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
|
From dbd55916b6a3efb4b812322d7502b174b4cceb69 Mon Sep 17 00:00:00 2001
From: Thomas Gleixner <tglx@linutronix.de>
Date: Thu, 12 Oct 2017 16:14:22 +0200
Subject: [PATCH 167/323] locking/rtmutex: Provide rt_mutex_slowlock_locked()
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/5.10/older/patches-5.10.204-rt100.tar.xz
This is the inner-part of rt_mutex_slowlock(), required for rwsem-rt.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
---
kernel/locking/rtmutex.c | 67 +++++++++++++++++++--------------
kernel/locking/rtmutex_common.h | 7 ++++
2 files changed, 45 insertions(+), 29 deletions(-)
diff --git a/kernel/locking/rtmutex.c b/kernel/locking/rtmutex.c
index c3f3c23fefef..395a3e8b2463 100644
--- a/kernel/locking/rtmutex.c
+++ b/kernel/locking/rtmutex.c
@@ -1234,35 +1234,16 @@ static void rt_mutex_handle_deadlock(int res, int detect_deadlock,
}
}
-/*
- * Slow path lock function:
- */
-static int __sched
-rt_mutex_slowlock(struct rt_mutex *lock, int state,
- struct hrtimer_sleeper *timeout,
- enum rtmutex_chainwalk chwalk)
+int __sched rt_mutex_slowlock_locked(struct rt_mutex *lock, int state,
+ struct hrtimer_sleeper *timeout,
+ enum rtmutex_chainwalk chwalk,
+ struct rt_mutex_waiter *waiter)
{
- struct rt_mutex_waiter waiter;
- unsigned long flags;
- int ret = 0;
-
- rt_mutex_init_waiter(&waiter);
-
- /*
- * Technically we could use raw_spin_[un]lock_irq() here, but this can
- * be called in early boot if the cmpxchg() fast path is disabled
- * (debug, no architecture support). In this case we will acquire the
- * rtmutex with lock->wait_lock held. But we cannot unconditionally
- * enable interrupts in that early boot case. So we need to use the
- * irqsave/restore variants.
- */
- raw_spin_lock_irqsave(&lock->wait_lock, flags);
+ int ret;
/* Try to acquire the lock again: */
- if (try_to_take_rt_mutex(lock, current, NULL)) {
- raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
+ if (try_to_take_rt_mutex(lock, current, NULL))
return 0;
- }
set_current_state(state);
@@ -1270,16 +1251,16 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
if (unlikely(timeout))
hrtimer_start_expires(&timeout->timer, HRTIMER_MODE_ABS);
- ret = task_blocks_on_rt_mutex(lock, &waiter, current, chwalk);
+ ret = task_blocks_on_rt_mutex(lock, waiter, current, chwalk);
if (likely(!ret))
/* sleep on the mutex */
- ret = __rt_mutex_slowlock(lock, state, timeout, &waiter);
+ ret = __rt_mutex_slowlock(lock, state, timeout, waiter);
if (unlikely(ret)) {
__set_current_state(TASK_RUNNING);
- remove_waiter(lock, &waiter);
- rt_mutex_handle_deadlock(ret, chwalk, &waiter);
+ remove_waiter(lock, waiter);
+ rt_mutex_handle_deadlock(ret, chwalk, waiter);
}
/*
@@ -1287,6 +1268,34 @@ rt_mutex_slowlock(struct rt_mutex *lock, int state,
* unconditionally. We might have to fix that up.
*/
fixup_rt_mutex_waiters(lock);
+ return ret;
+}
+
+/*
+ * Slow path lock function:
+ */
+static int __sched
+rt_mutex_slowlock(struct rt_mutex *lock, int state,
+ struct hrtimer_sleeper *timeout,
+ enum rtmutex_chainwalk chwalk)
+{
+ struct rt_mutex_waiter waiter;
+ unsigned long flags;
+ int ret = 0;
+
+ rt_mutex_init_waiter(&waiter);
+
+ /*
+ * Technically we could use raw_spin_[un]lock_irq() here, but this can
+ * be called in early boot if the cmpxchg() fast path is disabled
+ * (debug, no architecture support). In this case we will acquire the
+ * rtmutex with lock->wait_lock held. But we cannot unconditionally
+ * enable interrupts in that early boot case. So we need to use the
+ * irqsave/restore variants.
+ */
+ raw_spin_lock_irqsave(&lock->wait_lock, flags);
+
+ ret = rt_mutex_slowlock_locked(lock, state, timeout, chwalk, &waiter);
raw_spin_unlock_irqrestore(&lock->wait_lock, flags);
diff --git a/kernel/locking/rtmutex_common.h b/kernel/locking/rtmutex_common.h
index 37cd6b3bf6f4..b5a2affa59d5 100644
--- a/kernel/locking/rtmutex_common.h
+++ b/kernel/locking/rtmutex_common.h
@@ -15,6 +15,7 @@
#include <linux/rtmutex.h>
#include <linux/sched/wake_q.h>
+#include <linux/sched/debug.h>
/*
* This is the control structure for tasks blocked on a rt_mutex,
@@ -153,6 +154,12 @@ extern bool __rt_mutex_futex_unlock(struct rt_mutex *lock,
struct wake_q_head *wqh);
extern void rt_mutex_postunlock(struct wake_q_head *wake_q);
+/* RW semaphore special interface */
+
+int __sched rt_mutex_slowlock_locked(struct rt_mutex *lock, int state,
+ struct hrtimer_sleeper *timeout,
+ enum rtmutex_chainwalk chwalk,
+ struct rt_mutex_waiter *waiter);
#ifdef CONFIG_DEBUG_RT_MUTEXES
# include "rtmutex-debug.h"
--
2.43.0
|
