOUND);
	}
	mutex_unlock(&ctx->uring_lock);

	return ret;
}

static bool io_uring_try_cancel_uring_cmd(struct io_ring_ctx *ctx,
		struct task_struct *task, bool cancel_all)
{
	struct hlist_node *tmp;
	struct io_kiocb *req;
	bool ret = false;

	lockdep_assert_held(&ctx->uring_lock);

	hlist_for_each_entry_safe(req, tmp, &ctx->cancelable_uring_cmd,
			hash_node) {
		struct io_uring_cmd *cmd = io_kiocb_to_cmd(req,
				struct io_uring_cmd);
		struct file *file = req->file;

		if (!cancel_all && req->task != task)
			continue;

		if (cmd->flags & IORING_URING_CMD_CANCELABLE) {
			/* ->sqe isn't available if no async data */
			if (!req_has_async_data(req))
				cmd->sqe = NULL;
			file->f_op->uring_cmd(cmd, IO_URING_F_CANCEL);
			ret = true;
		}
	}
	io_submit_flush_completions(ctx);

	return ret;
}

static __cold bool io_uring_try_cancel_requests(struct io_ring_ctx *ctx,
						struct task_struct *task,
						bool cancel_all)
{
	struct io_task_cancel cancel = { .task = task, .all = cancel_all, };
	struct io_uring_task *tctx = task ? task->io_uring : NULL;
	enum io_wq_cancel cret;
	bool ret = false;

	/* set it so io_req_local_work_add() would wake us up */
	if (ctx->flags & IORING_SETUP_DEFER_TASKRUN) {
		atomic_set(&ctx->cq_wait_nr, 1);
		smp_mb();
	}

	/* failed during ring init, it couldn't have issued any requests */
	if (!ctx->rings)
		return false;

	if (!task) {
		ret |= io_uring_try_cancel_iowq(ctx);
	} else if (tctx && tctx->io_wq) {
		/*
		 * Cancels requests of all rings, not only @ctx, but
		 * it's fine as the task is in exit/exec.
		 */
		cret = io_wq_cancel_cb(tctx->io_wq, io_cancel_task_cb,
				       &cancel, true);
		ret |= (cret != IO_WQ_CANCEL_NOTFOUND);
	}

	/* SQPOLL thread does its own polling */
	if ((!(ctx->flags & IORING_SETUP_SQPOLL) && cancel_all) ||
	    (ctx->sq_data && ctx->sq_data->thread == current)) {
		while (!wq_list_empty(&ctx->iopoll_list)) {
			io_iopoll_try_reap_events(ctx);
			ret = true;
			cond_resched();
		}
	}

	if ((ctx->flags & IORING_SETUP_DEFER_TASKRUN) &&
	    io_allowed_defer_tw_run(ctx))
		ret |= io_run_local_work(ctx, INT_MAX) > 0;
	ret |= io_cancel_defer_files(ctx, task, cancel_all);
	mutex_lock(&ctx->uring_lock);
	ret |= io_poll_remove_all(ctx, task, cancel_all);
	ret |= io_waitid_remove_all(ctx, task, cancel_all);
	ret |= io_futex_remove_all(ctx, task, cancel_all);
	ret |= io_uring_try_cancel_uring_cmd(ctx, task, cancel_all);
	mutex_unlock(&ctx->uring_lock);
	ret |= io_kill_timeouts(ctx, task, cancel_all);
	if (task)
		ret |= io_run_task_work() > 0;
	return ret;
}

static s64 tctx_inflight(struct io_uring_task *tctx, bool tracked)
{
	if (tracked)
		return atomic_read(&tctx->inflight_tracked);
	return percpu_counter_sum(&tctx->inflight);
}

/*
 * Find any io_uring ctx that this task has registered or done IO on, and cancel
 * requests. @sqd should be not-null IFF it's an SQPOLL thread cancellation.
 */
__cold void io_uring_cancel_generic(bool cancel_all, struct io_sq_data *sqd)
{
	struct io_uring_task *tctx = current->io_uring;
	struct io_ring_ctx *ctx;
	struct io_tctx_node *node;
	unsigned long index;
	s64 inflight;
	DEFINE_WAIT(wait);

