From 332ebbf7f9efb31ffc363b99da548963ee3fd66d Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Tue, 20 Jun 2017 11:15:46 -0700 Subject: [PATCH] block: Document what queue type each function is intended for Some functions in block/blk-core.c must only be used on blk-sq queues while others are safe to use against any queue type. Document which functions are intended for blk-sq queues and issue a warning if the blk-sq API is misused. This does not only help block driver authors but will also make it easier to remove the blk-sq code once that code is declared obsolete. Signed-off-by: Bart Van Assche Reviewed-by: Christoph Hellwig Cc: Hannes Reinecke Cc: Omar Sandoval Cc: Ming Lei Signed-off-by: Jens Axboe --- block/blk-core.c | 33 +++++++++++++++++++++++++++++++++ block/blk.h | 2 ++ 2 files changed, 35 insertions(+) diff --git a/block/blk-core.c b/block/blk-core.c index 5f87788249ce..2e02314ea331 100644 --- a/block/blk-core.c +++ b/block/blk-core.c @@ -241,6 +241,7 @@ static void blk_delay_work(struct work_struct *work) void blk_delay_queue(struct request_queue *q, unsigned long msecs) { lockdep_assert_held(q->queue_lock); + WARN_ON_ONCE(q->mq_ops); if (likely(!blk_queue_dead(q))) queue_delayed_work(kblockd_workqueue, &q->delay_work, @@ -260,6 +261,7 @@ EXPORT_SYMBOL(blk_delay_queue); void blk_start_queue_async(struct request_queue *q) { lockdep_assert_held(q->queue_lock); + WARN_ON_ONCE(q->mq_ops); queue_flag_clear(QUEUE_FLAG_STOPPED, q); blk_run_queue_async(q); @@ -279,6 +281,7 @@ void blk_start_queue(struct request_queue *q) { lockdep_assert_held(q->queue_lock); WARN_ON(!irqs_disabled()); + WARN_ON_ONCE(q->mq_ops); queue_flag_clear(QUEUE_FLAG_STOPPED, q); __blk_run_queue(q); @@ -302,6 +305,7 @@ EXPORT_SYMBOL(blk_start_queue); void blk_stop_queue(struct request_queue *q) { lockdep_assert_held(q->queue_lock); + WARN_ON_ONCE(q->mq_ops); cancel_delayed_work(&q->delay_work); queue_flag_set(QUEUE_FLAG_STOPPED, q); @@ -356,6 +360,7 @@ EXPORT_SYMBOL(blk_sync_queue); inline void __blk_run_queue_uncond(struct request_queue *q) { lockdep_assert_held(q->queue_lock); + WARN_ON_ONCE(q->mq_ops); if (unlikely(blk_queue_dead(q))) return; @@ -383,6 +388,7 @@ EXPORT_SYMBOL_GPL(__blk_run_queue_uncond); void __blk_run_queue(struct request_queue *q) { lockdep_assert_held(q->queue_lock); + WARN_ON_ONCE(q->mq_ops); if (unlikely(blk_queue_stopped(q))) return; @@ -407,6 +413,7 @@ EXPORT_SYMBOL(__blk_run_queue); void blk_run_queue_async(struct request_queue *q) { lockdep_assert_held(q->queue_lock); + WARN_ON_ONCE(q->mq_ops); if (likely(!blk_queue_stopped(q) && !blk_queue_dead(q))) mod_delayed_work(kblockd_workqueue, &q->delay_work, 0); @@ -425,6 +432,8 @@ void blk_run_queue(struct request_queue *q) { unsigned long flags; + WARN_ON_ONCE(q->mq_ops); + spin_lock_irqsave(q->queue_lock, flags); __blk_run_queue(q); spin_unlock_irqrestore(q->queue_lock, flags); @@ -453,6 +462,7 @@ static void __blk_drain_queue(struct request_queue *q, bool drain_all) int i; lockdep_assert_held(q->queue_lock); + WARN_ON_ONCE(q->mq_ops); while (true) { bool drain = false; @@ -531,6 +541,8 @@ static void __blk_drain_queue(struct request_queue *q, bool drain_all) */ void blk_queue_bypass_start(struct request_queue *q) { + WARN_ON_ONCE(q->mq_ops); + spin_lock_irq(q->queue_lock); q->bypass_depth++; queue_flag_set(QUEUE_FLAG_BYPASS, q); @@ -557,6 +569,9 @@ EXPORT_SYMBOL_GPL(blk_queue_bypass_start); * @q: queue of interest * * Leave bypass mode and restore the normal queueing behavior. + * + * Note: although blk_queue_bypass_start() is only called for blk-sq queues, + * this function is called for both blk-sq and blk-mq queues. */ void blk_queue_bypass_end(struct request_queue *q) { @@ -954,6 +969,8 @@ static blk_qc_t blk_queue_bio(struct