dm suspend: return -ERESTARTSYS instead of -EINTR

This commit changes device mapper, so that it returns -ERESTARTSYS
instead of -EINTR when it is interrupted by a signal (so that the ioctl
can be restarted).

The manpage signal(7) says that the ioctl function should be restarted if
the signal was handled with SA_RESTART.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Cc: stable@vger.kernel.org

drivers/md/dm.c

@@ -2737,7 +2737,7 @@ static int dm_wait_for_bios_completion(struct mapped_device *md, unsigned int ta
 			break;
 
 		if (signal_pending_state(task_state, current)) {
-			r = -EINTR;
+			r = -ERESTARTSYS;
 			break;
 		}
 
@@ -2762,7 +2762,7 @@ static int dm_wait_for_completion(struct mapped_device *md, unsigned int task_st
 			break;
 
 		if (signal_pending_state(task_state, current)) {
-			r = -EINTR;
+			r = -ERESTARTSYS;
 			break;
 		}