blk-mq: free hctx->cpumask in release handler of hctx's kobject

It is obviously that hctx->cpumask is per hctx, and both
share same lifetime, so this patch moves freeing of hctx->cpumask
into release handler of hctx's kobject.
Signed-off-by: NMing Lei <tom.leiming@gmail.com>
Tested-by: NPeter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: NJens Axboe <axboe@fb.com>

block/blk-mq-sysfs.c

@@ -21,6 +21,7 @@ static void blk_mq_hw_sysfs_release(struct kobject *kobj)
 {
 	struct blk_mq_hw_ctx *hctx = container_of(kobj, struct blk_mq_hw_ctx,
 						  kobj);
+	free_cpumask_var(hctx->cpumask);
 	kfree(hctx->ctxs);
 	kfree(hctx);
 }

block/blk-mq.c

@@ -1955,16 +1955,6 @@ static void blk_mq_exit_hw_queues(struct request_queue *q,
 	}
 }
 
-static void blk_mq_free_hw_queues(struct request_queue *q,
-		struct blk_mq_tag_set *set)
-{
-	struct blk_mq_hw_ctx *hctx;
-	unsigned int i;
-
-	queue_for_each_hw_ctx(q, hctx, i)
-		free_cpumask_var(hctx->cpumask);
-}
-
 static int blk_mq_init_hctx(struct request_queue *q,
 		struct blk_mq_tag_set *set,
 		struct blk_mq_hw_ctx *hctx, unsigned hctx_idx)
@@ -2333,7 +2323,6 @@ static void blk_mq_realloc_hw_ctxs(struct blk_mq_tag_set *set,
 			if (hctx->tags)
 				blk_mq_free_map_and_requests(set, j);
 			blk_mq_exit_hctx(q, set, hctx, j);
-			free_cpumask_var(hctx->cpumask);
 			kobject_put(&hctx->kobj);
 			hctxs[j] = NULL;
 
@@ -2446,7 +2435,6 @@ void blk_mq_free_queue(struct request_queue *q)
 	blk_mq_del_queue_tag_set(q);
 
 	blk_mq_exit_hw_queues(q, set, set->nr_hw_queues);
-	blk_mq_free_hw_queues(q, set);
 }
 
 /* Basically redo blk_mq_init_queue with queue frozen */