Patch "nbd: ratelimit error msgs after socket close" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

nbd: ratelimit error msgs after socket close

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
nbd-ratelimit-error-msgs-after-socket-close.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Dan Streetman <[email protected]>
Date: Thu, 14 Jan 2016 13:42:32 -0500
Subject: nbd: ratelimit error msgs after socket close

From: Dan Streetman <[email protected]>

commit da6ccaaa79caca4f38b540b651238f87215217a2 upstream.

Make the "Attempted send on closed socket" error messages generated in nbd_request_handler() ratelimited.

When the nbd socket is shutdown, the nbd_request_handler() function emits an error message for every request remaining in its queue. If the queue is large, this will spam a large amount of messages to the log. There's no need for a separate error message for each request, so this patch ratelimits it.

In the specific case this was found, the system was virtual and the error messages were logged to the serial port, which overwhelmed it.

---
 drivers/block/nbd.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

@@ -618,8 +618,8 @@ static void nbd_request_handler(struct r
 			req, req->cmd_type);
 
 		if (unlikely(!nbd->sock)) {
-			dev_err(disk_to_dev(nbd->disk),
-				"Attempted send on closed socket\n");
+			dev_err_ratelimited(disk_to_dev(nbd->disk),
+					    "Attempted send on closed socket\n");
 			req->errors++;
 			nbd_end_request(nbd, req);
 			spin_lock_irq(q->queue_lock);

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/nbd-ratelimit-error-msgs-after-socket-close.patch