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1da177e4 LT |
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 | ||
1da177e4 LT |
9 | #include <linux/spinlock.h> |
10 | #include <linux/cache.h> | |
11 | ||
12 | #ifdef CONFIG_SMP | |
7c5f6b32 | 13 | #define NR_BG_LOCKS (4 << ilog2(NR_CPUS < 32 ? NR_CPUS : 32)) |
1da177e4 | 14 | #else |
1da177e4 | 15 | #define NR_BG_LOCKS 1 |
7c5f6b32 | 16 | #endif |
1da177e4 LT |
17 | |
18 | struct bgl_lock { | |
19 | spinlock_t lock; | |
20 | } ____cacheline_aligned_in_smp; | |
21 | ||
22 | struct blockgroup_lock { | |
23 | struct bgl_lock locks[NR_BG_LOCKS]; | |
24 | }; | |
25 | ||
26 | static 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 | ||
c644f0e4 PE |
34 | static inline spinlock_t * |
35 | bgl_lock_ptr(struct blockgroup_lock *bgl, unsigned int block_group) | |
36 | { | |
9e5ab85d | 37 | return &bgl->locks[block_group & (NR_BG_LOCKS-1)].lock; |
c644f0e4 | 38 | } |
1da177e4 LT |
39 | |
40 | #endif |