	WARN_ON_ONCE(sqd && sqd->thread != current);

	if (!current->io_uring)
		return;
	if (tctx->io_wq)
		io_wq_exit_start(tctx->io_wq);

	atomic_inc(&tctx->in_cancel);
	do {
		bool loop = false;

		io_uring_drop_tctx_refs(current);
		/* read completions before cancelations */
		inflight = tctx_inflight(tctx, !cancel_all);
		if (!inflight)
			break;

		if (!sqd) {
			xa_for_each(&tctx->xa, index, node) {
				/* sqpoll task will cancel all its requests */
				if (node->ctx->sq_data)
					continue;
				loop |= io_uring_try_cancel_requests(node->ctx,
							current, cancel_all);
			}
		} else {
			list_for_each_entry(ctx, &sqd->ctx_list, sqd_list)
				loop |= io_uring_try_cancel_requests(ctx,
								     current,
								     cancel_all);
		}

		if (loop) {
			cond_resched();
			continue;
		}

		prepare_to_wait(&tctx->wait, &wait, TASK_INTERRUPTIBLE);
		io_run_task_work();
		io_uring_drop_tctx_refs(current);
		xa_for_each(&tctx->xa, index, node) {
			if (!llist_empty(&node->ctx->work_llist)) {
				WARN_ON_ONCE(node->ctx->submitter_task &&
					     node->ctx->submitter_task != current);
				goto end_wait;
			}
		}
		/*
		 * If we've seen completions, retry without waiting. This
		 * avoids a race where a completion comes in before we did
		 * prepare_to_wait().
		 */
		if (inflight == tctx_inflight(tctx, !cancel_all))
			schedule();
end_wait:
		finish_wait(&tctx->wait, &wait);
	} while (1);

	io_uring_clean_tctx(tctx);
	if (cancel_all) {
		/*
		 * We shouldn't run task_works after cancel, so just leave
		 * ->in_cancel set for normal exit.
		 */
		atomic_dec(&tctx->in_cancel);
		/* for exec all current's requests should be gone, kill tctx */
		__io_uring_free(current);
	}
}

void __io_uring_cancel(bool cancel_all)
{
	io_uring_cancel_generic(cancel_all, NULL);
}

static void *io_uring_validate_mmap_request(struct file *file,
					    loff_t pgoff, size_t sz)
{
	struct io_ring_ctx *ctx = file->private_data;
	loff_t offset = pgoff << PAGE_SHIFT;
	struct page *page;
	void *ptr;

	switch (offset & IORING_OFF_MMAP_MASK) {
	case IORING_OFF_SQ_RING:
	case IORING_OFF_CQ_RING:
		/* Don't allow mmap if the ring was setup without it */
		if (ctx->flags & IORING_SETUP_NO_MMAP)
			return ERR_PTR(-EINVAL);
		ptr = ctx->rings;
		break;
	case IORING_OFF_SQES:
		/* Don't allow mmap if the ring was setup without it */
		if (ctx->flags & IORING_SETUP_NO_MMAP)
			return ERR_PTR(-EINVAL);
		ptr = ctx->sq_sqes;
		break;
	case IORING_OFF_PBUF_RING: {
		struct io_buffer_list *bl;
		unsigned int bgid;

		bgid = (offset & ~IORING_OFF_MMAP_MASK) >> IORING_OFF_PBUF_SHIFT;
		bl = io_pbuf_get_bl(ctx, bgid);
		if (IS_ERR(bl))
			return bl;
		ptr = bl->buf_ring;
		io_put_bl(ctx, bl);
		break;
		}
	default:
		return ERR_PTR(-EINVAL);
	}

	page = virt_to_head_page(ptr);
	if (sz > page_size(page))
		return ERR_PTR(-EINVAL);

	return ptr;
}

#ifdef CONFIG_MMU

static __cold int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
{
	size_t sz = vma->vm_end - vma->vm_start;
	unsigned long pfn;
	void *ptr;

	ptr = io_uring_validate_mmap_request(file, vma->vm_pgoff, sz);
	if (IS_ERR(ptr))
		return PTR_ERR(ptr);

	pfn = virt_to_phys(ptr) >> PAGE_SHIFT;
	return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot);
}

static unsigned long io_uring_mmu_get_unmapped_area(struct file *filp,
			unsigned long addr, unsigned long len,
			unsigned long pgoff, unsigned long flags)
{
	void *ptr;

	/*
	 * Do not allow to map to user-provided address to avoid breaking the
	 * aliasing rules. Userspace is not able to guess the offset address of
	 * kernel kmalloc()ed memory area.
	 */
	if (addr)
		return -EINVAL;

	ptr = io_uring_validate_mmap_request(filp, pgoff, len);
	if (IS_ERR(ptr))
		return -ENOMEM;

