[PATCH] blk_start_queue() must be called with irq disabled - add warning
The queue lock can be taken from interrupts so it must always be taken with
irq disabling primitives. Some primitives already verify this.
blk_start_queue() is called under this lock, so interrupts must be
disabled.
Also document this requirement clearly in blk_init_queue(), where the queue
spinlock is set.
Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Jens Axboe <axboe@suse.de>
diff --git a/block/ll_rw_blk.c b/block/ll_rw_blk.c
index 465b543..17c42dd 100644
--- a/block/ll_rw_blk.c
+++ b/block/ll_rw_blk.c
@@ -1663,6 +1663,8 @@
**/
void blk_start_queue(request_queue_t *q)
{
+ WARN_ON(!irqs_disabled());
+
clear_bit(QUEUE_FLAG_STOPPED, &q->queue_flags);
/*
@@ -1878,7 +1880,8 @@
* get dealt with eventually.
*
* The queue spin lock must be held while manipulating the requests on the
- * request queue.
+ * request queue; this lock will be taken also from interrupt context, so irq
+ * disabling is needed for it.
*
* Function returns a pointer to the initialized request queue, or NULL if
* it didn't succeed.