Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
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linux
1#ifndef _LINUX_BLOCKGROUP_LOCK_H
2#define _LINUX_BLOCKGROUP_LOCK_H
3/*
4 * Per-blockgroup locking for ext2 and ext3.
5 *
6 * Simple hashed spinlocking.
7 */
8
9#include <linux/spinlock.h>
10#include <linux/cache.h>
11
12#ifdef CONFIG_SMP
13#define NR_BG_LOCKS (4 << ilog2(NR_CPUS < 32 ? NR_CPUS : 32))
14#else
15#define NR_BG_LOCKS 1
16#endif
17
18struct bgl_lock {
19 spinlock_t lock;
20} ____cacheline_aligned_in_smp;
21
22struct blockgroup_lock {
23 struct bgl_lock locks[NR_BG_LOCKS];
24};
25
26static inline void bgl_lock_init(struct blockgroup_lock *bgl)
27{
28 int i;
29
30 for (i = 0; i < NR_BG_LOCKS; i++)
31 spin_lock_init(&bgl->locks[i].lock);
32}
33
34static inline spinlock_t *
35bgl_lock_ptr(struct blockgroup_lock *bgl, unsigned int block_group)
36{
37 return &bgl->locks[block_group & (NR_BG_LOCKS-1)].lock;
38}
39
40#endif