blockgroup_lock.h

 1/* SPDX-License-Identifier: GPL-2.0 */
 2#ifndef _LINUX_BLOCKGROUP_LOCK_H
 3#define _LINUX_BLOCKGROUP_LOCK_H
 4/*
 5 * Per-blockgroup locking for ext2 and ext3.
 6 *
 7 * Simple hashed spinlocking.
 8 */
 9
10#include <linux/spinlock.h>
11#include <linux/cache.h>
12
13#ifdef CONFIG_SMP
14#define NR_BG_LOCKS	(4 << ilog2(NR_CPUS < 32 ? NR_CPUS : 32))
15#else
16#define NR_BG_LOCKS	1
17#endif
18
19struct bgl_lock {
20	spinlock_t lock;
21} ____cacheline_aligned_in_smp;
22
23struct blockgroup_lock {
24	struct bgl_lock locks[NR_BG_LOCKS];
25};
26
27static inline void bgl_lock_init(struct blockgroup_lock *bgl)
28{
29	int i;
30
31	for (i = 0; i < NR_BG_LOCKS; i++)
32		spin_lock_init(&bgl->locks[i].lock);
33}
34
35static inline spinlock_t *
36bgl_lock_ptr(struct blockgroup_lock *bgl, unsigned int block_group)
37{
38	return &bgl->locks[block_group & (NR_BG_LOCKS-1)].lock;
39}
40
41#endif