Merge tag 'block-5.7-2020-04-10' of git://git.kernel.dk/linux-block

Pull block fixes from Jens Axboe:
 "Here's a set of fixes that should go into this merge window. This
  contains:

   - NVMe pull request from Christoph with various fixes

   - Better discard support for loop (Evan)

   - Only call ->commit_rqs() if we have queued IO (Keith)

   - blkcg offlining fixes (Tejun)

   - fix (and fix the fix) for busy partitions"

* tag 'block-5.7-2020-04-10' of git://git.kernel.dk/linux-block:
  block: fix busy device checking in blk_drop_partitions again
  block: fix busy device checking in blk_drop_partitions
  nvmet-rdma: fix double free of rdma queue
  blk-mq: don't commit_rqs() if none were queued
  nvme-fc: Revert "add module to ops template to allow module references"
  nvme: fix deadlock caused by ANA update wrong locking
  nvmet-rdma: fix bonding failover possible NULL deref
  loop: Better discard support for block devices
  loop: Report EOPNOTSUPP properly
  nvmet: fix NULL dereference when removing a referral
  nvme: inherit stable pages constraint in the mpath stack device
  blkcg: don't offline parent blkcg first
  blkcg: rename blkcg->cgwb_refcnt to ->online_pin and always use it
  nvme-tcp: fix possible crash in recv error flow
  nvme-tcp: don't poll a non-live queue
  nvme-tcp: fix possible crash in write_zeroes processing
  nvmet-fc: fix typo in comment
  nvme-rdma: Replace comma with a semicolon
  nvme-fcloop: fix deallocation of working context
  nvme: fix compat address handling in several ioctls

3 files changed, 26 insertions, 7 deletions

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index c15a26096038..c5dc833212e1 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -883,8 +883,8 @@ static void blkcg_css_offline(struct cgroup_subsys_state *css)
 	/* this prevents anyone from attaching or migrating to this blkcg */
 	wb_blkcg_offline(blkcg);
 
-	/* put the base cgwb reference allowing step 2 to be triggered */
-	blkcg_cgwb_put(blkcg);
+	/* put the base online pin allowing step 2 to be triggered */
+	blkcg_unpin_online(blkcg);
 }
 
 /**
@@ -983,11 +983,11 @@ blkcg_css_alloc(struct cgroup_subsys_state *parent_css)
 	}
 
 	spin_lock_init(&blkcg->lock);
+	refcount_set(&blkcg->online_pin, 1);
 	INIT_RADIX_TREE(&blkcg->blkg_tree, GFP_NOWAIT | __GFP_NOWARN);
 	INIT_HLIST_HEAD(&blkcg->blkg_list);
 #ifdef CONFIG_CGROUP_WRITEBACK
 	INIT_LIST_HEAD(&blkcg->cgwb_list);
-	refcount_set(&blkcg->cgwb_refcnt, 1);
 #endif
 	list_add_tail(&blkcg->all_blkcgs_node, &all_blkcgs);
 
@@ -1006,6 +1006,21 @@ unlock:
 	return ret;
 }
 
+static int blkcg_css_online(struct cgroup_subsys_state *css)
+{
+	struct blkcg *blkcg = css_to_blkcg(css);
+	struct blkcg *parent = blkcg_parent(blkcg);
+
+	/*
+	 * blkcg_pin_online() is used to delay blkcg offline so that blkgs
+	 * don't go offline while cgwbs are still active on them.  Pin the
+	 * parent so that offline always happens towards the root.
+	 */
+	if (parent)
+		blkcg_pin_online(parent);
+	return 0;
+}
+
 /**
  * blkcg_init_queue - initialize blkcg part of request queue
  * @q: request_queue to initialize
@@ -1199,6 +1214,7 @@ static void blkcg_exit(struct task_struct *tsk)
 
 struct cgroup_subsys io_cgrp_subsys = {
 	.css_alloc = blkcg_css_alloc,
+	.css_online = blkcg_css_online,
 	.css_offline = blkcg_css_offline,
 	.css_free = blkcg_css_free,
 	.can_attach = blkcg_can_attach,
diff --git a/block/blk-mq.c b/block/blk-mq.c
index f6291ceedee4..8e56884fd2e9 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1289,7 +1289,7 @@ bool blk_mq_dispatch_rq_list(struct request_queue *q, struct list_head *list,
 		 * the driver there was more coming, but that turned out to
 		 * be a lie.
 		 */
-		if (q->mq_ops->commit_rqs)
+		if (q->mq_ops->commit_rqs && queued)
 			q->mq_ops->commit_rqs(hctx);
 
 		spin_lock(&hctx->lock);
@@ -1911,6 +1911,8 @@ blk_status_t blk_mq_request_issue_directly(struct request *rq, bool last)
 void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
 		struct list_head *list)
 {
+	int queued = 0;
+
 	while (!list_empty(list)) {
 		blk_status_t ret;
 		struct request *rq = list_first_entry(list, struct request,
@@ -1926,7 +1928,8 @@ void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
 				break;
 			}
 			blk_mq_end_request(rq, ret);
-		}
+		} else
+			queued++;
 	}
 
 	/*
@@ -1934,7 +1937,7 @@ void blk_mq_try_issue_list_directly(struct blk_mq_hw_ctx *hctx,
 	 * the driver there was more coming, but that turned out to
 	 * be a lie.
 	 */
-	if (!list_empty(list) && hctx->queue->mq_ops->commit_rqs)
+	if (!list_empty(list) && hctx->queue->mq_ops->commit_rqs && queued)
 		hctx->queue->mq_ops->commit_rqs(hctx);
 }
 
diff --git a/block/partitions/core.c b/block/partitions/core.c
index b79c4513629b..bc1ded1331b1 100644
--- a/block/partitions/core.c
+++ b/block/partitions/core.c
@@ -496,7 +496,7 @@ int blk_drop_partitions(struct gendisk *disk, struct block_device *bdev)
 
 	if (!disk_part_scan_enabled(disk))
 		return 0;
-	if (bdev->bd_part_count || bdev->bd_super)
+	if (bdev->bd_part_count || bdev->bd_openers > 1)
 		return -EBUSY;
 	res = invalidate_partition(disk, 0);
 	if (res)