blob: 8607312983bd8045c24a402335b30ee034c4505c (
plain) (
blame)
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
|
#ifndef _LINUX_BLOCKGROUP_LOCK_H
#define _LINUX_BLOCKGROUP_LOCK_H
/*
* Per-blockgroup locking for ext2 and ext3.
*
* Simple hashed spinlocking.
*/
#include <linux/spinlock.h>
#include <linux/cache.h>
#ifdef CONFIG_SMP
/*
* We want a power-of-two. Is there a better way than this?
*/
#if NR_CPUS >= 32
#define NR_BG_LOCKS 128
#elif NR_CPUS >= 16
#define NR_BG_LOCKS 64
#elif NR_CPUS >= 8
#define NR_BG_LOCKS 32
#elif NR_CPUS >= 4
#define NR_BG_LOCKS 16
#elif NR_CPUS >= 2
#define NR_BG_LOCKS 8
#else
#define NR_BG_LOCKS 4
#endif
#else /* CONFIG_SMP */
#define NR_BG_LOCKS 1
#endif /* CONFIG_SMP */
struct bgl_lock {
spinlock_t lock;
} ____cacheline_aligned_in_smp;
struct blockgroup_lock {
struct bgl_lock locks[NR_BG_LOCKS];
};
static inline void bgl_lock_init(struct blockgroup_lock *bgl)
{
int i;
for (i = 0; i < NR_BG_LOCKS; i++)
spin_lock_init(&bgl->locks[i].lock);
}
/*
* The accessor is a macro so we can embed a blockgroup_lock into different
* superblock types
*/
#define sb_bgl_lock(sb, block_group) \
(&(sb)->s_blockgroup_lock.locks[(block_group) & (NR_BG_LOCKS-1)].lock)
#endif
|
