[dm-devel] [for-4.16 PATCH v4 3/4] block: allow gendisk's request_queue registration to be deferred

[Bart Van Assche]

On Thu, 2018-01-11 at 15:14 -0500, Mike Snitzer wrote:
> -void device_add_disk(struct device *parent, struct gendisk *disk)
> +void device_add_disk_no_queue_reg(struct device *parent, struct gendisk *disk)
>  {
>  	dev_t devt;
>  	int retval;
> @@ -682,7 +682,6 @@ void device_add_disk(struct device *parent, struct gendisk *disk)
>  				    exact_match, exact_lock, disk);
>  	}
>  	register_disk(parent, disk);
> -	blk_register_queue(disk);
>  
>  	/*
>  	 * Take an extra ref on queue which will be put on disk_release()
> @@ -693,6 +692,21 @@ void device_add_disk(struct device *parent, struct gendisk *disk)
>  	disk_add_events(disk);
>  	blk_integrity_add(disk);
>  }
> +EXPORT_SYMBOL(device_add_disk_no_queue_reg);

Hello Mike,

This change can increase the time between the generation of the disk uevent
and the registration of the request queue sysfs attributes. Can this cause
any udev rules to fail?

Thanks,

Bart.