cfq-iosched: free cic_index if blkio_alloc_blkg_stats fails

If we fail allocating the blkpg stats, we free cfqd and cfgq.
But we need to free the IDA cfqd->cic_index as well.
Signed-off-by: majianpeng <majianpeng@gmail.com>
Cc: stable@kernel.org
Signed-off-by: Jens Axboe <axboe@kernel.dk>

block/cfq-iosched.c

@@ -4036,6 +4036,11 @@ static void *cfq_init_queue(struct request_queue *q)
 
 	if (blkio_alloc_blkg_stats(&cfqg->blkg)) {
 		kfree(cfqg);
+
+		spin_lock(&cic_index_lock);
+		ida_remove(&cic_index_ida, cfqd->cic_index);
+		spin_unlock(&cic_index_lock);
+
 		kfree(cfqd);
 		return NULL;
 	}