#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 */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