diff options
| author | Ming Lei <ming.lei@redhat.com> | 2018-01-06 16:27:38 +0800 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2018-01-06 09:25:36 -0700 |
| commit | 24f5a90f0d13a97b51aa79f468143fafea4246bb (patch) | |
| tree | 4fe0235db1e0e32b1945933df172ca91456ced78 /block | |
| parent | c2856ae2f315d754a0b6a268e4c6745b332b42e7 (diff) | |
blk-mq: quiesce queue during switching io sched and updating nr_requests
Dispatch may still be in-progress after queue is frozen, so we have to
quiesce queue before switching IO scheduler and updating nr_requests.
Also when switching io schedulers, blk_mq_run_hw_queue() may still be
called somewhere(such as from nvme_reset_work()), and io scheduler's
per-hctx data may not be setup yet, so cause oops even inside
blk_mq_hctx_has_pending(), such as it can be run just between:
ret = e->ops.mq.init_sched(q, e);
AND
ret = e->ops.mq.init_hctx(hctx, i)
inside blk_mq_init_sched().
This reverts commit 7a148c2fcff8330(block: don't call blk_mq_quiesce_queue()
after queue is frozen) basically, and makes sure blk_mq_hctx_has_pending
won't be called if queue is quiesced.
Reviewed-by: Christoph Hellwig <hch@lst.de>
Fixes: 7a148c2fcff83309(block: don't call blk_mq_quiesce_queue() after queue is frozen)
Reported-by: Yi Zhang <yi.zhang@redhat.com>
Tested-by: Yi Zhang <yi.zhang@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-mq.c | 27 | ||||
| -rw-r--r-- | block/elevator.c | 2 |
2 files changed, 28 insertions, 1 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c index 11097477eeab..1c66c319325c 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1285,7 +1285,30 @@ EXPORT_SYMBOL(blk_mq_delay_run_hw_queue); bool blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async) { - if (blk_mq_hctx_has_pending(hctx)) { + int srcu_idx; + bool need_run; + + /* + * When queue is quiesced, we may be switching io scheduler, or + * updating nr_hw_queues, or other things, and we can't run queue + * any more, even __blk_mq_hctx_has_pending() can't be called safely. + * + * And queue will be rerun in blk_mq_unquiesce_queue() if it is + * quiesced. + */ + if (!(hctx->flags & BLK_MQ_F_BLOCKING)) { + rcu_read_lock(); + need_run = !blk_queue_quiesced(hctx->queue) && + blk_mq_hctx_has_pending(hctx); + rcu_read_unlock(); + } else { + srcu_idx = srcu_read_lock(hctx->queue_rq_srcu); + need_run = !blk_queue_quiesced(hctx->queue) && + blk_mq_hctx_has_pending(hctx); + srcu_read_unlock(hctx->queue_rq_srcu, srcu_idx); + } + + if (need_run) { __blk_mq_delay_run_hw_queue(hctx, async, 0); return true; } @@ -2710,6 +2733,7 @@ int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr) return -EINVAL; blk_mq_freeze_queue(q); + blk_mq_quiesce_queue(q); ret = 0; queue_for_each_hw_ctx(q, hctx, i) { @@ -2733,6 +2757,7 @@ int blk_mq_update_nr_requests(struct request_queue *q, unsigned int nr) if (!ret) q->nr_requests = nr; + blk_mq_unquiesce_queue(q); blk_mq_unfreeze_queue(q); return ret; diff --git a/block/elevator.c b/block/elevator.c index 7bda083d5968..138faeb08a7c 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -968,6 +968,7 @@ static int elevator_switch_mq(struct request_queue *q, int ret; blk_mq_freeze_queue(q); + blk_mq_quiesce_queue(q); if (q->elevator) { if (q->elevator->registered) @@ -994,6 +995,7 @@ static int elevator_switch_mq(struct request_queue *q, blk_add_trace_msg(q, "elv switch: none"); out: + blk_mq_unquiesce_queue(q); blk_mq_unfreeze_queue(q); return ret; } |