Commit 4ddd56b0 authored Aug 17, 2017 by Bart Van Assche Committed by Jens Axboe Aug 18, 2017

block: Relax a check in blk_start_queue()



Calling blk_start_queue() from interrupt context with the queue
lock held and without disabling IRQs, as the skd driver does, is
safe. This patch avoids that loading the skd driver triggers the
following warning:

WARNING: CPU: 11 PID: 1348 at block/blk-core.c:283 blk_start_queue+0x84/0xa0
RIP: 0010:blk_start_queue+0x84/0xa0
Call Trace:
 skd_unquiesce_dev+0x12a/0x1d0 [skd]
 skd_complete_internal+0x1e7/0x5a0 [skd]
 skd_complete_other+0xc2/0xd0 [skd]
 skd_isr_completion_posted.isra.30+0x2a5/0x470 [skd]
 skd_isr+0x14f/0x180 [skd]
 irq_forced_thread_fn+0x2a/0x70
 irq_thread+0x144/0x1a0
 kthread+0x125/0x140
 ret_from_fork+0x2a/0x40

Fixes: commit a038e253 ("[PATCH] blk_start_queue() must be called with irq disabled - add warning")
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>
Cc: Andrew Morton <akpm@osdl.org>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.de>
Cc: Johannes Thumshirn <jthumshirn@suse.de>
Cc: <stable@vger.kernel.org>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

parent ccc22257

block/blk-core.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -280,7 +280,7 @@ EXPORT_SYMBOL(blk_start_queue_async);
		void blk_start_queue(struct request_queue *q)
		{
		lockdep_assert_held(q->queue_lock);
		WARN_ON(!irqs_disabled());
		WARN_ON(!in_interrupt() && !irqs_disabled());
		WARN_ON_ONCE(q->mq_ops);

		queue_flag_clear(QUEUE_FLAG_STOPPED, q);

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