[PATCH] CFQ: use irq safe locking in cfq_cic_link()

If cfq_set_request() is called for a new process AND a non-fs io
request (so that __GFP_WAIT may not be set), cfq_cic_link() may
use spin_lock_irq() and spin_unlock_irq() with interrupts already
disabled.

Fix is to always use irq safe locking in cfq_cic_link()

Acked-By: Arjan van de Ven <arjan@linux.intel.com>
Acked-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index d3d76136f53a..5c3da894a56c 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -1362,6 +1362,7 @@ cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc,
         struct rb_node **p;
         struct rb_node *parent;
         struct cfq_io_context *__cic;
+        unsigned long flags;
         void *k;
 
         cic->ioc = ioc;
@@ -1391,9 +1392,9 @@ restart:
         rb_link_node(&cic->rb_node, parent, p);
         rb_insert_color(&cic->rb_node, &ioc->cic_root);
 
-        spin_lock_irq(cfqd->queue->queue_lock);
+        spin_lock_irqsave(cfqd->queue->queue_lock, flags);
         list_add(&cic->queue_list, &cfqd->cic_list);
-        spin_unlock_irq(cfqd->queue->queue_lock);
+        spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
 }
 
 /*