	/*
	 * Some architectures have strong cache aliasing requirements.
	 * For such architectures we need a coherent mapping which aliases
	 * kernel memory *and* userspace memory. To achieve that:
	 * - use a NULL file pointer to reference physical memory, and
	 * - use the kernel virtual address of the shared io_uring context
	 *   (instead of the userspace-provided address, which has to be 0UL
	 *   anyway).
	 * - use the same pgoff which the get_unmapped_area() uses to
	 *   calculate the page colouring.
	 * For architectures without such aliasing requirements, the
	 * architecture will return any suitable mapping because addr is 0.
	 */
	filp = NULL;
	flags |= MAP_SHARED;
	pgoff = 0;	/* has been translated to ptr above */
#ifdef SHM_COLOUR
	addr = (uintptr_t) ptr;
	pgoff = addr >> PAGE_SHIFT;
#else
	addr = 0UL;
#endif
	return current->mm->get_unmapped_area(filp, addr, len, pgoff, flags);
}

#else /* !CONFIG_MMU */

static int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
{
	return is_nommu_shared_mapping(vma->vm_flags) ? 0 : -EINVAL;
}

static unsigned int io_uring_nommu_mmap_capabilities(struct file *file)
{
	return NOMMU_MAP_DIRECT | NOMMU_MAP_READ | NOMMU_MAP_WRITE;
}

static unsigned long io_uring_nommu_get_unmapped_area(struct file *file,
	unsigned long addr, unsigned long len,
	unsigned long pgoff, unsigned long flags)
{
	void *ptr;

	ptr = io_uring_validate_mmap_request(file, pgoff, len);
	if (IS_ERR(ptr))
		return PTR_ERR(ptr);

	return (unsigned long) ptr;
}

#endif /* !CONFIG_MMU */

static int io_validate_ext_arg(unsigned flags, const void __user *argp, size_t argsz)
{
	if (flags & IORING_ENTER_EXT_ARG) {
		struct io_uring_getevents_arg arg;

		if (argsz != sizeof(arg))
			return -EINVAL;
		if (copy_from_user(&arg, argp, sizeof(arg)))
			return -EFAULT;
	}
	return 0;
}

static int io_get_ext_arg(unsigned flags, const void __user *argp, size_t *argsz,
			  struct __kernel_timespec __user **ts,
			  const sigset_t __user **sig)
{
	struct io_uring_getevents_arg arg;

	/*
	 * If EXT_ARG isn't set, then we have no timespec and the argp pointer
	 * is just a pointer to the sigset_t.
	 */
	if (!(flags & IORING_ENTER_EXT_ARG)) {
		*sig = (const sigset_t __user *) argp;
		*ts = NULL;
		return 0;
	}

	/*
	 * EXT_ARG is set - ensure we agree on the size of it and copy in our
	 * timespec and sigset_t pointers if good.
	 */
	if (*argsz != sizeof(arg))
		return -EINVAL;
	if (copy_from_user(&arg, argp, sizeof(arg)))
		return -EFAULT;
	if (arg.pad)
		return -EINVAL;
	*sig = u64_to_user_ptr(arg.sigmask);
	*argsz = arg.sigmask_sz;
	*ts = u64_to_user_ptr(arg.ts);
	return 0;
}

SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
		u32, min_complete, u32, flags, const void __user *, argp,
		size_t, argsz)
{
	struct io_ring_ctx *ctx;
	struct file *file;
	long ret;

	if (unlikely(flags & ~(IORING_ENTER_GETEVENTS | IORING_ENTER_SQ_WAKEUP |
			       IORING_ENTER_SQ_WAIT | IORING_ENTER_EXT_ARG |
			       IORING_ENTER_REGISTERED_RING)))
		return -EINVAL;

	/*
	 * Ring fd has been registered via IORING_REGISTER_RING_FDS, we
	 * need only dereference our task private array to find it.
	 */
	if (flags & IORING_ENTER_REGISTERED_RING) {
		struct io_uring_task *tctx = current->io_uring;

		if (unlikely(!tctx || fd >= IO_RINGFD_REG_MAX))
			return -EINVAL;
		fd = array_index_nospec(fd, IO_RINGFD_REG_MAX);
		file = tctx->registered_rings[fd];
		if (unlikely(!file))
			return -EBADF;
	} else {
		file = fget(fd);
		if (unlikely(!file))
			return -EBADF;
		ret = -EOPNOTSUPP;
		if (unlikely(!io_is_uring_fops(file)))
			goto out;
	}

	ctx = file->private_data;
	ret = -EBADFD;
	if (unlikely(ctx->flags & IORING_SETUP_R_DISABLED))
		goto out;

