[PATCH 04/10] block: use queue_limits_commit_update in queue_attr_store

[Christoph Hellwig]

Use queue_limits_commit_update to apply a consistent freeze vs limits
lock order in queue_attr_store.  Also remove taking the sysfs lock
as it doesn't protect anything here.

Signed-off-by: Christoph Hellwig <hch at lst.de>
---
 block/blk-sysfs.c | 18 ++++++++++--------
 1 file changed, 10 insertions(+), 8 deletions(-)

diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c
index 8d69315e986d..3bac27fcd635 100644
--- a/block/blk-sysfs.c
+++ b/block/blk-sysfs.c
@@ -687,22 +687,24 @@ queue_attr_store(struct kobject *kobj, struct attribute *attr,
 	if (entry->load_module)
 		entry->load_module(disk, page, length);
 
-	mutex_lock(&q->sysfs_lock);
-	blk_mq_freeze_queue(q);
 	if (entry->store_limit) {
 		struct queue_limits lim = queue_limits_start_update(q);
 
 		res = entry->store_limit(disk, page, length, &lim);
 		if (res < 0) {
 			queue_limits_cancel_update(q);
-		} else {
-			res = queue_limits_commit_update(q, &lim);
-			if (!res)
-				res = length;
+			return res;
 		}
-	} else {
-		res = entry->store(disk, page, length);
+
+		res = queue_limits_commit_update_frozen(q, &lim);
+		if (res)
+			return res;
+		return length;
 	}
+
+	mutex_lock(&q->sysfs_lock);
+	blk_mq_freeze_queue(q);
+	res = entry->store(disk, page, length);
 	blk_mq_unfreeze_queue(q);
 	mutex_unlock(&q->sysfs_lock);
 	return res;
-- 
2.45.2