request_queue *q, struct bio *bio); int blk_init_allocated_queue(struct request_queue *q) { + WARN_ON_ONCE(q->mq_ops); + q->fq = blk_alloc_flush_queue(q, NUMA_NO_NODE, q->cmd_size); if (!q->fq) return -ENOMEM; @@ -1091,6 +1108,8 @@ int blk_update_nr_requests(struct request_queue *q, unsigned int nr) struct request_list *rl; int on_thresh, off_thresh; + WARN_ON_ONCE(q->mq_ops); + spin_lock_irq(q->queue_lock); q->nr_requests = nr; blk_queue_congestion_threshold(q); @@ -1329,6 +1348,7 @@ static struct request *get_request(struct request_queue *q, unsigned int op, struct request *rq; lockdep_assert_held(q->queue_lock); + WARN_ON_ONCE(q->mq_ops); rl = blk_get_rl(q, bio); /* transferred to @rq on success */ retry: @@ -1373,6 +1393,8 @@ static struct request *blk_old_get_request(struct request_queue *q, { struct request *rq; + WARN_ON_ONCE(q->mq_ops); + /* create ioc upfront */ create_io_context(gfp_mask, q->node); @@ -1424,6 +1446,7 @@ EXPORT_SYMBOL(blk_get_request); void blk_requeue_request(struct request_queue *q, struct request *rq) { lockdep_assert_held(q->queue_lock); + WARN_ON_ONCE(q->mq_ops); blk_delete_timer(rq); blk_clear_rq_complete(rq); @@ -2495,6 +2518,7 @@ struct request *blk_peek_request(struct request_queue *q) int ret; lockdep_assert_held(q->queue_lock); + WARN_ON_ONCE(q->mq_ops); while ((rq = __elv_next_request(q)) != NULL) { @@ -2615,6 +2639,7 @@ void blk_dequeue_request(struct request *rq) void blk_start_request(struct request *req) { lockdep_assert_held(req->q->queue_lock); + WARN_ON_ONCE(req->q->mq_ops); blk_dequeue_request(req); @@ -2646,6 +2671,7 @@ struct request *blk_fetch_request(struct request_queue *q) struct request *rq; lockdep_assert_held(q->queue_lock); + WARN_ON_ONCE(q->mq_ops); rq = blk_peek_request(q); if (rq) @@ -2797,6 +2823,7 @@ void blk_finish_request(struct request *req, blk_status_t error) struct request_queue *q = req->q; lockdep_assert_held(req->q->queue_lock); + WARN_ON_ONCE(q->mq_ops); if (req->rq_flags & RQF_STATS) blk_stat_add(req); @@ -2851,6 +2878,8 @@ static bool blk_end_bidi_request(struct request *rq, blk_status_t error, struct request_queue *q = rq->q; unsigned long flags; + WARN_ON_ONCE(q->mq_ops); + if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes)) return true; @@ -2880,6 +2909,7 @@ static bool __blk_end_bidi_request(struct request *rq, blk_status_t error, unsigned int nr_bytes, unsigned int bidi_bytes) { lockdep_assert_held(rq->q->queue_lock); + WARN_ON_ONCE(rq->q->mq_ops); if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes)) return true; @@ -2906,6 +2936,7 @@ static bool __blk_end_bidi_request(struct request *rq, blk_status_t error, bool blk_end_request(struct request *rq, blk_status_t error, unsigned int nr_bytes) { + WARN_ON_ONCE(rq->q->mq_ops); return blk_end_bidi_request(rq, error, nr_bytes, 0); } EXPORT_SYMBOL(blk_end_request); @@ -2948,6 +2979,7 @@ bool __blk_end_request(struct request *rq, blk_status_t error, unsigned int nr_bytes) { lockdep_assert_held(rq->q->queue_lock); + WARN_ON_ONCE(rq->q->mq_ops); return __blk_end_bidi_request(rq, error, nr_bytes, 0); } @@ -2967,6 +2999,7 @@ void __blk_end_request_all(struct request *rq, blk_status_t error) unsigned int bidi_bytes = 0; lockdep_assert_held(rq->q->queue_lock); + WARN_ON_ONCE(rq->q->mq_ops); if (unlikely(blk_bidi_rq(rq))) bidi_bytes = blk_rq_bytes(rq->next_rq); diff --git a/block/blk.h b/block/blk.h index 83c8e1100525..798691a5e5e9 100644 --- a/block/blk.h +++ b/block/blk.h @@ -143,6 +143,8 @@ static inline struct request *__elv_next_request(struct request_queue *q) struct request *rq; struct blk_flush_queue *fq = blk_get_flush_queue(q, NULL); + WARN_ON_ONCE(q->mq_ops); + while (1) { if (!list_empty(&q->queue_head)) { rq = list_entry_rq(q->queue_head.next); -- 2.20.1