From 4eabc941259f9d8c8fb71746d3f30c87e1d9e49b Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 15 Dec 2011 20:03:04 +0100 Subject: [PATCH] block: don't kick empty queue in blk_drain_queue() While probing, fd sets up queue, probes hardware and tears down the queue if probing fails. In the process, blk_drain_queue() kicks the queue which failed to finish initialization and fd is unhappy about that. floppy0: no floppy controllers found ------------[ cut here ]------------ WARNING: at drivers/block/floppy.c:2929 do_fd_request+0xbf/0xd0() Hardware name: To Be Filled By O.E.M. VFS: do_fd_request called on non-open device Modules linked in: Pid: 1, comm: swapper Not tainted 3.2.0-rc4-00077-g5983fe2 #2 Call Trace: [] warn_slowpath_common+0x7a/0xb0 [] warn_slowpath_fmt+0x41/0x50 [] do_fd_request+0xbf/0xd0 [] blk_drain_queue+0x65/0x80 [] blk_cleanup_queue+0xe3/0x1a0 [] floppy_init+0xdeb/0xe28 [] ? daring+0x6b/0x6b [] do_one_initcall+0x3f/0x170 [] kernel_init+0x9d/0x11e [] ? schedule_tail+0x22/0xa0 [] kernel_thread_helper+0x4/0x10 [] ? start_kernel+0x2be/0x2be [] ? gs_change+0xb/0xb Avoid it by making blk_drain_queue() kick queue iff dispatch queue has something on it. Signed-off-by: Tejun Heo Reported-by: Ralf Hildebrandt Reported-by: Wu Fengguang Tested-by: Sergei Trofimovich Signed-off-by: Jens Axboe --- block/blk-core.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/block/blk-core.c b/block/blk-core.c index 20d69f6beb6b..15de223c7f93 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -366,7 +366,14 @@ void blk_drain_queue(struct request_queue *q, bool drain_all) if (drain_all) blk_throtl_drain(q); - __blk_run_queue(q); + /* + * This function might be called on a queue which failed + * driver init after queue creation. Some drivers + * (e.g. fd) get unhappy in such cases. Kick queue iff + * dispatch queue has something on it. + */ + if (!list_empty(&q->queue_head)) + __blk_run_queue(q); if (drain_all) nr_rqs = q->rq.count[0] + q->rq.count[1]; -- 2.30.2