LXR linux/include/linux/blockgroup

   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
  42