From 1314b3eac06cdb6210fe6d1f4e3dc0b0712a6bdb Mon Sep 17 00:00:00 2001 From: Jan Kara Date: Wed, 6 Nov 2019 11:48:57 +0100 Subject: [PATCH] block: Warn if elevator= parameter is used With transition to blk-mq, the elevator= kernel argument was removed as it makes less and less sense with the current variety of devices. Since this may surprise some users and there are advices on the Internet that still suggest to use it, let's at least warn if the parameter is used. Reviewed-by: Jeff Moyer Signed-off-by: Jan Kara Signed-off-by: Jens Axboe --- block/elevator.c | 9 +++++++++ 1 file changed, 9 insertions(+) diff --git a/block/elevator.c b/block/elevator.c index 5437059c92615..0b1db9afb5867 100644 --- a/block/elevator.c +++ b/block/elevator.c @@ -831,3 +831,12 @@ struct request *elv_rb_latter_request(struct request_queue *q, return NULL; } EXPORT_SYMBOL(elv_rb_latter_request); + +static int __init elevator_setup(char *str) +{ + pr_warn("Kernel parameter elevator= does not have any effect anymore.\n" + "Please use sysfs to set IO scheduler for individual devices.\n"); + return 1; +} + +__setup("elevator=", elevator_setup); -- 2.39.5