Merge tag 'for-5.18/block-2022-04-01' of git://git.kernel.dk/linux-block

Pull block fixes from Jens Axboe:
 "Either fixes or a few additions that got missed in the initial merge
  window pull. In detail:

   - List iterator fix to avoid leaking value post loop (Jakob)

   - One-off fix in minor count (Christophe)

   - Fix for a regression in how io priority setting works for an
     exiting task (Jiri)

   - Fix a regression in this merge window with blkg_free() being called
     in an inappropriate context (Ming)

   - Misc fixes (Ming, Tom)"

* tag 'for-5.18/block-2022-04-01' of git://git.kernel.dk/linux-block:
  blk-wbt: remove wbt_track stub
  block: use dedicated list iterator variable
  block: Fix the maximum minor value is blk_alloc_ext_minor()
  block: restore the old set_task_ioprio() behaviour wrt PF_EXITING
  block: avoid calling blkg_free() in atomic context
  lib/sbitmap: allocate sb->map via kvzalloc_node

1 files changed, 22 insertions, 10 deletions

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 0430926426fe..8dfe62786cd5 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -65,19 +65,12 @@ static bool blkcg_policy_enabled(struct request_queue *q,
 	return pol && test_bit(pol->plid, q->blkcg_pols);
 }
 
-/**
- * blkg_free - free a blkg
- * @blkg: blkg to free
- *
- * Free @blkg which may be partially allocated.
- */
-static void blkg_free(struct blkcg_gq *blkg)
+static void blkg_free_workfn(struct work_struct *work)
 {
+	struct blkcg_gq *blkg = container_of(work, struct blkcg_gq,
+					     free_work);
 	int i;
 
-	if (!blkg)
-		return;
-
 	for (i = 0; i < BLKCG_MAX_POLS; i++)
 		if (blkg->pd[i])
 			blkcg_policy[i]->pd_free_fn(blkg->pd[i]);
@@ -89,6 +82,25 @@ static void blkg_free(struct blkcg_gq *blkg)
 	kfree(blkg);
 }
 
+/**
+ * blkg_free - free a blkg
+ * @blkg: blkg to free
+ *
+ * Free @blkg which may be partially allocated.
+ */
+static void blkg_free(struct blkcg_gq *blkg)
+{
+	if (!blkg)
+		return;
+
+	/*
+	 * Both ->pd_free_fn() and request queue's release handler may
+	 * sleep, so free us by scheduling one work func
+	 */
+	INIT_WORK(&blkg->free_work, blkg_free_workfn);
+	schedule_work(&blkg->free_work);
+}
+
 static void __blkg_release(struct rcu_head *rcu)
 {
 	struct blkcg_gq *blkg = container_of(rcu, struct blkcg_gq, rcu_head);