	/*
	 * For SQ polling, the thread will do all submissions and completions.
	 * Just return the requested submit count, and wake the thread if
	 * we were asked to.
	 */
	ret = 0;
	if (ctx->flags & IORING_SETUP_SQPOLL) {
		io_cqring_overflow_flush(ctx);

		if (unlikely(ctx->sq_data->thread == NULL)) {
			ret = -EOWNERDEAD;
			goto out;
		}
		if (flags & IORING_ENTER_SQ_WAKEUP)
			wake_up(&ctx->sq_data->wait);
		if (flags & IORING_ENTER_SQ_WAIT)
			io_sqpoll_wait_sq(ctx);

		ret = to_submit;
	} else if (to_submit) {
		ret = io_uring_add_tctx_node(ctx);
		if (unlikely(ret))
			goto out;

		mutex_lock(&ctx->uring_lock);
		ret = io_submit_sqes(ctx, to_submit);
		if (ret != to_submit) {
			mutex_unlock(&ctx->uring_lock);
			goto out;
		}
		if (flags & IORING_ENTER_GETEVENTS) {
			if (ctx->syscall_iopoll)
				goto iopoll_locked;
			/*
			 * Ignore errors, we'll soon call io_cqring_wait() and
			 * it should handle ownership problems if any.
			 */
			if (ctx->flags & IORING_SETUP_DEFER_TASKRUN)
				(void)io_run_local_work_locked(ctx, min_complete);
		}
		mutex_unlock(&ctx->uring_lock);
	}

	if (flags & IORING_ENTER_GETEVENTS) {
		int ret2;

		if (ctx->syscall_iopoll) {
			/*
			 * We disallow the app entering submit/complete with
			 * polling, but we still need to lock the ring to
			 * prevent racing with polled issue that got punted to
			 * a workqueue.
			 */
			mutex_lock(&ctx->uring_lock);
iopoll_locked:
			ret2 = io_validate_ext_arg(flags, argp, argsz);
			if (likely(!ret2)) {
				min_complete = min(min_complete,
						   ctx->cq_entries);
				ret2 = io_iopoll_check(ctx, min_complete);
			}
			mutex_unlock(&ctx->uring_lock);
		} else {
			const sigset_t __user *sig;
			struct __kernel_timespec __user *ts;

			ret2 = io_get_ext_arg(flags, argp, &argsz, &ts, &sig);
			if (likely(!ret2)) {
				min_complete = min(min_complete,
						   ctx->cq_entries);
				ret2 = io_cqring_wait(ctx, min_complete, sig,
						      argsz, ts);
			}
		}

		if (!ret) {
			ret = ret2;

			/*
			 * EBADR indicates that one or more CQE were dropped.
			 * Once the user has been informed we can clear the bit
			 * as they are obviously ok with those drops.
			 */
			if (unlikely(ret2 == -EBADR))
				clear_bit(IO_CHECK_CQ_DROPPED_BIT,
					  &ctx->check_cq);
		}
	}
out:
	if (!(flags & IORING_ENTER_REGISTERED_RING))
		fput(file);
	return ret;
}

static const struct file_operations io_uring_fops = {
	.release	= io_uring_release,
	.mmap		= io_uring_mmap,
#ifndef CONFIG_MMU
	.get_unmapped_area = io_uring_nommu_get_unmapped_area,
	.mmap_capabilities = io_uring_nommu_mmap_capabilities,
#else
	.get_unmapped_area = io_uring_mmu_get_unmapped_area,
#endif
	.poll		= io_uring_poll,
#ifdef CONFIG_PROC_FS
	.show_fdinfo	= io_uring_show_fdinfo,
#endif
};

bool io_is_uring_fops(struct file *file)
{
	return file->f_op == &io_uring_fops;
}

static __cold int io_allocate_scq_urings(struct io_ring_ctx *ctx,
					 struct io_uring_params *p)
{
	struct io_rings *rings;
	size_t size, sq_array_offset;
	void *ptr;

	/* make sure these are sane, as we already accounted them */
	ctx->sq_entries = p->sq_entries;
	ctx->cq_entries = p->cq_entries;

	size = rings_size(ctx, p->sq_entries, p->cq_entries, &sq_array_offset);
	if (size == SIZE_MAX)
		return -EOVERFLOW;

	if (!(ctx->flags & IORING_SETUP_NO_MMAP))
		rings = io_mem_alloc(size);
	else
		rings = io_rings_map(ctx, p->cq_off.user_addr, size);

	if (IS_ERR(rings))
		return PTR_ERR(rings);

	ctx->rings = rings;
	if (!(ctx->flags & IORING_SETUP_NO_SQARRAY))
		ctx->sq_array = (u32 *)((char *)rings + sq_array_offset);
	rings->sq_ring_mask = p->sq_entries - 1;
	rings->cq_ring_mask = p->cq_entries - 1;
	rings->sq_ring_entries = p->sq_entries;
	rings->cq_ring_entries = p->cq_entries;

	if (p->flags & IORING_SETUP_SQE128)
		size = array_size(2 * sizeof(struct io_uring_sqe), p->sq_entries);
	else
		size = array_size(sizeof(struct io_uring_sqe), p->sq_entries);
	if (size == SIZE_MAX) {
		io_rings_free(ctx);
		return -EOVERFLOW;
	}

	if (!(ctx->flags & IORING_SETUP_NO_MMAP))
		ptr = io_mem_alloc(size);
	else
		ptr = io_sqes_map(ctx, p->sq_off.user_addr, size);

	if (IS_ERR(ptr)) {
		io_rings_free(ctx);
		return PTR_ERR(ptr);
	}

	ctx->sq_sqes = ptr;
	return 0;
}

static int io_uring_install_fd(struct file *file)
{
	int fd;

	fd = get_unused_fd_flags(O_RDWR | O_CLOEXEC);
	if (fd < 0)
		return fd;
	fd_install(fd, file);
	return fd;
}

