| Message ID | 20170925202924.16603-3-bart.vanassche@wdc.com (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
On 09/25/2017 10:29 PM, Bart Van Assche wrote: > From: Ming Lei <ming.lei@redhat.com> > > This patch makes it possible to pause request allocation for > the legacy block layer by calling blk_mq_freeze_queue() and > blk_mq_unfreeze_queue(). > > Signed-off-by: Ming Lei <ming.lei@redhat.com> > [ bvanassche: Combined two patches into one, edited a comment and made sure > REQ_NOWAIT is handled properly in blk_old_get_request() ] > Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> > Cc: Ming Lei <ming.lei@redhat.com> > Cc: Christoph Hellwig <hch@lst.de> > Cc: Hannes Reinecke <hare@suse.com> > Cc: Johannes Thumshirn <jthumshirn@suse.de> > --- > block/blk-core.c | 12 ++++++++++++ > block/blk-mq.c | 10 ++-------- > 2 files changed, 14 insertions(+), 8 deletions(-) > I actually had a customer reoport hitting a q_usage_counter underflow, so this is a real bugfix. And I'd advocate to have it pushed independently on the overall patchset, if it should be delayed even further. Reviewed-by: Hannes Reinecke <hare@suse.com> Cheers, Hannes
On Mon, Sep 25, 2017 at 01:29:19PM -0700, Bart Van Assche wrote: > From: Ming Lei <ming.lei@redhat.com> > > This patch makes it possible to pause request allocation for > the legacy block layer by calling blk_mq_freeze_queue() and > blk_mq_unfreeze_queue(). > > Signed-off-by: Ming Lei <ming.lei@redhat.com> > [ bvanassche: Combined two patches into one, edited a comment and made sure > REQ_NOWAIT is handled properly in blk_old_get_request() ] > Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com> > Cc: Ming Lei <ming.lei@redhat.com> > Cc: Christoph Hellwig <hch@lst.de> > Cc: Hannes Reinecke <hare@suse.com> > Cc: Johannes Thumshirn <jthumshirn@suse.de> > --- Thanks for considering block legacy path in this version!
Looks fine,
Reviewed-by: Christoph Hellwig <hch@lst.de>
diff --git a/block/blk-core.c b/block/blk-core.c index aebe676225e6..fef7133f8b0e 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -610,6 +610,9 @@ void blk_set_queue_dying(struct request_queue *q) } spin_unlock_irq(q->queue_lock); } + + /* Make blk_queue_enter() reexamine the DYING flag. */ + wake_up_all(&q->mq_freeze_wq); } EXPORT_SYMBOL_GPL(blk_set_queue_dying); @@ -1392,16 +1395,22 @@ static struct request *blk_old_get_request(struct request_queue *q, unsigned int op, gfp_t gfp_mask) { struct request *rq; + int ret = 0; WARN_ON_ONCE(q->mq_ops); /* create ioc upfront */ create_io_context(gfp_mask, q->node); + ret = blk_queue_enter(q, !(gfp_mask & __GFP_DIRECT_RECLAIM) || + (op & REQ_NOWAIT)); + if (ret) + return ERR_PTR(ret); spin_lock_irq(q->queue_lock); rq = get_request(q, op, NULL, gfp_mask); if (IS_ERR(rq)) { spin_unlock_irq(q->queue_lock); + blk_queue_exit(q); return rq; } @@ -1573,6 +1582,7 @@ void __blk_put_request(struct request_queue *q, struct request *req) blk_free_request(rl, req); freed_request(rl, sync, rq_flags); blk_put_rl(rl); + blk_queue_exit(q); } } EXPORT_SYMBOL_GPL(__blk_put_request); @@ -1854,8 +1864,10 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio) * Grab a free request. This is might sleep but can not fail. * Returns with the queue unlocked. */ + blk_queue_enter_live(q); req = get_request(q, bio->bi_opf, bio, GFP_NOIO); if (IS_ERR(req)) { + blk_queue_exit(q); __wbt_done(q->rq_wb, wb_acct); if (PTR_ERR(req) == -ENOMEM) bio->bi_status = BLK_STS_RESOURCE; diff --git a/block/blk-mq.c b/block/blk-mq.c index 98a18609755e..10c1f49f663d 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -125,7 +125,8 @@ void blk_freeze_queue_start(struct request_queue *q) freeze_depth = atomic_inc_return(&q->mq_freeze_depth); if (freeze_depth == 1) { percpu_ref_kill(&q->q_usage_counter); - blk_mq_run_hw_queues(q, false); + if (q->mq_ops) + blk_mq_run_hw_queues(q, false); } } EXPORT_SYMBOL_GPL(blk_freeze_queue_start); @@ -255,13 +256,6 @@ void blk_mq_wake_waiters(struct request_queue *q) queue_for_each_hw_ctx(q, hctx, i) if (blk_mq_hw_queue_mapped(hctx)) blk_mq_tag_wakeup_all(hctx->tags, true); - - /* - * If we are called because the queue has now been marked as - * dying, we need to ensure that processes currently waiting on - * the queue are notified as well. - */ - wake_up_all(&q->mq_freeze_wq); } bool blk_mq_can_queue(struct blk_mq_hw_ctx *hctx)