block/blk-mq-cpu.c

   1 #include <linux/kernel.h>
   2 #include <linux/module.h>
   3 #include <linux/init.h>
   4 #include <linux/blkdev.h>
   5 #include <linux/list.h>
   6 #include <linux/llist.h>
   7 #include <linux/smp.h>
   8 #include <linux/cpu.h>
   9
  10 #include <linux/blk-mq.h>
  11 #include "blk-mq.h"
  12
  13 static LIST_HEAD(blk_mq_cpu_notify_list);
  14 static DEFINE_SPINLOCK(blk_mq_cpu_notify_lock);
  15
  16 static int blk_mq_main_cpu_notify(struct notifier_block *self,
  17                                   unsigned long action, void *hcpu)
  18 {
  19         unsigned int cpu = (unsigned long) hcpu;
  20         struct blk_mq_cpu_notifier *notify;
  21
  22         spin_lock(&blk_mq_cpu_notify_lock);
  23
  24         list_for_each_entry(notify, &blk_mq_cpu_notify_list, list)
  25                 notify->notify(notify->data, action, cpu);
  26
  27         spin_unlock(&blk_mq_cpu_notify_lock);
  28         return NOTIFY_OK;
  29 }
  30
  31 static void blk_mq_cpu_notify(void *data, unsigned long action,
  32                               unsigned int cpu)
  33 {
  34         if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
  35                 /*
  36                  * If the CPU goes away, ensure that we run any pending
  37                  * completions.
  38                  */
  39                 struct llist_node *node;
  40                 struct request *rq;
  41
  42                 local_irq_disable();
  43
  44                 node = llist_del_all(&per_cpu(ipi_lists, cpu));
  45                 while (node) {
  46                         struct llist_node *next = node->next;
  47
  48                         rq = llist_entry(node, struct request, ll_list);
  49                         __blk_mq_end_io(rq, rq->errors);
  50                         node = next;
  51                 }
  52
  53                 local_irq_enable();
  54         }
  55 }
  56
  57 static struct notifier_block __cpuinitdata blk_mq_main_cpu_notifier = {
  58         .notifier_call  = blk_mq_main_cpu_notify,
  59 };
  60
  61 void blk_mq_register_cpu_notifier(struct blk_mq_cpu_notifier *notifier)
  62 {
  63         BUG_ON(!notifier->notify);
  64
  65         spin_lock(&blk_mq_cpu_notify_lock);
  66         list_add_tail(&notifier->list, &blk_mq_cpu_notify_list);
  67         spin_unlock(&blk_mq_cpu_notify_lock);
  68 }
  69
  70 void blk_mq_unregister_cpu_notifier(struct blk_mq_cpu_notifier *notifier)
  71 {
  72         spin_lock(&blk_mq_cpu_notify_lock);
  73         list_del(&notifier->list);
  74         spin_unlock(&blk_mq_cpu_notify_lock);
  75 }
  76
  77 void blk_mq_init_cpu_notifier(struct blk_mq_cpu_notifier *notifier,
  78                               void (*fn)(void *, unsigned long, unsigned int),
  79                               void *data)
  80 {
  81         notifier->notify = fn;
  82         notifier->data = data;
  83 }
  84
  85 static struct blk_mq_cpu_notifier __cpuinitdata cpu_notifier = {
  86         .notify = blk_mq_cpu_notify,
  87 };
  88
  89 void __init blk_mq_cpu_init(void)
  90 {
  91         register_hotcpu_notifier(&blk_mq_main_cpu_notifier);
  92         blk_mq_register_cpu_notifier(&cpu_notifier);
  93 }