/*
 * Allocate an anonymous fd, this is what constitutes the application
 * visible backing of an io_uring instance. The application mmaps this
 * fd to gain access to the SQ/CQ ring details.
 */
static struct file *io_uring_get_file(struct io_ring_ctx *ctx)
{
	/* Create a new inode so that the LSM can block the creation.  */
	return anon_inode_create_getfile("[io_uring]", &io_uring_fops, ctx,
					 O_RDWR | O_CLOEXEC, NULL);
}

static __cold int io_uring_create(unsigned entries, struct io_uring_params *p,
				  struct io_uring_params __user *params)
{
	struct io_ring_ctx *ctx;
	struct io_uring_task *tctx;
	struct file *file;
	int ret;

	if (!entries)
		return -EINVAL;
	if (entries > IORING_MAX_ENTRIES) {
		if (!(p->flags & IORING_SETUP_CLAMP))
			return -EINVAL;
		entries = IORING_MAX_ENTRIES;
	}

	if ((p->flags & IORING_SETUP_REGISTERED_FD_ONLY)
	    && !(p->flags & IORING_SETUP_NO_MMAP))
		return -EINVAL;

	/*
	 * Use twice as many entries for the CQ ring. It's possible for the
	 * application to drive a higher depth than the size of the SQ ring,
	 * since the sqes are only used at submission time. This allows for
	 * some flexibility in overcommitting a bit. If the application has
	 * set IORING_SETUP_CQSIZE, it will have passed in the desired number
	 * of CQ ring entries manually.
	 */
	p->sq_entries = roundup_pow_of_two(entries);
	if (p->flags & IORING_SETUP_CQSIZE) {
		/*
		 * If IORING_SETUP_CQSIZE is set, we do the same roundup
		 * to a power-of-two, if it isn't already. We do NOT impose
		 * any cq vs sq ring sizing.
		 */
		if (!p->cq_entries)
			return -EINVAL;
		if (p->cq_entries > IORING_MAX_CQ_ENTRIES) {
			if (!(p->flags & IORING_SETUP_CLAMP))
				return -EINVAL;
			p->cq_entries = IORING_MAX_CQ_ENTRIES;
		}
		p->cq_entries = roundup_pow_of_two(p->cq_entries);
		if (p->cq_entries < p->sq_entries)
			return -EINVAL;
	} else {
		p->cq_entries = 2 * p->sq_entries;
	}

	ctx = io_ring_ctx_alloc(p);
	if (!ctx)
		return -ENOMEM;

	if ((ctx->flags & IORING_SETUP_DEFER_TASKRUN) &&
	    !(ctx->flags & IORING_SETUP_IOPOLL) &&
	    !(ctx->flags & IORING_SETUP_SQPOLL))
		ctx->task_complete = true;

	if (ctx->task_complete || (ctx->flags & IORING_SETUP_IOPOLL))
		ctx->lockless_cq = true;

	/*
	 * lazy poll_wq activation relies on ->task_complete for synchronisation
	 * purposes, see io_activate_pollwq()
	 */
	if (!ctx->task_complete)
		ctx->poll_activated = true;

	/*
	 * When SETUP_IOPOLL and SETUP_SQPOLL are both enabled, user
	 * space applications don't need to do io completion events
	 * polling again, they can rely on io_sq_thread to do polling
	 * work, which can reduce cpu usage and uring_lock contention.
	 */
	if (ctx->flags & IORING_SETUP_IOPOLL &&
	    !(ctx->flags & IORING_SETUP_SQPOLL))
		ctx->syscall_iopoll = 1;

	ctx->compat = in_compat_syscall();
	if (!ns_capable_noaudit(&init_user_ns, CAP_IPC_LOCK))
		ctx->user = get_uid(current_user());

