drivers/xen/blktap2/wait_queue.c

   1 #include <linux/list.h>
   2 #include <linux/spinlock.h>
   3
   4 #include "blktap.h"
   5
   6 static LIST_HEAD(deferred_work_queue);
   7 static DEFINE_SPINLOCK(deferred_work_lock);
   8
   9 void
  10 blktap_run_deferred(void)
  11 {
  12         LIST_HEAD(queue);
  13         struct blktap *tap;
  14         unsigned long flags;
  15
  16         spin_lock_irqsave(&deferred_work_lock, flags);
  17         list_splice_init(&deferred_work_queue, &queue);
  18         list_for_each_entry(tap, &queue, deferred_queue)
  19                 clear_bit(BLKTAP_DEFERRED, &tap->dev_inuse);
  20         spin_unlock_irqrestore(&deferred_work_lock, flags);
  21
  22         while (!list_empty(&queue)) {
  23                 tap = list_entry(queue.next, struct blktap, deferred_queue);
  24                 list_del_init(&tap->deferred_queue);
  25                 blktap_device_restart(tap);
  26         }
  27 }
  28
  29 void
  30 blktap_defer(struct blktap *tap)
  31 {
  32         unsigned long flags;
  33
  34         spin_lock_irqsave(&deferred_work_lock, flags);
  35         if (!test_bit(BLKTAP_DEFERRED, &tap->dev_inuse)) {
  36                 set_bit(BLKTAP_DEFERRED, &tap->dev_inuse);
  37                 list_add_tail(&tap->deferred_queue, &deferred_work_queue);
  38         }
  39         spin_unlock_irqrestore(&deferred_work_lock, flags);
  40 }