Re: [PATCH] blk-mq: Fix spurious debugfs directory creation during initialization

From: Jens Axboe
Date: Fri Apr 16 2021 - 17:17:28 EST


On 4/7/21 11:59 AM, Saravanan D wrote:
> blk_mq_debugfs_register_sched_hctx() called from
> device_add_disk()->elevator_init_mq()->blk_mq_init_sched()
> initialization sequence does not have relevant parent directory
> setup and thus spuriously attempts "sched" directory creation
> from root mount of debugfs for every hw queue detected on the
> block device
>
> dmesg
> ...
> debugfs: Directory 'sched' with parent '/' already present!
> debugfs: Directory 'sched' with parent '/' already present!
> .
> .
> debugfs: Directory 'sched' with parent '/' already present!
> ...
>
> The parent debugfs directory for hw queues get properly setup
> device_add_disk()->blk_register_queue()->blk_mq_debugfs_register()
> ->blk_mq_debugfs_register_hctx() later in the block device
> initialization sequence.
>
> A simple check for debugfs_dir has been added to thwart premature
> debugfs directory/file creation attempts.

Applied, thanks.

--
Jens Axboe