From 7c94e1c157a227837b04f02f5edeff8301410ba2 Mon Sep 17 00:00:00 2001 From: Ming Lei Date: Thu, 25 Sep 2014 23:23:43 +0800 Subject: [PATCH] block: introduce blk_flush_queue to drive flush machinery This patch introduces 'struct blk_flush_queue' and puts all flush machinery related fields into this structure, so that - flush implementation details aren't exposed to driver - it is easy to convert to per dispatch-queue flush machinery This patch is basically a mechanical replacement. Reviewed-by: Christoph Hellwig Signed-off-by: Ming Lei Signed-off-by: Jens Axboe --- block/blk-core.c | 4 +- block/blk-flush.c | 111 +++++++++++++++++++++++++---------------- block/blk-mq.c | 10 ++-- block/blk.h | 22 +++++++- include/linux/blkdev.h | 10 +--- 5 files changed, 100 insertions(+), 57 deletions(-) diff --git a/block/blk-core.c b/block/blk-core.c index 222fe84d6ac4..cfaca8ca6cc4 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -390,11 +390,13 @@ static void __blk_drain_queue(struct request_queue *q, bool drain_all) * be drained. Check all the queues and counters. */ if (drain_all) { + struct blk_flush_queue *fq = blk_get_flush_queue(q); drain |= !list_empty(&q->queue_head); for (i = 0; i < 2; i++) { drain |= q->nr_rqs[i]; drain |= q->in_flight[i]; - drain |= !list_empty(&q->flush_queue[i]); + if (fq) + drain |= !list_empty(&fq->flush_queue[i]); } } diff --git a/block/blk-flush.c b/block/blk-flush.c index caf44756d329..b01a86d6bf86 100644 --- a/block/blk-flush.c +++ b/block/blk-flush.c @@ -28,7 +28,7 @@ * * The actual execution of flush is double buffered. Whenever a request * needs to execute PRE or POSTFLUSH, it queues at - * q->flush_queue[q->flush_pending_idx]. Once certain criteria are met, a + * fq->flush_queue[fq->flush_pending_idx]. Once certain criteria are met, a * flush is issued and the pending_idx is toggled. When the flush * completes, all the requests which were pending are proceeded to the next * step. This allows arbitrary merging of different types of FLUSH/FUA @@ -155,7 +155,7 @@ static bool blk_flush_queue_rq(struct request *rq, bool add_front) * completion and trigger the next step. * * CONTEXT: - * spin_lock_irq(q->queue_lock or q->mq_flush_lock) + * spin_lock_irq(q->queue_lock or fq->mq_flush_lock) * * RETURNS: * %true if requests were added to the dispatch queue, %false otherwise. @@ -164,7 +164,8 @@ static bool blk_flush_complete_seq(struct request *rq, unsigned int seq, int error) { struct request_queue *q = rq->q; - struct list_head *pending = &q->flush_queue[q->flush_pending_idx]; + struct blk_flush_queue *fq = blk_get_flush_queue(q); + struct list_head *pending = &fq->flush_queue[fq->flush_pending_idx]; bool queued = false, kicked; BUG_ON(rq->flush.seq & seq); @@ -180,12 +181,12 @@ static bool blk_flush_complete_seq(struct request *rq, unsigned int seq, case REQ_FSEQ_POSTFLUSH: /* queue for flush */ if (list_empty(pending)) - q->flush_pending_since = jiffies; + fq->flush_pending_since = jiffies; list_move_tail(&rq->flush.list, pending); break; case REQ_FSEQ_DATA: - list_move_tail(&rq->flush.list, &q->flush_data_in_flight); + list_move_tail(&rq->flush.list, &fq->flush_data_in_flight); queued = blk_flush_queue_rq(rq, true); break; @@ -220,17 +221,18 @@ static void flush_end_io(struct request *flush_rq, int error) bool queued = false; struct request *rq, *n; unsigned long flags = 0; + struct blk_flush_queue *fq = blk_get_flush_queue(q); if (q->mq_ops) { - spin_lock_irqsave(&q->mq_flush_lock, flags); + spin_lock_irqsave(&fq->mq_flush_lock, flags); flush_rq->tag = -1; } - running = &q->flush_queue[q->flush_running_idx]; - BUG_ON(q->flush_pending_idx == q->flush_running_idx); + running = &fq->flush_queue[fq->flush_running_idx]; + BUG_ON(fq->flush_pending_idx == fq->flush_running_idx); /* account completion of the flush request */ - q->flush_running_idx ^= 1; + fq->flush_running_idx ^= 1; if (!q->mq_ops) elv_completed_request(q, flush_rq); @@ -254,13 +256,13 @@ static void flush_end_io(struct request *flush_rq, int error) * directly into request_fn