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authorTejun Heo <tj@kernel.org>2011-12-15 20:03:04 +0100
committerJens Axboe <axboe@kernel.dk>2011-12-15 20:03:04 +0100
commit4eabc941259f9d8c8fb71746d3f30c87e1d9e49b (patch)
treef8ac1b8c1c1dc4d08830d2c430bef090b45dc277
parentb302545744c031eae04a43fb1c56cc17e00a193a (diff)
downloadlinux-linaro-stable-4eabc941259f9d8c8fb71746d3f30c87e1d9e49b.tar.gz
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: [<ffffffff81039a6a>] warn_slowpath_common+0x7a/0xb0 [<ffffffff81039b41>] warn_slowpath_fmt+0x41/0x50 [<ffffffff813d657f>] do_fd_request+0xbf/0xd0 [<ffffffff81322b95>] blk_drain_queue+0x65/0x80 [<ffffffff81322c93>] blk_cleanup_queue+0xe3/0x1a0 [<ffffffff818a809d>] floppy_init+0xdeb/0xe28 [<ffffffff818a72b2>] ? daring+0x6b/0x6b [<ffffffff810002af>] do_one_initcall+0x3f/0x170 [<ffffffff81884b34>] kernel_init+0x9d/0x11e [<ffffffff810317c2>] ? schedule_tail+0x22/0xa0 [<ffffffff815dbb14>] kernel_thread_helper+0x4/0x10 [<ffffffff81884a97>] ? start_kernel+0x2be/0x2be [<ffffffff815dbb10>] ? 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 <tj@kernel.org> Reported-by: Ralf Hildebrandt <Ralf.Hildebrandt@charite.de> Reported-by: Wu Fengguang <fengguang.wu@intel.com> Tested-by: Sergei Trofimovich <slyich@gmail.com> Signed-off-by: Jens Axboe <axboe@kernel.dk>
-rw-r--r--block/blk-core.c9
1 files changed, 8 insertions, 1 deletions
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];