Add wait_for_completion_killable

Signed-off-by: NMatthew Wilcox <willy@linux.intel.com>

include/linux/completion.h

@@ -44,6 +44,7 @@ static inline void init_completion(struct completion *x)
 
 extern void wait_for_completion(struct completion *);
 extern int wait_for_completion_interruptible(struct completion *x);
+extern int wait_for_completion_killable(struct completion *x);
 extern unsigned long wait_for_completion_timeout(struct completion *x,
 						   unsigned long timeout);
 extern unsigned long wait_for_completion_interruptible_timeout(

kernel/sched.c

@@ -3881,8 +3881,10 @@ do_wait_for_common(struct completion *x, long timeout, int state)
 		wait.flags |= WQ_FLAG_EXCLUSIVE;
 		__add_wait_queue_tail(&x->wait, &wait);
 		do {
-			if (state == TASK_INTERRUPTIBLE &&
-			    signal_pending(current)) {
+			if ((state == TASK_INTERRUPTIBLE &&
+			     signal_pending(current)) ||
+			    (state == TASK_KILLABLE &&
+			     fatal_signal_pending(current))) {
 				__remove_wait_queue(&x->wait, &wait);
 				return -ERESTARTSYS;
 			}
@@ -3942,6 +3944,15 @@ wait_for_completion_interruptible_timeout(struct completion *x,
 }
 EXPORT_SYMBOL(wait_for_completion_interruptible_timeout);
 
+int __sched wait_for_completion_killable(struct completion *x)
+{
+	long t = wait_for_common(x, MAX_SCHEDULE_TIMEOUT, TASK_KILLABLE);
+	if (t == -ERESTARTSYS)
+		return t;
+	return 0;
+}
+EXPORT_SYMBOL(wait_for_completion_killable);
+
 static long __sched
 sleep_on_common(wait_queue_head_t *q, int state, long timeout)
 {