Merge tag 'block-5.14-2021-07-30' of git://git.kernel.dk/linux-block

Pull block fixes from Jens Axboe:

 - gendisk freeing fix (Christoph)

 - blk-iocost wake ordering fix (Tejun)

 - tag allocation error handling fix (John)

 - loop locking fix. While this isn't the prettiest fix in the world,
   nobody has any good alternatives for 5.14. Something to likely
   revisit for 5.15. (Tetsuo)

* tag 'block-5.14-2021-07-30' of git://git.kernel.dk/linux-block:
  block: delay freeing the gendisk
  blk-iocost: fix operation ordering in iocg_wake_fn()
  blk-mq-sched: Fix blk_mq_sched_alloc_tags() error handling
  loop: reintroduce global lock for safe loop_validate_file() traversal

3 files changed, 11 insertions, 20 deletions

diff --git a/block/blk-iocost.c b/block/blk-iocost.c
index c2d6bc88d3f1..5fac3757e6e0 100644
--- a/block/blk-iocost.c
+++ b/block/blk-iocost.c
@@ -1440,16 +1440,17 @@ static int iocg_wake_fn(struct wait_queue_entry *wq_entry, unsigned mode,
 		return -1;
 
 	iocg_commit_bio(ctx->iocg, wait->bio, wait->abs_cost, cost);
+	wait->committed = true;
 
 	/*
 	 * autoremove_wake_function() removes the wait entry only when it
-	 * actually changed the task state.  We want the wait always
-	 * removed.  Remove explicitly and use default_wake_function().
+	 * actually changed the task state. We want the wait always removed.
+	 * Remove explicitly and use default_wake_function(). Note that the
+	 * order of operations is important as finish_wait() tests whether
+	 * @wq_entry is removed without grabbing the lock.
 	 */
-	list_del_init(&wq_entry->entry);
-	wait->committed = true;
-
 	default_wake_function(wq_entry, mode, flags, key);
+	list_del_init_careful(&wq_entry->entry);
 	return 0;
 }
 
diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c
index c838d81ac058..0f006cabfd91 100644
--- a/block/blk-mq-sched.c
+++ b/block/blk-mq-sched.c
@@ -515,17 +515,6 @@ void blk_mq_sched_insert_requests(struct blk_mq_hw_ctx *hctx,
 	percpu_ref_put(&q->q_usage_counter);
 }
 
-static void blk_mq_sched_free_tags(struct blk_mq_tag_set *set,
-				   struct blk_mq_hw_ctx *hctx,
-				   unsigned int hctx_idx)
-{
-	if (hctx->sched_tags) {
-		blk_mq_free_rqs(set, hctx->sched_tags, hctx_idx);
-		blk_mq_free_rq_map(hctx->sched_tags, set->flags);
-		hctx->sched_tags = NULL;
-	}
-}
-
 static int blk_mq_sched_alloc_tags(struct request_queue *q,
 				   struct blk_mq_hw_ctx *hctx,
 				   unsigned int hctx_idx)
@@ -539,8 +528,10 @@ static int blk_mq_sched_alloc_tags(struct request_queue *q,
 		return -ENOMEM;
 
 	ret = blk_mq_alloc_rqs(set, hctx->sched_tags, hctx_idx, q->nr_requests);
-	if (ret)
-		blk_mq_sched_free_tags(set, hctx, hctx_idx);
+	if (ret) {
+		blk_mq_free_rq_map(hctx->sched_tags, set->flags);
+		hctx->sched_tags = NULL;
+	}
 
 	return ret;
 }
diff --git a/block/genhd.c b/block/genhd.c
index af4d2ab4a633..298ee78c1bda 100644
--- a/block/genhd.c
+++ b/block/genhd.c
@@ -1079,10 +1079,9 @@ static void disk_release(struct device *dev)
 	disk_release_events(disk);
 	kfree(disk->random);
 	xa_destroy(&disk->part_tbl);
-	bdput(disk->part0);
 	if (test_bit(GD_QUEUE_REF, &disk->state) && disk->queue)
 		blk_put_queue(disk->queue);
-	kfree(disk);
+	bdput(disk->part0);	/* frees the disk */
 }
 struct class block_class = {
 	.name		= "block",