summaryrefslogblamecommitdiffstats
path: root/include/linux/blockgroup_lock.h
blob: 511ab123a8223493f8c15ee5dbc683f2ca747dd2 (plain) (tree)
1
2
3
4
5
6
7
8
9
                                      







                                            



                           
                                                                 
     
                         
      
















                                                             


                                                                   
                                                               
 

      
/* SPDX-License-Identifier: GPL-2.0 */
#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