diff options
| author | Omar Sandoval <osandov@fb.com> | 2017-02-10 10:32:34 -0800 |
|---|---|---|
| committer | Jens Axboe <axboe@fb.com> | 2017-02-10 11:34:47 -0700 |
| commit | 3d492c2e0146ccaad08c7cbe16e2e229328b5e79 (patch) | |
| tree | c78b95cdedb006cdc11a99e6a0e253f8875cee11 /block | |
| parent | f6f94300cda0f85180a0dd8838d1cc855661e239 (diff) | |
| download | linux-3d492c2e0146ccaad08c7cbe16e2e229328b5e79.tar.gz linux-3d492c2e0146ccaad08c7cbe16e2e229328b5e79.tar.bz2 linux-3d492c2e0146ccaad08c7cbe16e2e229328b5e79.zip | |
blk-mq-sched: don't hold queue_lock when calling exit_icq
None of the other blk-mq elevator hooks are called with this lock held.
Additionally, it can lead to circular locking dependencies between
queue_lock and the private scheduler lock.
Reported-by: Paolo Valente <paolo.valente@linaro.org>
Signed-off-by: Omar Sandoval <osandov@fb.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-ioc.c | 22 |
1 files changed, 16 insertions, 6 deletions
diff --git a/block/blk-ioc.c b/block/blk-ioc.c index fe186a9eade9..b12f9c87b4c3 100644 --- a/block/blk-ioc.c +++ b/block/blk-ioc.c @@ -35,7 +35,10 @@ static void icq_free_icq_rcu(struct rcu_head *head) kmem_cache_free(icq->__rcu_icq_cache, icq); } -/* Exit an icq. Called with both ioc and q locked. */ +/* + * Exit an icq. Called with both ioc and q locked for sq, only ioc locked for + * mq. + */ static void ioc_exit_icq(struct io_cq *icq) { struct elevator_type *et = icq->q->elevator->type; @@ -166,6 +169,7 @@ EXPORT_SYMBOL(put_io_context); */ void put_io_context_active(struct io_context *ioc) { + struct elevator_type *et; unsigned long flags; struct io_cq *icq; @@ -184,13 +188,19 @@ retry: hlist_for_each_entry(icq, &ioc->icq_list, ioc_node) { if (icq->flags & ICQ_EXITED) continue; - if (spin_trylock(icq->q->queue_lock)) { + + et = icq->q->elevator->type; + if (et->uses_mq) { ioc_exit_icq(icq); - spin_unlock(icq->q->queue_lock); } else { - spin_unlock_irqrestore(&ioc->lock, flags); - cpu_relax(); - goto retry; + if (spin_trylock(icq->q->queue_lock)) { + ioc_exit_icq(icq); + spin_unlock(icq->q->queue_lock); + } else { + spin_unlock_irqrestore(&ioc->lock, flags); + cpu_relax(); + goto retry; + } } } spin_unlock_irqrestore(&ioc->lock, flags); |