locks.h

来自「嵌入式ARM的一些源代码」· C头文件 代码 · 共 66 行

#ifndef _LINUX_LOCKS_H
#define _LINUX_LOCKS_H

#ifndef _LINUX_MM_H
#include <linux/mm.h>
#endif
#ifndef _LINUX_PAGEMAP_H
#include <linux/pagemap.h>
#endif

/*
 * Unlocked, temporary IO buffer_heads gets moved to the reuse_list
 * once their page becomes unlocked.  
 */
extern struct buffer_head *reuse_list;

/*
 * Buffer cache locking - note that interrupts may only unlock, not
 * lock buffers.
 */
extern void __wait_on_buffer(struct buffer_head *);

extern inline void wait_on_buffer(struct buffer_head * bh)
{
	if (test_bit(BH_Lock, &bh->b_state))
		__wait_on_buffer(bh);
}

extern inline void lock_buffer(struct buffer_head * bh)
{
	while (set_bit(BH_Lock, &bh->b_state))
		__wait_on_buffer(bh);
}

void unlock_buffer(struct buffer_head *);


/*
 * super-block locking. Again, interrupts may only unlock
 * a super-block (although even this isn't done right now.
 * nfs may need it).
 */
extern void __wait_on_super(struct super_block *);

extern inline void wait_on_super(struct super_block * sb)
{
	if (sb->s_lock)
		__wait_on_super(sb);
}

extern inline void lock_super(struct super_block * sb)
{
	if (sb->s_lock)
		__wait_on_super(sb);
	sb->s_lock = 1;
}

extern inline void unlock_super(struct super_block * sb)
{
	sb->s_lock = 0;
	wake_up(&sb->s_wait);
}

#endif /* _LINUX_LOCKS_H */