2 * CPU notifier helper code for blk-mq
4 * Copyright (C) 2013-2014 Jens Axboe
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>
15 #include <linux/blk-mq.h>
18 static LIST_HEAD(blk_mq_cpu_notify_list);
19 static DEFINE_SPINLOCK(blk_mq_cpu_notify_lock);
21 static int blk_mq_main_cpu_notify(struct notifier_block *self,
22 unsigned long action, void *hcpu)
24 unsigned int cpu = (unsigned long) hcpu;
25 struct blk_mq_cpu_notifier *notify;
28 if (action != CPU_POST_DEAD)
31 spin_lock(&blk_mq_cpu_notify_lock);
33 list_for_each_entry(notify, &blk_mq_cpu_notify_list, list) {
34 ret = notify->notify(notify->data, action, cpu);
39 spin_unlock(&blk_mq_cpu_notify_lock);
43 void blk_mq_register_cpu_notifier(struct blk_mq_cpu_notifier *notifier)
45 BUG_ON(!notifier->notify);
47 spin_lock(&blk_mq_cpu_notify_lock);
48 list_add_tail(¬ifier->list, &blk_mq_cpu_notify_list);
49 spin_unlock(&blk_mq_cpu_notify_lock);
52 void blk_mq_unregister_cpu_notifier(struct blk_mq_cpu_notifier *notifier)
54 spin_lock(&blk_mq_cpu_notify_lock);
55 list_del(¬ifier->list);
56 spin_unlock(&blk_mq_cpu_notify_lock);
59 void blk_mq_init_cpu_notifier(struct blk_mq_cpu_notifier *notifier,
60 int (*fn)(void *, unsigned long, unsigned int),
63 notifier->notify = fn;
64 notifier->data = data;
67 void __init blk_mq_cpu_init(void)
69 hotcpu_notifier(blk_mq_main_cpu_notify, 0);