From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Date: Wed, 21 Jun 2017 09:46:34 +0800 From: Ming Lei To: Bart Van Assche Cc: Jens Axboe , linux-block@vger.kernel.org, Christoph Hellwig , Hannes Reinecke , "Martin K . Petersen" Subject: Re: [PATCH] blk-mq: Make it safe to call blk_mq_quiesce_queue_nowait() from an interrupt handler Message-ID: <20170621014633.GB8382@ming.t460p> References: <20170620164020.18260-1-bart.vanassche@wdc.com> <20170621014231.GA8382@ming.t460p> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii In-Reply-To: <20170621014231.GA8382@ming.t460p> List-ID: On Wed, Jun 21, 2017 at 09:42:36AM +0800, Ming Lei wrote: > On Tue, Jun 20, 2017 at 09:40:20AM -0700, Bart Van Assche wrote: > > Since blk_mq_quiesce_queue_nowait() can be called from interrupt > > context, make this safe. Since this function is not in the hot > > path, uninline it. Untested. > > > > Fixes: commit f4560ffe8cec ("blk-mq: use QUEUE_FLAG_QUIESCED to quiesce queue") > > Signed-off-by: Bart Van Assche > > Cc: Ming Lei > > Cc: Hannes Reinecke > > Cc: Martin K. Petersen > > --- > > block/blk-mq.c | 14 ++++++++++++++ > > include/linux/blk-mq.h | 10 +--------- > > 2 files changed, 15 insertions(+), 9 deletions(-) > > > > diff --git a/block/blk-mq.c b/block/blk-mq.c > > index 1c4f1f4978c6..92faf340dc92 100644 > > --- a/block/blk-mq.c > > +++ b/block/blk-mq.c > > @@ -153,6 +153,20 @@ void blk_mq_unfreeze_queue(struct request_queue *q) > > } > > EXPORT_SYMBOL_GPL(blk_mq_unfreeze_queue); > > > > +/* > > + * FIXME: replace the scsi_internal_device_*block_nowait() calls in the > > + * mpt3sas driver such that this function can be removed. > > + */ > > +void blk_mq_quiesce_queue_nowait(struct request_queue *q) > > +{ > > + unsigned long flags; > > + > > + spin_lock_irqsave(q->queue_lock, flags); > > + queue_flag_set(QUEUE_FLAG_QUIESCED, q); > > + spin_unlock_irqrestore(q->queue_lock, flags); > > +} > > +EXPORT_SYMBOL_GPL(blk_mq_quiesce_queue_nowait); > > + > > /** > > * blk_mq_quiesce_queue() - wait until all ongoing dispatches have finished > > * @q: request queue. > > diff --git a/include/linux/blk-mq.h b/include/linux/blk-mq.h > > index 366b83cee955..23d32ff0b462 100644 > > --- a/include/linux/blk-mq.h > > +++ b/include/linux/blk-mq.h > > @@ -266,15 +266,7 @@ int blk_mq_reinit_tagset(struct blk_mq_tag_set *set); > > int blk_mq_map_queues(struct blk_mq_tag_set *set); > > void blk_mq_update_nr_hw_queues(struct blk_mq_tag_set *set, int nr_hw_queues); > > > > -/* > > - * FIXME: this helper is just for working around mpt3sas. > > - */ > > -static inline void blk_mq_quiesce_queue_nowait(struct request_queue *q) > > -{ > > - spin_lock_irq(q->queue_lock); > > - queue_flag_set(QUEUE_FLAG_QUIESCED, q); > > - spin_unlock_irq(q->queue_lock); > > -} > > +void blk_mq_quiesce_queue_nowait(struct request_queue *q); > > > > /* > > * Driver command data is immediately after the request. So subtract request > > -- > > 2.13.1 > > > > Looks fine, > > Reviewed-by: Ming Lei Also we should save/restore irq flags in blk_mq_unquiesce_queue() since scsi_start_queue() does that too, could you fix the two in this patch? Thanks, Ming