From c1b707d253fe918b92882cff1dbd926b47e14fd2 Mon Sep 17 00:00:00 2001
From: Jens Axboe <jens.axboe@oracle.com>
Date: Mon, 30 Oct 2006 19:54:23 +0100
Subject: [PATCH] [PATCH] CFQ: bad locking in changed_ioprio()
When the ioprio code recently got juggled a bit, a bug was introduced.
changed_ioprio() is no longer called with interrupts disabled, so using
plain spin_lock() on the queue_lock is a bug.
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
---
block/cfq-iosched.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 5c3da894a56c8..25c4e7ed0d00f 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1215,11 +1215,12 @@ static inline void changed_ioprio(struct cfq_io_context *cic)
{
struct cfq_data *cfqd = cic->key;
struct cfq_queue *cfqq;
+ unsigned long flags;
if (unlikely(!cfqd))
return;
- spin_lock(cfqd->queue->queue_lock);
+ spin_lock_irqsave(cfqd->queue->queue_lock, flags);
cfqq = cic->cfqq[ASYNC];
if (cfqq) {
@@ -1236,7 +1237,7 @@ static inline void changed_ioprio(struct cfq_io_context *cic)
if (cfqq)
cfq_mark_cfqq_prio_changed(cfqq);
- spin_unlock(cfqd->queue->queue_lock);
+ spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
}
static void cfq_ioc_set_ioprio(struct io_context *ioc)
--
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