linux-imx

/*

 *  linux/fs/buffer.c

 *

 *  Copyright (C) 1991, 1992, 2002  Linus Torvalds

 */

​

/*

 * Start bdflush() with kernel_thread not syscall - Paul Gortmaker, 12/95

 *

 * Removed a lot of unnecessary code and simplified things now that

 * the buffer cache isn't our primary cache - Andrew Tridgell 12/96

 *

 * Speed up hash, lru, and free list operations.  Use gfp() for allocating

 * hash table, use SLAB cache for buffer heads. SMP threading.  -DaveM

 *

 * Added 32k buffer block sizes - these are required older ARM systems. - RMK

 *

 * async buffer flushing, 1999 Andrea Arcangeli <andrea@suse.de>

 */

​

#include <linux/kernel.h>

#include <linux/sched/signal.h>

#include <linux/syscalls.h>

#include <linux/fs.h>

#include <linux/iomap.h>

#include <linux/mm.h>

#include <linux/percpu.h>

#include <linux/slab.h>

#include <linux/capability.h>

#include <linux/blkdev.h>

#include <linux/file.h>

#include <linux/quotaops.h>

#include <linux/highmem.h>

#include <linux/export.h>

#include <linux/backing-dev.h>

#include <linux/writeback.h>

#include <linux/hash.h>

#include <linux/suspend.h>

#include <linux/buffer_head.h>

#include <linux/task_io_accounting_ops.h>

#include <linux/bio.h>

#include <linux/cpu.h>

#include <linux/bitops.h>

#include <linux/mpage.h>

#include <linux/bit_spinlock.h>

#include <linux/pagevec.h>

#include <linux/sched/mm.h>

#include <trace/events/block.h>

​

static int fsync_buffers_list(spinlock_t *lock, struct list_head *list);

static int submit_bh_wbc(int op, int op_flags, struct buffer_head *bh,

             enum rw_hint hint, struct writeback_control *wbc);

​

#define BH_ENTRY(list) list_entry((list), struct buffer_head, b_assoc_buffers)

​

inline void touch_buffer(struct buffer_head *bh)

{

    trace_block_touch_buffer(bh);

    mark_page_accessed(bh->b_page);

}

EXPORT_SYMBOL(touch_buffer);

​

void __lock_buffer(struct buffer_head *bh)

{

    wait_on_bit_lock_io(&bh->b_state, BH_Lock, TASK_UNINTERRUPTIBLE);

}

EXPORT_SYMBOL(__lock_buffer);

​

void unlock_buffer(struct buffer_head *bh)

{

    clear_bit_unlock(BH_Lock, &bh->b_state);

    smp_mb__after_atomic();

    wake_up_bit(&bh->b_state, BH_Lock);

}

EXPORT_SYMBOL(unlock_buffer);

​

/*

 * Returns if the page has dirty or writeback buffers. If all the buffers

 * are unlocked and clean then the PageDirty information is stale. If

 * any of the pages are locked, it is assumed they are locked for IO.

 */

void buffer_check_dirty_writeback(struct page *page,

                     bool *dirty, bool *writeback)

{

    struct buffer_head *head, *bh;

    *dirty = false;

    *writeback = false;

​

    BUG_ON(!PageLocked(page));

​

    if (!page_has_buffers(page))

        return;