	/*
	 * For SQPOLL, we just need a wakeup, always. For !SQPOLL, if
	 * COOP_TASKRUN is set, then IPIs are never needed by the app.
	 */
	ret = -EINVAL;
	if (ctx->flags & IORING_SETUP_SQPOLL) {
		/* IPI related flags don't make sense with SQPOLL */
		if (ctx->flags & (IORING_SETUP_COOP_TASKRUN |
				  IORING_SETUP_TASKRUN_FLAG |
				  IORING_SETUP_DEFER_TASKRUN))
			goto err;
		ctx->notify_method = TWA_SIGNAL_NO_IPI;
	} else if (ctx->flags & IORING_SETUP_COOP_TASKRUN) {
		ctx->notify_method = TWA_SIGNAL_NO_IPI;
	} else {
		if (ctx->flags & IORING_SETUP_TASKRUN_FLAG &&
		    !(ctx->flags & IORING_SETUP_DEFER_TASKRUN))
			goto err;
		ctx->notify_method = TWA_SIGNAL;
	}

	/*
	 * For DEFER_TASKRUN we require the completion task to be the same as the
	 * submission task. This implies that there is only one submitter, so enforce
	 * that.
	 */
	if (ctx->flags & IORING_SETUP_DEFER_TASKRUN &&
	    !(ctx->flags & IORING_SETUP_SINGLE_ISSUER)) {
		goto err;
	}

	/*
	 * This is just grabbed for accounting purposes. When a process exits,
	 * the mm is exited and dropped before the files, hence we need to hang
	 * on to this mm purely for the purposes of being able to unaccount
	 * memory (locked/pinned vm). It's not used for anything else.
	 */
	mmgrab(current->mm);
	ctx->mm_account = current->mm;

	ret = io_allocate_scq_urings(ctx, p);
	if (ret)
		goto err;

	ret = io_sq_offload_create(ctx, p);
	if (ret)
		goto err;

	ret = io_rsrc_init(ctx);
	if (ret)
		goto err;

	p->sq_off.head = offsetof(struct io_rings, sq.head);
	p->sq_off.tail = offsetof(struct io_rings, sq.tail);
	p->sq_off.ring_mask = offsetof(struct io_rings, sq_ring_mask);
	p->sq_off.ring_entries = offsetof(struct io_rings, sq_ring_entries);
	p->sq_off.flags = offsetof(struct io_rings, sq_flags);
	p->sq_off.dropped = offsetof(struct io_rings, sq_dropped);
	if (!(ctx->flags & IORING_SETUP_NO_SQARRAY))
		p->sq_off.array = (char *)ctx->sq_array - (char *)ctx->rings;
	p->sq_off.resv1 = 0;
	if (!(ctx->flags & IORING_SETUP_NO_MMAP))
		p->sq_off.user_addr = 0;

	p->cq_off.head = offsetof(struct io_rings, cq.head);
	p->cq_off.tail = offsetof(struct io_rings, cq.tail);
	p->cq_off.ring_mask = offsetof(struct io_rings, cq_ring_mask);
	p->cq_off.ring_entries = offsetof(struct io_rings, cq_ring_entries);
	p->cq_off.overflow = offsetof(struct io_rings, cq_overflow);
	p->cq_off.cqes = offsetof(struct io_rings, cqes);
	p->cq_off.flags = offsetof(struct io_rings, cq_flags);
	p->cq_off.resv1 = 0;
	if (!(ctx->flags & IORING_SETUP_NO_MMAP))
		p->cq_off.user_addr = 0;

	p->features = IORING_FEAT_SINGLE_MMAP | IORING_FEAT_NODROP |
			IORING_FEAT_SUBMIT_STABLE | IORING_FEAT_RW_CUR_POS |
			IORING_FEAT_CUR_PERSONALITY | IORING_FEAT_FAST_POLL |
			IORING_FEAT_POLL_32BITS | IORING_FEAT_SQPOLL_NONFIXED |
			IORING_FEAT_EXT_ARG | IORING_FEAT_NATIVE_WORKERS |
			IORING_FEAT_RSRC_TAGS | IORING_FEAT_CQE_SKIP |
			IORING_FEAT_LINKED_FILE | IORING_FEAT_REG_REG_RING;

	if (copy_to_user(params, p, sizeof(*p))) {
		ret = -EFAULT;
		goto err;
	}

	if (ctx->flags & IORING_SETUP_SINGLE_ISSUER
	    && !(ctx->flags & IORING_SETUP_R_DISABLED))
		WRITE_ONCE(ctx->submitter_task, get_task_struct(current));

	file = io_uring_get_file(ctx);
	if (IS_ERR(file)) {
		ret = PTR_ERR(file);
		goto err;
	}

	ret = __io_uring_add_tctx_node(ctx);
	if (ret)
		goto err_fput;
	tctx = current->io_uring;

