]> git.baikalelectronics.ru Git - kernel.git/commit
virtio_blk: fix race between start and stop queue
authorMing Lei <tom.leiming@gmail.com>
Fri, 16 May 2014 15:31:21 +0000 (23:31 +0800)
committerJens Axboe <axboe@fb.com>
Tue, 27 May 2014 14:41:10 +0000 (08:41 -0600)
commitfdbf63cbe786b144b7b993b74ffa10a148aa0b16
tree1d0483a969d1f2c43cdd35547c9e1bc99df6b791
parent419a9346387238873fd9e69c819649a2befa7159
virtio_blk: fix race between start and stop queue

When there isn't enough vring descriptor for adding to vq,
blk-mq will be put as stopped state until some of pending
descriptors are completed & freed.

Unfortunately, the vq's interrupt may come just before
blk-mq's BLK_MQ_S_STOPPED flag is set, so the blk-mq will
still be kept as stopped even though lots of descriptors
are completed and freed in the interrupt handler. The worst
case is that all pending descriptors are freed in the
interrupt handler, and the queue is kept as stopped forever.

This patch fixes the problem by starting/stopping blk-mq
with holding vq_lock.

Cc: Jens Axboe <axboe@kernel.dk>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: Ming Lei <tom.leiming@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <axboe@fb.com>
Conflicts:
drivers/block/virtio_blk.c
drivers/block/virtio_blk.c