may confuse the driver. Always use * kblockd. */ - if (queued || q->flush_queue_delayed) { + if (queued || fq->flush_queue_delayed) { WARN_ON(q->mq_ops); blk_run_queue_async(q); } - q->flush_queue_delayed = 0; + fq->flush_queue_delayed = 0; if (q->mq_ops) - spin_unlock_irqrestore(&q->mq_flush_lock, flags); + spin_unlock_irqrestore(&fq->mq_flush_lock, flags); } /** @@ -271,33 +273,34 @@ static void flush_end_io(struct request *flush_rq, int error) * Please read the comment at the top of this file for more info. * * CONTEXT: - * spin_lock_irq(q->queue_lock or q->mq_flush_lock) + * spin_lock_irq(q->queue_lock or fq->mq_flush_lock) * * RETURNS: * %true if flush was issued, %false otherwise. */ static bool blk_kick_flush(struct request_queue *q) { - struct list_head *pending = &q->flush_queue[q->flush_pending_idx]; + struct blk_flush_queue *fq = blk_get_flush_queue(q); + struct list_head *pending = &fq->flush_queue[fq->flush_pending_idx]; struct request *first_rq = list_first_entry(pending, struct request, flush.list); - struct request *flush_rq = q->flush_rq; + struct request *flush_rq = fq->flush_rq; /* C1 described at the top of this file */ - if (q->flush_pending_idx != q->flush_running_idx || list_empty(pending)) + if (fq->flush_pending_idx != fq->flush_running_idx || list_empty(pending)) return false; /* C2 and C3 */ - if (!list_empty(&q->flush_data_in_flight) && + if (!list_empty(&fq->flush_data_in_flight) && time_before(jiffies, - q->flush_pending_since + FLUSH_PENDING_TIMEOUT)) + fq->flush_pending_since + FLUSH_PENDING_TIMEOUT)) return false; /* * Issue flush and toggle pending_idx. This makes pending_idx * different from running_idx, which means flush is in flight. */ - q->flush_pending_idx ^= 1; + fq->flush_pending_idx ^= 1; blk_rq_init(q, flush_rq); if (q->mq_ops) @@ -329,6 +332,7 @@ static void mq_flush_data_end_io(struct request *rq, int error) struct blk_mq_hw_ctx *hctx; struct blk_mq_ctx *ctx; unsigned long flags; + struct blk_flush_queue *fq = blk_get_flush_queue(q); ctx = rq->mq_ctx; hctx = q->mq_ops->map_queue(q, ctx->cpu); @@ -337,10 +341,10 @@ static void mq_flush_data_end_io(struct request *rq, int error) * After populating an empty queue, kick it to avoid stall. Read * the comment in flush_end_io(). */ - spin_lock_irqsave(&q->mq_flush_lock, flags); + spin_lock_irqsave(&fq->mq_flush_lock, flags); if (blk_flush_complete_seq(rq, REQ_FSEQ_DATA, error)) blk_mq_run_hw_queue(hctx, true); - spin_unlock_irqrestore(&q->mq_flush_lock, flags); + spin_unlock_irqrestore(&fq->mq_flush_lock, flags); } /** @@ -408,11 +412,13 @@ void blk_insert_flush(struct request *rq) rq->cmd_flags |= REQ_FLUSH_SEQ; rq->flush.saved_end_io = rq->end_io; /* Usually NULL */ if (q->mq_ops) { + struct blk_flush_queue *fq = blk_get_flush_queue(q); + rq->end_io = mq_flush_data_end_io; - spin_lock_irq(&q->mq_flush_lock); + spin_lock_irq(&fq->mq_flush_lock); blk_flush_complete_seq(rq, REQ_FSEQ_ACTIONS & ~policy, 0); - spin_unlock_irq(&q->mq_flush_lock); + spin_unlock_irq(&fq->mq_flush_lock); return; } rq->end_io = flush_data_end_io; @@ -473,31 +479,52 @@ int blkdev_issue_flush(struct block_device *bdev, gfp_t gfp_mask, } EXPORT_SYMBOL(blkdev_issue_flush); -static int blk_mq_init_flush(struct request_queue *q) +static struct blk_flush_queue *blk_alloc_flush_queue( + struct request_queue *q) { - struct blk_mq_tag_set *set = q->tag_set; + struct blk_flush_queue *fq; + int rq_sz = sizeof(struct request); - spin_lock_init(&q->mq_flush_lock); + fq = kzalloc(sizeof(*fq), GFP_KERNEL); + if (!fq) + goto fail; - q->flush_rq = kzalloc(round_up(sizeof(struct request) + - set->cmd_size, cache_line_size()), - GFP_KERNEL); - if (!q->flush_rq) - return -ENOMEM; - return 0; + if (q->mq_ops) { + spin_lock_init(&fq->mq_flush_lock); + rq_sz = round_up(rq_sz + q->tag_set->cmd_size, + cache_line_size()); + } + + fq->flush_rq = kzalloc(rq_sz, GFP_KERNEL); + if (!fq->flush_rq) + goto fail_rq; + + INIT_LIST_HEAD(&fq->flush_queue[0]); + INIT_LIST_HEAD(&fq->flush_queue[1]); + INIT_LIST_HEAD(&fq->flush_data_in_flight); + + return