| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 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 | |
| 64 | void __init blk_mq_cpu_init(void) |
| 65 | { |
| 66 | hotcpu_notifier(blk_mq_main_cpu_notify, 0); |
| 67 | } |