	/*
	 * Install ring fd as the very last thing, so we don't risk someone
	 * having closed it before we finish setup
	 */
	if (p->flags & IORING_SETUP_REGISTERED_FD_ONLY)
		ret = io_ring_add_registered_file(tctx, file, 0, IO_RINGFD_REG_MAX);
	else
		ret = io_uring_install_fd(file);
	if (ret < 0)
		goto err_fput;

	trace_io_uring_create(ret, ctx, p->sq_entries, p->cq_entries, p->flags);
	return ret;
err:
	io_ring_ctx_wait_and_kill(ctx);
	return ret;
err_fput:
	fput(file);
	return ret;
}

/*
 * Sets up an aio uring context, and returns the fd. Applications asks for a
 * ring size, we return the actual sq/cq ring sizes (among other things) in the
 * params structure passed in.
 */
static long io_uring_setup(u32 entries, struct io_uring_params __user *params)
{
	struct io_uring_params p;
	int i;

	if (copy_from_user(&p, params, sizeof(p)))
		return -EFAULT;
	for (i = 0; i < ARRAY_SIZE(p.resv); i++) {
		if (p.resv[i])
			return -EINVAL;
	}

	if (p.flags & ~(IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL |
			IORING_SETUP_SQ_AFF | IORING_SETUP_CQSIZE |
			IORING_SETUP_CLAMP | IORING_SETUP_ATTACH_WQ |
			IORING_SETUP_R_DISABLED | IORING_SETUP_SUBMIT_ALL |
			IORING_SETUP_COOP_TASKRUN | IORING_SETUP_TASKRUN_FLAG |
			IORING_SETUP_SQE128 | IORING_SETUP_CQE32 |
			IORING_SETUP_SINGLE_ISSUER | IORING_SETUP_DEFER_TASKRUN |
			IORING_SETUP_NO_MMAP | IORING_SETUP_REGISTERED_FD_ONLY |
			IORING_SETUP_NO_SQARRAY))
		return -EINVAL;

	return io_uring_create(entries, &p, params);
}

static inline bool io_uring_allowed(void)
{
	int disabled = READ_ONCE(sysctl_io_uring_disabled);
	kgid_t io_uring_group;

	if (disabled == 2)
		return false;

	if (disabled == 0 || capable(CAP_SYS_ADMIN))
		return true;

	io_uring_group = make_kgid(&init_user_ns, sysctl_io_uring_group);
	if (!gid_valid(io_uring_group))
		return false;

	return in_group_p(io_uring_group);
}

SYSCALL_DEFINE2(io_uring_setup, u32, entries,
		struct io_uring_params __user *, params)
{
	if (!io_uring_allowed())
		return -EPERM;

	return io_uring_setup(entries, params);
}

static int __init io_uring_init(void)
{
#define __BUILD_BUG_VERIFY_OFFSET_SIZE(stype, eoffset, esize, ename) do { \
	BUILD_BUG_ON(offsetof(stype, ename) != eoffset); \
	BUILD_BUG_ON(sizeof_field(stype, ename) != esize); \
} while (0)

