From 43a5e4e21964a6efb4d14a34644ec7109d0ae891 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Thu, 26 Dec 2013 21:31:35 +0800 Subject: [PATCH] block: blk-mq: support draining mq queue blk_mq_drain_queue() is introduced so that we can drain mq queue inside blk_cleanup_queue(). Also don't accept new requests any more if queue is marked as dying. Cc: Jens Axboe Signed-off-by: Ming Lei Signed-off-by: Jens Axboe --- block/blk-core.c | 10 ++++++++-- block/blk-exec.c | 4 ++++ block/blk-mq.c | 43 +++++++++++++++++++++++++++---------------- block/blk-mq.h | 1 + 4 files changed, 40 insertions(+), 18 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index 5da8e900d3b1..accb7fc6ec94 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -38,6 +38,7 @@ #include "blk.h" #include "blk-cgroup.h" +#include "blk-mq.h" EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap); EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap); @@ -497,8 +498,13 @@ void blk_cleanup_queue(struct request_queue *q) * Drain all requests queued before DYING marking. Set DEAD flag to * prevent that q->request_fn() gets invoked after draining finished. */ - spin_lock_irq(lock); - __blk_drain_queue(q, true); + if (q->mq_ops) { + blk_mq_drain_queue(q); + spin_lock_irq(lock); + } else { + spin_lock_irq(lock); + __blk_drain_queue(q, true); + } queue_flag_set(QUEUE_FLAG_DEAD, q); spin_unlock_irq(lock); diff --git a/block/blk-exec.c b/block/blk-exec.c index c3edf9dff566..bbfc072a79c2 100644 --- a/block/blk-exec.c +++ b/block/blk-exec.c @@ -60,6 +60,10 @@ void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk, rq->rq_disk = bd_disk; rq->end_io = done; + /* + * don't check dying flag for MQ because the request won't + * be resued after dying flag is set + */ if (q->mq_ops) { blk_mq_insert_request(q, rq, true); return; diff --git a/block/blk-mq.c b/block/blk-mq.c index 3929f43d0b03..e2f811cba417 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -106,10 +106,13 @@ static int blk_mq_queue_enter(struct request_queue *q) spin_lock_irq(q->queue_lock); ret = wait_event_interruptible_lock_irq(q->mq_freeze_wq, - !blk_queue_bypass(q), *q->queue_lock); + !blk_queue_bypass(q) || blk_queue_dying(q), + *q->queue_lock); /* inc usage with lock hold to avoid freeze_queue runs here */ - if (!ret) + if (!ret && !blk_queue_dying(q)) __percpu_counter_add(&q->mq_usage_counter, 1, 1000000); + else if (blk_queue_dying(q)) + ret = -ENODEV; spin_unlock_irq(q->queue_lock); return ret; @@ -120,6 +123,22 @@ static void blk_mq_queue_exit(struct request_queue *q) __percpu_counter_add(&q->mq_usage_counter, -1, 1000000); } +static void __blk_mq_drain_queue(struct request_queue *q) +{ + while (true) { + s64 count; + + spin_lock_irq(q->queue_lock); + count = percpu_counter_sum(&q->mq_usage_counter); + spin_unlock_irq(q->queue_lock); + + if (count == 0) + break; + blk_mq_run_queues(q, false); + msleep(10); + } +} + /* * Guarantee no request is in use, so we can change any data structure of * the queue afterward. @@ -133,21 +152,13 @@ static void blk_mq_freeze_queue(struct request_queue *q) queue_flag_set(QUEUE_FLAG_BYPASS, q); spin_unlock_irq(q->queue_lock); - if (!drain) - return; + if (drain) + __blk_mq_drain_queue(q); +} - while (true) { - s64 count; - - spin_lock_irq(q->queue_lock); - count = percpu_counter_sum(&q->mq_usage_counter); - spin_unlock_irq(q->queue_lock); - - if (count == 0) - break; - blk_mq_run_queues(q, false); - msleep(10); - } +void blk_mq_drain_queue(struct request_queue *q) +{ + __blk_mq_drain_queue(q); } static void blk_mq_unfreeze_queue(struct request_queue *q) diff --git a/block/blk-mq.h b/block/blk-mq.h index 52bf1f96a2c2..caa614f24409 100644 --- a/block/blk-mq.h +++ b/block/blk-mq.h @@ -27,6 +27,7 @@ void blk_mq_complete_request(struct request *rq, int error); void blk_mq_run_request(struct request *rq, bool run_queue, bool async); void blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async); void blk_mq_init_flush(struct request_queue *q); +void blk_mq_drain_queue(struct request_queue *q); /* * CPU hotplug helpers