block: don't call ioc_exit_icq() with the queue lock held for blk-mq
authorJens Axboe <axboe@fb.com>
Thu, 2 Mar 2017 20:59:08 +0000 (13:59 -0700)
committerJens Axboe <axboe@fb.com>
Thu, 2 Mar 2017 20:59:08 +0000 (13:59 -0700)
commit7b36a7189fc320f0b783dd51bd1f541db56cfbdd
treec527bc3477255dfc0064390f2073533c6a652c2b
parenta5a79d00017c9eee68a9bcb40d5dfd6f45f17461
block: don't call ioc_exit_icq() with the queue lock held for blk-mq

For legacy scheduling, we always call ioc_exit_icq() with both the
ioc and queue lock held. This poses a problem for blk-mq with
scheduling, since the queue lock isn't what we use in the scheduler.
And since we don't need the queue lock held for ioc exit there,
don't grab it and leave any extra locking up to the blk-mq scheduler.

Reported-by: Paolo Valente <paolo.valente@linaro.org>
Tested-by: Paolo Valente <paolo.valente@linaro.org>
Reviewed-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
block/blk-ioc.c
block/blk-sysfs.c
block/elevator.c