#define BUILD_BUG_SQE_ELEM(eoffset, etype, ename) \
	__BUILD_BUG_VERIFY_OFFSET_SIZE(struct io_uring_sqe, eoffset, sizeof(etype), ename)
#define BUILD_BUG_SQE_ELEM_SIZE(eoffset, esize, ename) \
	__BUILD_BUG_VERIFY_OFFSET_SIZE(struct io_uring_sqe, eoffset, esize, ename)
	BUILD_BUG_ON(sizeof(struct io_uring_sqe) != 64);
	BUILD_BUG_SQE_ELEM(0,  __u8,   opcode);
	BUILD_BUG_SQE_ELEM(1,  __u8,   flags);
	BUILD_BUG_SQE_ELEM(2,  __u16,  ioprio);
	BUILD_BUG_SQE_ELEM(4,  __s32,  fd);
	BUILD_BUG_SQE_ELEM(8,  __u64,  off);
	BUILD_BUG_SQE_ELEM(8,  __u64,  addr2);
	BUILD_BUG_SQE_ELEM(8,  __u32,  cmd_op);
	BUILD_BUG_SQE_ELEM(12, __u32, __pad1);
	BUILD_BUG_SQE_ELEM(16, __u64,  addr);
	BUILD_BUG_SQE_ELEM(16, __u64,  splice_off_in);
	BUILD_BUG_SQE_ELEM(24, __u32,  len);
	BUILD_BUG_SQE_ELEM(28,     __kernel_rwf_t, rw_flags);
	BUILD_BUG_SQE_ELEM(28, /* compat */   int, rw_flags);
	BUILD_BUG_SQE_ELEM(28, /* compat */ __u32, rw_flags);
	BUILD_BUG_SQE_ELEM(28, __u32,  fsync_flags);
	BUILD_BUG_SQE_ELEM(28, /* compat */ __u16,  poll_events);
	BUILD_BUG_SQE_ELEM(28, __u32,  poll32_events);
	BUILD_BUG_SQE_ELEM(28, __u32,  sync_range_flags);
	BUILD_BUG_SQE_ELEM(28, __u32,  msg_flags);
	BUILD_BUG_SQE_ELEM(28, __u32,  timeout_flags);
	BUILD_BUG_SQE_ELEM(28, __u32,  accept_flags);
	BUILD_BUG_SQE_ELEM(28, __u32,  cancel_flags);
	BUILD_BUG_SQE_ELEM(28, __u32,  open_flags);
	BUILD_BUG_SQE_ELEM(28, __u32,  statx_flags);
	BUILD_BUG_SQE_ELEM(28, __u32,  fadvise_advice);
	BUILD_BUG_SQE_ELEM(28, __u32,  splice_flags);
	BUILD_BUG_SQE_ELEM(28, __u32,  rename_flags);
	BUILD_BUG_SQE_ELEM(28, __u32,  unlink_flags);
	BUILD_BUG_SQE_ELEM(28, __u32,  hardlink_flags);
	BUILD_BUG_SQE_ELEM(28, __u32,  xattr_flags);
	BUILD_BUG_SQE_ELEM(28, __u32,  msg_ring_flags);
	BUILD_BUG_SQE_ELEM(32, __u64,  user_data);
	BUILD_BUG_SQE_ELEM(40, __u16,  buf_index);
	BUILD_BUG_SQE_ELEM(40, __u16,  buf_group);
	BUILD_BUG_SQE_ELEM(42, __u16,  personality);
	BUILD_BUG_SQE_ELEM(44, __s32,  splice_fd_in);
	BUILD_BUG_SQE_ELEM(44, __u32,  file_index);
	BUILD_BUG_SQE_ELEM(44, __u16,  addr_len);
	BUILD_BUG_SQE_ELEM(46, __u16,  __pad3[0]);
	BUILD_BUG_SQE_ELEM(48, __u64,  addr3);
	BUILD_BUG_SQE_ELEM_SIZE(48, 0, cmd);
	BUILD_BUG_SQE_ELEM(56, __u64,  __pad2);

	BUILD_BUG_ON(sizeof(struct io_uring_files_update) !=
		     sizeof(struct io_uring_rsrc_update));
	BUILD_BUG_ON(sizeof(struct io_uring_rsrc_update) >
		     sizeof(struct io_uring_rsrc_update2));

	/* ->buf_index is u16 */
	BUILD_BUG_ON(offsetof(struct io_uring_buf_ring, bufs) != 0);
	BUILD_BUG_ON(offsetof(struct io_uring_buf, resv) !=
		     offsetof(struct io_uring_buf_ring, tail));

	/* should fit into one byte */
	BUILD_BUG_ON(SQE_VALID_FLAGS >= (1 << 8));
	BUILD_BUG_ON(SQE_COMMON_FLAGS >= (1 << 8));
	BUILD_BUG_ON((SQE_VALID_FLAGS | SQE_COMMON_FLAGS) != SQE_VALID_FLAGS);

	BUILD_BUG_ON(__REQ_F_LAST_BIT > 8 * sizeof_field(struct io_kiocb, flags));

	BUILD_BUG_ON(sizeof(atomic_t) != sizeof(u32));

	/* top 8bits are for internal use */
	BUILD_BUG_ON((IORING_URING_CMD_MASK & 0xff000000) != 0);

	io_uring_optable_init();

	/*
	 * Allow user copy in the per-command field, which starts after the
	 * file in io_kiocb and until the opcode field. The openat2 handling
	 * requires copying in user memory into the io_kiocb object in that
	 * range, and HARDENED_USERCOPY will complain if we haven't
	 * correctly annotated this range.
	 */
	req_cachep = kmem_cache_create_usercopy("io_kiocb",
				sizeof(struct io_kiocb), 0,
				SLAB_HWCACHE_ALIGN | SLAB_PANIC |
				SLAB_ACCOUNT | SLAB_TYPESAFE_BY_RCU,
				offsetof(struct io_kiocb, cmd.data),
				sizeof_field(struct io_kiocb, cmd.data), NULL);
	io_buf_cachep = KMEM_CACHE(io_buffer,
					  SLAB_HWCACHE_ALIGN | SLAB_PANIC | SLAB_ACCOUNT);

	iou_wq = alloc_workqueue("iou_exit", WQ_UNBOUND, 64);

#ifdef CONFIG_SYSCTL
	register_sysctl_init("kernel", kernel_io_uring_disabled_table);
#endif

	return 0;
};
__initcall(io_uring_init);