Commit a038e253 authored Jun 05, 2006 by Paolo 'Blaisorblade' Giarrusso Committed by Jens Axboe Jun 23, 2006

[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>

parent bae386f7

block/ll_rw_blk.c

+4 −1

Original line number	Diff line number	Diff line
		@@ -1663,6 +1663,8 @@ static void blk_unplug_timeout(unsigned long data)
		**/
		void blk_start_queue(request_queue_t *q)
		{
		WARN_ON(!irqs_disabled());

		clear_bit(QUEUE_FLAG_STOPPED, &q->queue_flags);

		/*
		@@ -1878,7 +1880,8 @@ EXPORT_SYMBOL(blk_alloc_queue_node);
		* 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.