From 287922eb0b186e2a5bf54fdd04b734c25c90035c Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Fri, 30 Oct 2015 20:57:30 +0800 Subject: block: defer timeouts to a workqueue Timer context is not very useful for drivers to perform any meaningful abort action from. So instead of calling the driver from this useless context defer it to a workqueue as soon as possible. Note that while a delayed_work item would seem the right thing here I didn't dare to use it due to the magic in blk_add_timer that pokes deep into timer internals. But maybe this encourages Tejun to add a sensible API for that to the workqueue API and we'll all be fine in the end :) Contains a major update from Keith Bush: "This patch removes synchronizing the timeout work so that the timer can start a freeze on its own queue. The timer enters the queue, so timer context can only start a freeze, but not wait for frozen." Signed-off-by: Christoph Hellwig Acked-by: Keith Busch Signed-off-by: Jens Axboe --- block/blk-mq.c | 11 ++++++++--- 1 file changed, 8 insertions(+), 3 deletions(-) (limited to 'block/blk-mq.c') diff --git a/block/blk-mq.c b/block/blk-mq.c index 93a4e1956915..9cb2894840ab 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -615,15 +615,19 @@ static void blk_mq_check_expired(struct blk_mq_hw_ctx *hctx, } } -static void blk_mq_rq_timer(unsigned long priv) +static void blk_mq_timeout_work(struct work_struct *work) { - struct request_queue *q = (struct request_queue *)priv; + struct request_queue *q = + container_of(work, struct request_queue, timeout_work); struct blk_mq_timeout_data data = { .next = 0, .next_set = 0, }; int i; + if (blk_queue_enter(q, true)) + return; + blk_mq_queue_tag_busy_iter(q, blk_mq_check_expired, &data); if (data.next_set) { @@ -638,6 +642,7 @@ static void blk_mq_rq_timer(unsigned long priv) blk_mq_tag_idle(hctx); } } + blk_queue_exit(q); } /* @@ -2015,7 +2020,7 @@ struct request_queue *blk_mq_init_allocated_queue(struct blk_mq_tag_set *set, hctxs[i]->queue_num = i; } - setup_timer(&q->timeout, blk_mq_rq_timer, (unsigned long) q); + INIT_WORK(&q->timeout_work, blk_mq_timeout_work); blk_queue_rq_timeout(q, set->timeout ? set->timeout : 30 * HZ); q->nr_queues = nr_cpu_ids; -- cgit v1.2.3 From bbc758ec04c2f30805ce0fcdfbaa4c3445fafbae Mon Sep 17 00:00:00 2001 From: Christoph Hellwig Date: Sat, 7 Nov 2015 09:39:28 +0100 Subject: block: remove REQ_NO_TIMEOUT flag This was added for the 'magic' AEN requests in the NVMe driver that never return. We now handle them purely inside the driver and don't need this core hack any more. Signed-off-by: Christoph Hellwig Acked-by: Keith Busch Signed-off-by: Jens Axboe --- block/blk-mq.c | 2 -- block/blk-timeout.c | 3 --- include/linux/blk_types.h | 2 -- 3 files changed, 7 deletions(-) (limited to 'block/blk-mq.c') diff --git a/block/blk-mq.c b/block/blk-mq.c index 9cb2894840ab..8f812b486c07 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -603,8 +603,6 @@ static void blk_mq_check_expired(struct blk_mq_hw_ctx *hctx, blk_mq_complete_request(rq, -EIO); return; } - if (rq->cmd_flags & REQ_NO_TIMEOUT) - return; if (time_after_eq(jiffies, rq->deadline)) { if (!blk_mark_rq_complete(rq)) diff --git a/block/blk-timeout.c b/block/blk-timeout.c index dd4fdfbcb3dd..a30441a200c0 100644 --- a/block/blk-timeout.c +++ b/block/blk-timeout.c @@ -197,9 +197,6 @@ void blk_add_timer(struct request *req) struct request_queue *q = req->q; unsigned long expiry; - if (req->cmd_flags & REQ_NO_TIMEOUT) - return; - /* blk-mq has its own handler, so we don't need ->rq_timed_out_fn */ if (!q->mq_ops && !q->rq_timed_out_fn) return; diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index 0fb65843ec1e..86a38ea1823f 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -188,7 +188,6 @@ enum rq_flag_bits { __REQ_PM, /* runtime pm request */ __REQ_HASHED, /* on IO scheduler merge hash */ __REQ_MQ_INFLIGHT, /* track inflight for MQ */ - __REQ_NO_TIMEOUT, /* requests may never expire */ __REQ_NR_BITS, /* stops here */ }; @@ -242,7 +241,6 @@ enum rq_flag_bits { #define REQ_PM (1ULL << __REQ_PM) #define REQ_HASHED (1ULL << __REQ_HASHED) #define REQ_MQ_INFLIGHT (1ULL << __REQ_MQ_INFLIGHT) -#define REQ_NO_TIMEOUT (1ULL << __REQ_NO_TIMEOUT) typedef unsigned int blk_qc_t; #define BLK_QC_T_NONE -1U -- cgit v1.2.3