blk-mq: cleanup unused methods: blk_mq_hw_sysfs_store

We found that the blk_mq_hw_sysfs_store interface has no place to use.
The object default_hw_ctx_attrs using blk_mq_hw_sysfs_ops only uses
the show method and does not use the store method.

Since this patch:
4a46f05e ("blk-mq: move hctx and ctx counters from sysfs to debugfs")
moved the store method to debugfs, the store method is not used anymore.

So let me do some tiny work to clean up unused code.
Signed-off-by: Zhong Jinghua <zhongjinghua@huawei.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Link: https://lore.kernel.org/r/20230128030419.2780298-1-zhongjinghua@huawei.comSigned-off-by: Jens Axboe <axboe@kernel.dk>

block/blk-mq-sysfs.c

@@ -46,7 +46,6 @@ static void blk_mq_hw_sysfs_release(struct kobject *kobj)
 struct blk_mq_hw_ctx_sysfs_entry {
 	struct attribute attr;
 	ssize_t (*show)(struct blk_mq_hw_ctx *, char *);
-	ssize_t (*store)(struct blk_mq_hw_ctx *, const char *, size_t);
 };
 
 static ssize_t blk_mq_hw_sysfs_show(struct kobject *kobj,
@@ -70,28 +69,6 @@ static ssize_t blk_mq_hw_sysfs_show(struct kobject *kobj,
 	return res;
 }
 
-static ssize_t blk_mq_hw_sysfs_store(struct kobject *kobj,
-				     struct attribute *attr, const char *page,
-				     size_t length)
-{
-	struct blk_mq_hw_ctx_sysfs_entry *entry;
-	struct blk_mq_hw_ctx *hctx;
-	struct request_queue *q;
-	ssize_t res;
-
-	entry = container_of(attr, struct blk_mq_hw_ctx_sysfs_entry, attr);
-	hctx = container_of(kobj, struct blk_mq_hw_ctx, kobj);
-	q = hctx->queue;
-
-	if (!entry->store)
-		return -EIO;
-
-	mutex_lock(&q->sysfs_lock);
-	res = entry->store(hctx, page, length);
-	mutex_unlock(&q->sysfs_lock);
-	return res;
-}
-
 static ssize_t blk_mq_hw_sysfs_nr_tags_show(struct blk_mq_hw_ctx *hctx,
 					    char *page)
 {
@@ -150,7 +127,6 @@ ATTRIBUTE_GROUPS(default_hw_ctx);
 
 static const struct sysfs_ops blk_mq_hw_sysfs_ops = {
 	.show	= blk_mq_hw_sysfs_show,
-	.store	= blk_mq_hw_sysfs_store,
 };
 
 static struct kobj_type blk_mq_ktype = {