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 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 34 static inline spinlock_t * 35 bgl_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 41