[PATCH 2/4] elevator: printk a warning if switching to a new io scheduler fails

Jinlong Chen
2022-11-22T14:22:04Z

printk a warning to indicate that the io scheduler has been set to none
if switching to a new io scheduler fails.

Signed-off-by: Jinlong Chen <nickyc975@zju.edu.cn>
---
block/elevator.c | 6 ++++++
1 file changed, 6 insertions(+)

diff --git a/block/elevator.c b/block/elevator.c
index 01aa9f38f22e..1fa45717b1d6 100644
--- 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;
}

--
2.34.1