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
18 static LIST_HEAD(blk_mq_cpu_notify_list);
19 static DEFINE_RAW_SPINLOCK(blk_mq_cpu_notify_lock);
20
blk_mq_main_cpu_notify(struct notifier_block * self,unsigned long action,void * hcpu)21 static 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
blk_mq_register_cpu_notifier(struct blk_mq_cpu_notifier * notifier)40 void 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(¬ifier->list, &blk_mq_cpu_notify_list);
46 raw_spin_unlock(&blk_mq_cpu_notify_lock);
47 }
48
blk_mq_unregister_cpu_notifier(struct blk_mq_cpu_notifier * notifier)49 void blk_mq_unregister_cpu_notifier(struct blk_mq_cpu_notifier *notifier)
50 {
51 raw_spin_lock(&blk_mq_cpu_notify_lock);
52 list_del(¬ifier->list);
53 raw_spin_unlock(&blk_mq_cpu_notify_lock);
54 }
55
blk_mq_init_cpu_notifier(struct blk_mq_cpu_notifier * notifier,int (* fn)(void *,unsigned long,unsigned int),void * data)56 void 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
blk_mq_cpu_init(void)64 void __init blk_mq_cpu_init(void)
65 {
66 hotcpu_notifier(blk_mq_main_cpu_notify, 0);
67 }
68