block, cfq: fix empty queue crash caused by request merge
authorShaohua Li <shaohua.li@intel.com>
Fri, 16 Dec 2011 13:04:23 +0000 (14:04 +0100)
committerJens Axboe <axboe@kernel.dk>
Fri, 16 Dec 2011 13:04:23 +0000 (14:04 +0100)
commit6ae0516b8a50ece5d766be608a305707e0450060
tree90e4768d9d984d94cb45464b49b9c62b93ffba9f
parent4eabc941259f9d8c8fb71746d3f30c87e1d9e49b
block, cfq: fix empty queue crash caused by request merge

All requests of a queue could be merged to other requests of other queue.
Such queue will not have request in it, but it's in service tree. This
will cause kernel oops.
I encounter a BUG_ON() in cfq_dispatch_request() with next patch, but the
issue should exist without the patch.

Signed-off-by: Shaohua Li <shaohua.li@intel.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
block/cfq-iosched.c