FAILED: patch "[PATCH] dm: fix ioctl retry termination with signal" failed to apply to 3.14-stable tree

The patch below does not apply to the 3.14-stable tree.
If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.

thanks,

greg k-h

------------------ original commit in Linus's tree ------------------

From: Junichi Nomura <[email protected]>
Date: Tue, 17 Nov 2015 09:39:26 +0000
Subject: [PATCH] dm: fix ioctl retry termination with signal

dm-mpath retries ioctl, when no path is readily available and the device is configured to queue I/O in such a case. If you want to stop the retry before multipathd decides to turn off queueing mode, you could send signal for the process to exit from the loop.

However the check of fatal signal has not carried along when commit 6c182cd88d17 ("dm mpath: fix ioctl deadlock when no paths") moved the loop from dm-mpath to dm core. As a result, we can't terminate such a process in the retry loop.

Easy reproducer of the situation is:

  # dmsetup create mp --table '0 1024 multipath 0 0 0 0'
  # dmsetup message mp 0 'queue_if_no_path'
  # sg_inq /dev/mapper/mp

then you should be able to terminate sg_inq by pressing Ctrl+C.

index aaa6caa46a9f..3d1829237678 100644
@@ -1562,7 +1562,7 @@ static int multipath_prepare_ioctl(struct dm_target *ti,
 
 	spin_unlock_irqrestore(&m->lock, flags);
 
-	if (r == -ENOTCONN && !fatal_signal_pending(current)) {
+	if (r == -ENOTCONN) {
 		spin_lock_irqsave(&m->lock, flags);
 		if (!m->current_pg) {
 			/* Path status changed, redo selection */

index 6e15f3565892..fabd5d8fd559 100644
@@ -591,7 +591,7 @@ retry:
 
 out:
 	dm_put_live_table(md, *srcu_idx);
-	if (r == -ENOTCONN) {
+	if (r == -ENOTCONN && !fatal_signal_pending(current)) {
 		msleep(10);
 		goto retry;
 	}