LXR linux/block/blk-mq-cpu.c

   1/*
   2 * CPU notifier helper code for blk-mq
   3 *
   4 * Copyright (C) 2013-2014 Jens Axboe
   5 */
   6#include <linux/kernel.h>
   7#include <linux/module.h>
   8#include <linux/init.h>
   9#include <linux/blkdev.h>
  10#include <linux/list.h>
  11#include <linux/llist.h>
  12#include <linux/smp.h>
  13#include <linux/cpu.h>
  14
  15#include <linux/blk-mq.h>
  16#include "blk-mq.h"
  17
  18static LIST_HEAD(blk_mq_cpu_notify_list);
  19static DEFINE_RAW_SPINLOCK(blk_mq_cpu_notify_lock);
  20
  21static int blk_mq_main_cpu_notify(struct notifier_block *self,
  22                                  unsigned long action, void *hcpu)
  23{
  24        unsigned int cpu = (unsigned long) hcpu;
  25        struct blk_mq_cpu_notifier *notify;
  26        int ret = NOTIFY_OK;
  27
  28        raw_spin_lock(&blk_mq_cpu_notify_lock);
  29
  30        list_for_each_entry(notify, &blk_mq_cpu_notify_list, list) {
  31                ret = notify->notify(notify->data, action, cpu);
  32                if (ret != NOTIFY_OK)
  33                        break;
  34        }
  35
  36        raw_spin_unlock(&blk_mq_cpu_notify_lock);
  37        return ret;
  38}
  39
  40void blk_mq_register_cpu_notifier(struct blk_mq_cpu_notifier *notifier)
  41{
  42        BUG_ON(!notifier->notify);
  43
  44        raw_spin_lock(&blk_mq_cpu_notify_lock);
  45        list_add_tail(&notifier->list, &blk_mq_cpu_notify_list);
  46        raw_spin_unlock(&blk_mq_cpu_notify_lock);
  47}
  48
  49void blk_mq_unregister_cpu_notifier(struct blk_mq_cpu_notifier *notifier)
  50{
  51        raw_spin_lock(&blk_mq_cpu_notify_lock);
  52        list_del(&notifier->list);
  53        raw_spin_unlock(&blk_mq_cpu_notify_lock);
  54}
  55
  56void blk_mq_init_cpu_notifier(struct blk_mq_cpu_notifier *notifier,
  57                              int (*fn)(void *, unsigned long, unsigned int),
  58                              void *data)
  59{
  60        notifier->notify = fn;
  61        notifier->data = data;
  62}
  63
  64void __init blk_mq_cpu_init(void)
  65{
  66        hotcpu_notifier(blk_mq_main_cpu_notify, 0);
  67}
  68