elevator: printk a warning if switching to a new io scheduler fails

printk a warning to indicate that the io scheduler has been set to none if switching to a new io scheduler fails. Suggested-by: Christoph Hellwig <[email protected]> Signed-off-by: Jinlong Chen <[email protected]> Reviewed-by: Christoph Hellwig <[email protected]> Link: https://lore.kernel.org/r/d51ed0fb457db7a4f9cbb0dbce36d534e22be457.1669126766.git.nickyc975@zju.edu.cn Signed-off-by: Jens Axboe <[email protected]>
wafgo · Nov 23, 2022 · e0cca8b · e0cca8b
1 parent ac1171b
commit e0cca8b
Showing 1 changed file with 6 additions and 0 deletions.
diff --git a/block/elevator.c b/block/elevator.c
@@ -683,6 +683,12 @@ int elevator_switch(struct request_queue *q, struct elevator_type *new_e)
 out_unfreeze:
 	blk_mq_unquiesce_queue(q);
 	blk_mq_unfreeze_queue(q);
+
+	if (ret) {
+		pr_warn("elv: switch to \"%s\" failed, falling back to \"none\"\n",
+			new_e->elevator_name);
+	}
+
 	return ret;
 }