fq; + + fail_rq: + kfree(fq); + fail: + return NULL; +} + +static void blk_free_flush_queue(struct blk_flush_queue *fq) +{ + /* bio based request queue hasn't flush queue */ + if (!fq) + return; + + kfree(fq->flush_rq); + kfree(fq); } int blk_init_flush(struct request_queue *q) { - INIT_LIST_HEAD(&q->flush_queue[0]); - INIT_LIST_HEAD(&q->flush_queue[1]); - INIT_LIST_HEAD(&q->flush_data_in_flight); - - if (q->mq_ops) - return blk_mq_init_flush(q); - - q->flush_rq = kzalloc(sizeof(struct request), GFP_KERNEL); - if (!q->flush_rq) + q->fq = blk_alloc_flush_queue(q); + if (!q->fq) return -ENOMEM; return 0; @@ -505,5 +532,5 @@ int blk_init_flush(struct request_queue *q) void blk_exit_flush(struct request_queue *q) { - kfree(q->flush_rq); + blk_free_flush_queue(q->fq); } diff --git a/block/blk-mq.c b/block/blk-mq.c index 2758cdf2de94..d39e8a5eaeaa 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -508,20 +508,22 @@ void blk_mq_kick_requeue_list(struct request_queue *q) } EXPORT_SYMBOL(blk_mq_kick_requeue_list); -static inline bool is_flush_request(struct request *rq, unsigned int tag) +static inline bool is_flush_request(struct request *rq, + struct blk_flush_queue *fq, unsigned int tag) { return ((rq->cmd_flags & REQ_FLUSH_SEQ) && - rq->q->flush_rq->tag == tag); + fq->flush_rq->tag == tag); } struct request *blk_mq_tag_to_rq(struct blk_mq_tags *tags, unsigned int tag) { struct request *rq = tags->rqs[tag]; + struct blk_flush_queue *fq = blk_get_flush_queue(rq->q); - if (!is_flush_request(rq, tag)) + if (!is_flush_request(rq, fq, tag)) return rq; - return rq->q->flush_rq; + return fq->flush_rq; } EXPORT_SYMBOL(blk_mq_tag_to_rq); diff --git a/block/blk.h b/block/blk.h index c6fa3d4c6a89..833c4ac6c4eb 100644 --- a/block/blk.h +++ b/block/blk.h @@ -12,11 +12,28 @@ /* Max future timer expiry for timeouts */ #define BLK_MAX_TIMEOUT (5 * HZ) +struct blk_flush_queue { + unsigned int flush_queue_delayed:1; + unsigned int flush_pending_idx:1; + unsigned int flush_running_idx:1; + unsigned long flush_pending_since; + struct list_head flush_queue[2]; + struct list_head flush_data_in_flight; + struct request *flush_rq; + spinlock_t mq_flush_lock; +}; + extern struct kmem_cache *blk_requestq_cachep; extern struct kmem_cache *request_cachep; extern struct kobj_type blk_queue_ktype; extern struct ida blk_queue_ida; +static inline struct blk_flush_queue *blk_get_flush_queue( + struct request_queue *q) +{ + return q->fq; +} + static inline void __blk_get_queue(struct request_queue *q) { kobject_get(&q->kobj); @@ -89,6 +106,7 @@ void blk_insert_flush(struct request *rq); static inline struct request *__elv_next_request(struct request_queue *q) { struct request *rq; + struct blk_flush_queue *fq = blk_get_flush_queue(q); while (1) { if (!list_empty(&q->queue_head)) { @@ -111,9 +129,9 @@ static inline struct request *__elv_next_request(struct request_queue *q) * should be restarted later. Please see flush_end_io() for * details. */ - if (q->flush_pending_idx != q->flush_running_idx && + if (fq->flush_pending_idx != fq->flush_running_idx && !queue_flush_queueable(q)) { - q->flush_queue_delayed = 1; + fq->flush_queue_delayed = 1; return NULL; } if (unlikely(blk_queue_bypass(q)) || diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h index e267bf0db559..49f3461e4272 100644 --- a/include/linux/blkdev.h +++ b/include/linux/blkdev.h @@ -36,6 +36,7 @@ struct request; struct sg_io_hdr; struct bsg_job; struct blkcg_gq; +struct blk_flush_queue; #define BLKDEV_MIN_RQ 4 #define BLKDEV_MAX_RQ 128 /* Default maximum */ @@ -455,14 +456,7 @@ struct request_queue { */ unsigned int flush_flags; unsigned int flush_not_queueable:1; - unsigned int flush_queue_delayed:1; - unsigned int flush_pending_idx:1; - unsigned int flush_running_idx:1; - unsigned long flush_pending_since; - struct list_head flush_queue[2]; - struct list_head flush_data_in_flight; - struct request *flush_rq; - spinlock_t mq_flush_lock; + struct blk_flush_queue *fq; struct list_head requeue_list; spinlock_t requeue_lock;