From: Jens Axboe Date: Mon, 30 Oct 2006 18:54:23 +0000 (+0100) Subject: [PATCH] CFQ: bad locking in changed_ioprio() X-Git-Tag: v2.6.19-rc4~20 X-Git-Url: https://err.no/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c1b707d253fe918b92882cff1dbd926b47e14fd2;p=linux-2.6 [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 Signed-off-by: Linus Torvalds --- diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c index 5c3da894a5..25c4e7ed0d 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)