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-rw-r--r--drivers/block/zram/zram_drv.h143
1 files changed, 143 insertions, 0 deletions
diff --git a/drivers/block/zram/zram_drv.h b/drivers/block/zram/zram_drv.h
new file mode 100644
index 0000000000..ca7a15bd48
--- /dev/null
+++ b/drivers/block/zram/zram_drv.h
@@ -0,0 +1,143 @@
+/*
+ * Compressed RAM block device
+ *
+ * Copyright (C) 2008, 2009, 2010 Nitin Gupta
+ * 2012, 2013 Minchan Kim
+ *
+ * This code is released using a dual license strategy: BSD/GPL
+ * You can choose the licence that better fits your requirements.
+ *
+ * Released under the terms of 3-clause BSD License
+ * Released under the terms of GNU General Public License Version 2.0
+ *
+ */
+
+#ifndef _ZRAM_DRV_H_
+#define _ZRAM_DRV_H_
+
+#include <linux/rwsem.h>
+#include <linux/zsmalloc.h>
+#include <linux/crypto.h>
+
+#include "zcomp.h"
+
+#define SECTORS_PER_PAGE_SHIFT (PAGE_SHIFT - SECTOR_SHIFT)
+#define SECTORS_PER_PAGE (1 << SECTORS_PER_PAGE_SHIFT)
+#define ZRAM_LOGICAL_BLOCK_SHIFT 12
+#define ZRAM_LOGICAL_BLOCK_SIZE (1 << ZRAM_LOGICAL_BLOCK_SHIFT)
+#define ZRAM_SECTOR_PER_LOGICAL_BLOCK \
+ (1 << (ZRAM_LOGICAL_BLOCK_SHIFT - SECTOR_SHIFT))
+
+
+/*
+ * ZRAM is mainly used for memory efficiency so we want to keep memory
+ * footprint small and thus squeeze size and zram pageflags into a flags
+ * member. The lower ZRAM_FLAG_SHIFT bits is for object size (excluding
+ * header), which cannot be larger than PAGE_SIZE (requiring PAGE_SHIFT
+ * bits), the higher bits are for zram_pageflags.
+ *
+ * We use BUILD_BUG_ON() to make sure that zram pageflags don't overflow.
+ */
+#define ZRAM_FLAG_SHIFT (PAGE_SHIFT + 1)
+
+/* Only 2 bits are allowed for comp priority index */
+#define ZRAM_COMP_PRIORITY_MASK 0x3
+
+/* Flags for zram pages (table[page_no].flags) */
+enum zram_pageflags {
+ /* zram slot is locked */
+ ZRAM_LOCK = ZRAM_FLAG_SHIFT,
+ ZRAM_SAME, /* Page consists the same element */
+ ZRAM_WB, /* page is stored on backing_device */
+ ZRAM_UNDER_WB, /* page is under writeback */
+ ZRAM_HUGE, /* Incompressible page */
+ ZRAM_IDLE, /* not accessed page since last idle marking */
+ ZRAM_INCOMPRESSIBLE, /* none of the algorithms could compress it */
+
+ ZRAM_COMP_PRIORITY_BIT1, /* First bit of comp priority index */
+ ZRAM_COMP_PRIORITY_BIT2, /* Second bit of comp priority index */
+
+ __NR_ZRAM_PAGEFLAGS,
+};
+
+/*-- Data structures */
+
+/* Allocated for each disk page */
+struct zram_table_entry {
+ union {
+ unsigned long handle;
+ unsigned long element;
+ };
+ unsigned long flags;
+#ifdef CONFIG_ZRAM_MEMORY_TRACKING
+ ktime_t ac_time;
+#endif
+};
+
+struct zram_stats {
+ atomic64_t compr_data_size; /* compressed size of pages stored */
+ atomic64_t failed_reads; /* can happen when memory is too low */
+ atomic64_t failed_writes; /* can happen when memory is too low */
+ atomic64_t notify_free; /* no. of swap slot free notifications */
+ atomic64_t same_pages; /* no. of same element filled pages */
+ atomic64_t huge_pages; /* no. of huge pages */
+ atomic64_t huge_pages_since; /* no. of huge pages since zram set up */
+ atomic64_t pages_stored; /* no. of pages currently stored */
+ atomic_long_t max_used_pages; /* no. of maximum pages stored */
+ atomic64_t writestall; /* no. of write slow paths */
+ atomic64_t miss_free; /* no. of missed free */
+#ifdef CONFIG_ZRAM_WRITEBACK
+ atomic64_t bd_count; /* no. of pages in backing device */
+ atomic64_t bd_reads; /* no. of reads from backing device */
+ atomic64_t bd_writes; /* no. of writes from backing device */
+#endif
+};
+
+#ifdef CONFIG_ZRAM_MULTI_COMP
+#define ZRAM_PRIMARY_COMP 0U
+#define ZRAM_SECONDARY_COMP 1U
+#define ZRAM_MAX_COMPS 4U
+#else
+#define ZRAM_PRIMARY_COMP 0U
+#define ZRAM_SECONDARY_COMP 0U
+#define ZRAM_MAX_COMPS 1U
+#endif
+
+struct zram {
+ struct zram_table_entry *table;
+ struct zs_pool *mem_pool;
+ struct zcomp *comps[ZRAM_MAX_COMPS];
+ struct gendisk *disk;
+ /* Prevent concurrent execution of device init */
+ struct rw_semaphore init_lock;
+ /*
+ * the number of pages zram can consume for storing compressed data
+ */
+ unsigned long limit_pages;
+
+ struct zram_stats stats;
+ /*
+ * This is the limit on amount of *uncompressed* worth of data
+ * we can store in a disk.
+ */
+ u64 disksize; /* bytes */
+ const char *comp_algs[ZRAM_MAX_COMPS];
+ s8 num_active_comps;
+ /*
+ * zram is claimed so open request will be failed
+ */
+ bool claim; /* Protected by disk->open_mutex */
+#ifdef CONFIG_ZRAM_WRITEBACK
+ struct file *backing_dev;
+ spinlock_t wb_limit_lock;
+ bool wb_limit_enable;
+ u64 bd_wb_limit;
+ struct block_device *bdev;
+ unsigned long *bitmap;
+ unsigned long nr_pages;
+#endif
+#ifdef CONFIG_ZRAM_MEMORY_TRACKING
+ struct dentry *debugfs_dir;
+#endif
+};
+#endif