/* * CPU notifier helper code for blk-mq * * Copyright (C) 2013-2014 Jens Axboe */ #include <linux/kernel.h> #include <linux/module.h> #include <linux/init.h> #include <linux/blkdev.h> #include <linux/list.h> #include <linux/llist.h> #include <linux/smp.h> #include <linux/cpu.h> #include <linux/blk-mq.h> #include "blk-mq.h" static LIST_HEAD(blk_mq_cpu_notify_list); static DEFINE_RAW_SPINLOCK(blk_mq_cpu_notify_lock); static int blk_mq_main_cpu_notify(struct notifier_block *self, unsigned long action, void *hcpu) { unsigned int cpu = (unsigned long) hcpu; struct blk_mq_cpu_notifier *notify; int ret = NOTIFY_OK; raw_spin_lock(&blk_mq_cpu_notify_lock); list_for_each_entry(notify, &blk_mq_cpu_notify_list, list) { ret = notify->notify(notify->data, action, cpu); if (ret != NOTIFY_OK) break; } raw_spin_unlock(&blk_mq_cpu_notify_lock); return ret; } void blk_mq_register_cpu_notifier(struct blk_mq_cpu_notifier *notifier) { BUG_ON(!notifier->notify); raw_spin_lock(&blk_mq_cpu_notify_lock); list_add_tail(¬ifier->list, &blk_mq_cpu_notify_list); raw_spin_unlock(&blk_mq_cpu_notify_lock); } void blk_mq_unregister_cpu_notifier(struct blk_mq_cpu_notifier *notifier) { raw_spin_lock(&blk_mq_cpu_notify_lock); list_del(¬ifier->list); raw_spin_unlock(&blk_mq_cpu_notify_lock); } void blk_mq_init_cpu_notifier(struct blk_mq_cpu_notifier *notifier, int (*fn)(void *, unsigned long, unsigned int), void *data) { notifier->notify = fn; notifier->data = data; } void __init blk_mq_cpu_init(void) { hotcpu_notifier(blk_mq_main_cpu_notify, 0); }