Merge branch 'for-linus' of git://git.kernel.dk/linux-block

Pull block fixes from Jens Axboe:
 "A collection of fixes since the merge window;

   - fix for a double elevator module release, from Chao Yu.  Ancient bug.

   - the splice() MORE flag fix from Christophe Leroy.

   - a fix for NVMe, fixing a patch that went in in the merge window.
     From Keith.

   - two fixes for blk-mq CPU hotplug handling, from Ming Lei.

   - bdi vs blockdev lifetime fix from Neil Brown, fixing and oops in md.

   - two blk-mq fixes from Shaohua, fixing a race on queue stop and a
     bad merge issue with FUA writes.

   - division-by-zero fix for writeback from Tejun.

   - a block bounce page accounting fix, making sure we inc/dec after
     bouncing so that pre/post IO pages match up.  From Wang YanQing"

* 'for-linus' of git://git.kernel.dk/linux-block:
  splice: sendfile() at once fails for big files
  blk-mq: don't lose requests if a stopped queue restarts
  blk-mq: fix FUA request hang
  block: destroy bdi before blockdev is unregistered.
  block:bounce: fix call inc_|dec_zone_page_state on different pages confuse value of NR_BOUNCE
  elevator: fix double release of elevator module
  writeback: use |1 instead of +1 to protect against div by zero
  blk-mq: fix CPU hotplug handling
  blk-mq: fix race between timeout and CPU hotplug
  NVMe: Fix VPD B0 max sectors translation

5 files changed, 40 insertions, 32 deletions

diff --git a/block/blk-core.c b/block/blk-core.c
index fd154b94447a..7871603f0a29 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -552,6 +552,8 @@ void blk_cleanup_queue(struct request_queue *q)
 		q->queue_lock = &q->__queue_lock;
 	spin_unlock_irq(lock);
 
+	bdi_destroy(&q->backing_dev_info);
+
 	/* @q is and will stay empty, shutdown and put */
 	blk_put_queue(q);
 }
diff --git a/block/blk-mq.c b/block/blk-mq.c
index ade8a2d1b0aa..e68b71b85a7e 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -677,8 +677,11 @@ static void blk_mq_rq_timer(unsigned long priv)
 		data.next = blk_rq_timeout(round_jiffies_up(data.next));
 		mod_timer(&q->timeout, data.next);
 	} else {
-		queue_for_each_hw_ctx(q, hctx, i)
-			blk_mq_tag_idle(hctx);
+		queue_for_each_hw_ctx(q, hctx, i) {
+			/* the hctx may be unmapped, so check it here */
+			if (blk_mq_hw_queue_mapped(hctx))
+				blk_mq_tag_idle(hctx);
+		}
 	}
 }
 
@@ -855,6 +858,16 @@ static void __blk_mq_run_hw_queue(struct blk_mq_hw_ctx *hctx)
 		spin_lock(&hctx->lock);
 		list_splice(&rq_list, &hctx->dispatch);
 		spin_unlock(&hctx->lock);
+		/*
+		 * the queue is expected stopped with BLK_MQ_RQ_QUEUE_BUSY, but
+		 * it's possible the queue is stopped and restarted again
+		 * before this. Queue restart will dispatch requests. And since
+		 * requests in rq_list aren't added into hctx->dispatch yet,
+		 * the requests in rq_list might get lost.
+		 *
+		 * blk_mq_run_hw_queue() already checks the STOPPED bit
+		 **/
+		blk_mq_run_hw_queue(hctx, true);
 	}
 }
 
@@ -1571,22 +1584,6 @@ static int blk_mq_hctx_cpu_offline(struct blk_mq_hw_ctx *hctx, int cpu)
 	return NOTIFY_OK;
 }
 
-static int blk_mq_hctx_cpu_online(struct blk_mq_hw_ctx *hctx, int cpu)
-{
-	struct request_queue *q = hctx->queue;
-	struct blk_mq_tag_set *set = q->tag_set;
-
-	if (set->tags[hctx->queue_num])
-		return NOTIFY_OK;
-
-	set->tags[hctx->queue_num] = blk_mq_init_rq_map(set, hctx->queue_num);
-	if (!set->tags[hctx->queue_num])
-		return NOTIFY_STOP;
-
-	hctx->tags = set->tags[hctx->queue_num];
-	return NOTIFY_OK;
-}
-
 static int blk_mq_hctx_notify(void *data, unsigned long action,
 			      unsigned int cpu)
 {
@@ -1594,8 +1591,11 @@ static int blk_mq_hctx_notify(void *data, unsigned long action,
 
