From: Hugh Dickins <hugh@veritas.com>
Date: Wed, 29 Jun 2005 14:15:40 +0000 (+0100)
Subject: [PATCH] Fix get_request nastiness
X-Git-Tag: v2.6.13-rc2~65
X-Git-Url: https://openfabrics.org/gitweb/?a=commitdiff_plain;h=fd782a4a99d2d3e818b9465c427b10f7f027d7da;p=~shefty%2Frdma-dev.git

[PATCH] Fix get_request nastiness

get_request is now expected to be holding on to queue_lock, with interrupts
disabled, when it returns NULL; but one path forgot that, causing all kinds
of nastiness under swap load - badness backtraces, strange failures, BUGs.

Signed-off-by: Hugh Dickins <hugh@veritas.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---

diff --git a/drivers/block/ll_rw_blk.c b/drivers/block/ll_rw_blk.c
index 1197462bb6b..692a5fced76 100644
--- a/drivers/block/ll_rw_blk.c
+++ b/drivers/block/ll_rw_blk.c
@@ -1917,10 +1917,9 @@ get_rq:
 	 * limit of requests, otherwise we could have thousands of requests
 	 * allocated with any setting of ->nr_requests
 	 */
-	if (rl->count[rw] >= (3 * q->nr_requests / 2)) {
-		spin_unlock_irq(q->queue_lock);
+	if (rl->count[rw] >= (3 * q->nr_requests / 2))
 		goto out;
-	}
+
 	rl->count[rw]++;
 	rl->starved[rw] = 0;
 	if (rl->count[rw] >= queue_congestion_on_threshold(q))