Messages in this thread Patch in this message | | | From | Tejun Heo <> | Subject | [PATCH 01/36] block: blk-throttle should be drained regardless of q->elevator | Date | Tue, 21 Feb 2012 17:46:28 -0800 |
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Currently, blk_cleanup_queue() doesn't call elv_drain_elevator() if q->elevator doesn't exist; however, bio based drivers don't have elevator initialized but can still use blk-throttle. This patch moves q->elevator test inside blk_drain_queue() such that only elv_drain_elevator() is skipped if !q->elevator.
-v2: loop can have registered queue which has NULL request_fn. Make sure we don't call into __blk_run_queue() in such cases.
Signed-off-by: Tejun Heo <tj@kernel.org> Reported-by: Vivek Goyal <vgoyal@redhat.com> --- block/blk-core.c | 26 ++++++++++++++------------ 1 files changed, 14 insertions(+), 12 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c index 3a78b00..7752ec2 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -365,17 +365,24 @@ void blk_drain_queue(struct request_queue *q, bool drain_all) spin_lock_irq(q->queue_lock); - elv_drain_elevator(q); + /* + * The caller might be trying to drain @q before its + * elevator is initialized. + */ + if (q->elevator) + elv_drain_elevator(q); + if (drain_all) blk_throtl_drain(q); /* * This function might be called on a queue which failed - * driver init after queue creation. Some drivers - * (e.g. fd) get unhappy in such cases. Kick queue iff - * dispatch queue has something on it. + * driver init after queue creation or is not yet fully + * active yet. Some drivers (e.g. fd and loop) get unhappy + * in such cases. Kick queue iff dispatch queue has + * something on it and @q has request_fn set. */ - if (!list_empty(&q->queue_head)) + if (!list_empty(&q->queue_head) && q->request_fn) __blk_run_queue(q); drain |= q->rq.elvpriv; @@ -428,13 +435,8 @@ void blk_cleanup_queue(struct request_queue *q) spin_unlock_irq(lock); mutex_unlock(&q->sysfs_lock); - /* - * Drain all requests queued before DEAD marking. The caller might - * be trying to tear down @q before its elevator is initialized, in - * which case we don't want to call into draining. - */ - if (q->elevator) - blk_drain_queue(q, true); + /* drain all requests queued before DEAD marking */ + blk_drain_queue(q, true); /* @q won't process any more request, flush async actions */ del_timer_sync(&q->backing_dev_info.laptop_mode_wb_timer); -- 1.7.7.3
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