[mirror_ubuntu-artful-kernel.git] / include / linux / blockgroup_lock.h

#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
Commit	Line	Data
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
1da177e4 LT	40	#endif