 	if (action == CPU_DEAD || action == CPU_DEAD_FROZEN)
 		return blk_mq_hctx_cpu_offline(hctx, cpu);
-	else if (action == CPU_ONLINE || action == CPU_ONLINE_FROZEN)
-		return blk_mq_hctx_cpu_online(hctx, cpu);
+
+	/*
+	 * In case of CPU online, tags may be reallocated
+	 * in blk_mq_map_swqueue() after mapping is updated.
+	 */
 
 	return NOTIFY_OK;
 }
@@ -1775,6 +1775,7 @@ static void blk_mq_map_swqueue(struct request_queue *q)
 	unsigned int i;
 	struct blk_mq_hw_ctx *hctx;
 	struct blk_mq_ctx *ctx;
+	struct blk_mq_tag_set *set = q->tag_set;
 
 	queue_for_each_hw_ctx(q, hctx, i) {
 		cpumask_clear(hctx->cpumask);
@@ -1803,16 +1804,20 @@ static void blk_mq_map_swqueue(struct request_queue *q)
 		 * disable it and free the request entries.
 		 */
 		if (!hctx->nr_ctx) {
-			struct blk_mq_tag_set *set = q->tag_set;
-
 			if (set->tags[i]) {
 				blk_mq_free_rq_map(set, set->tags[i], i);
 				set->tags[i] = NULL;
-				hctx->tags = NULL;
 			}
+			hctx->tags = NULL;
 			continue;
 		}
 
+		/* unmapped hw queue can be remapped after CPU topo changed */
+		if (!set->tags[i])
+			set->tags[i] = blk_mq_init_rq_map(set, i);
+		hctx->tags = set->tags[i];
+		WARN_ON(!hctx->tags);
+
 		/*
 		 * Set the map size to the number of mapped software queues.
 		 * This is more accurate and more efficient than looping
@@ -2090,9 +2095,16 @@ static int blk_mq_queue_reinit_notify(struct notifier_block *nb,
 	 */
 	list_for_each_entry(q, &all_q_list, all_q_node)
 		blk_mq_freeze_queue_start(q);
-	list_for_each_entry(q, &all_q_list, all_q_node)
+	list_for_each_entry(q, &all_q_list, all_q_node) {
 		blk_mq_freeze_queue_wait(q);
 
+		/*
+		 * timeout handler can't touch hw queue during the
+		 * reinitialization
+		 */
+		del_timer_sync(&q->timeout);
+	}
+
 	list_for_each_entry(q, &all_q_list, all_q_node)
 		blk_mq_queue_reinit(q);
 
diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index faaf36ade7eb..2b8fd302f677 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -522,8 +522,6 @@ static void blk_release_queue(struct kobject *kobj)
 
 	blk_trace_shutdown(q);
 
-	bdi_destroy(&q->backing_dev_info);
-
 	ida_simple_remove(&blk_queue_ida, q->id);
 	call_rcu(&q->rcu_head, blk_free_queue_rcu);
 }
diff --git a/block/bounce.c b/block/bounce.c
index ab21ba203d5c..ed9dd8067120 100644
--- a/block/bounce.c
+++ b/block/bounce.c
@@ -221,8 +221,8 @@ bounce:
 		if (page_to_pfn(page) <= queue_bounce_pfn(q) && !force)
 			continue;
 
-		inc_zone_page_state(to->bv_page, NR_BOUNCE);
 		to->bv_page = mempool_alloc(pool, q->bounce_gfp);
+		inc_zone_page_state(to->bv_page, NR_BOUNCE);
 
 		if (rw == WRITE) {
 			char *vto, *vfrom;
diff --git a/block/elevator.c b/block/elevator.c
index 59794d0d38e3..8985038f398c 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -157,7 +157,7 @@ struct elevator_queue *elevator_alloc(struct request_queue *q,
 
 	eq = kzalloc_node(sizeof(*eq), GFP_KERNEL, q->node);
 	if (unlikely(!eq))
-		goto err;
+		return NULL;
 
 	eq->type = e;
 	kobject_init(&eq->kobj, &elv_ktype);
@@ -165,10 +165,6 @@ struct elevator_queue *elevator_alloc(struct request_queue *q,
 	hash_init(eq->hash);
 
 	return eq;
-err:
-	kfree(eq);
-	elevator_put(e);
-	return NULL;
 }
 EXPORT_SYMBOL(elevator_alloc);