| #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 |
| #define NR_BG_LOCKS (4 << ilog2(NR_CPUS < 32 ? NR_CPUS : 32)) |
| #else |
| #define NR_BG_LOCKS 1 |
| #endif |
| |
| 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); |
| } |
| |
| static inline spinlock_t * |
| bgl_lock_ptr(struct blockgroup_lock *bgl, unsigned int block_group) |
| { |
| return &bgl->locks[block_group & (NR_BG_LOCKS-1)].lock; |
| } |
| |
| #endif |