Root/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

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