Re: [PATCH] scsi: make "access_state" sysfs attribute always visible

[Hannes Reinecke <hare@suse.de>]

On 1/27/22 15:13, mwilck@suse.com wrote:
> From: Martin Wilck <mwilck@suse.com>
> 
> If a SCSI device handler module is loaded after some SCSI devices
> have already been probed (e.g. via request_module() by dm-multipath),
> the "access_state" and "preferred_path" sysfs attributes remain invisible for
> these devices, although the handler is attached and live. The reason is
> that the visibility is only checked when the sysfs attribute group is
> first created. This results in an inconsistent user experience depending
> on the load order of SCSI low-level drivers vs. device handler modules.
> 
> This patch changes user space API: attempting to read the "access_state"
> or "preferred_path" attributes will now result in -EINVAL rather than
> -ENODEV for devices that have no device handler, and tests for the existence
> of these attributes will have a different result.
> 
> Signed-off-by: Martin Wilck <mwilck@suse.com>
> Reviewed-by: Christoph Hellwig <hch@lst.de>
> ---
>   drivers/scsi/scsi_sysfs.c | 8 --------
>   1 file changed, 8 deletions(-)
> 
> diff --git a/drivers/scsi/scsi_sysfs.c b/drivers/scsi/scsi_sysfs.c
> index f1e0c131b77c..226a50944c00 100644
> --- a/drivers/scsi/scsi_sysfs.c
> +++ b/drivers/scsi/scsi_sysfs.c
> @@ -1228,14 +1228,6 @@ static umode_t scsi_sdev_attr_is_visible(struct kobject *kobj,
>   	    !sdev->host->hostt->change_queue_depth)
>   		return 0;
>   
> -#ifdef CONFIG_SCSI_DH
> -	if (attr == &dev_attr_access_state.attr &&
> -	    !sdev->handler)
> -		return 0;
> -	if (attr == &dev_attr_preferred_path.attr &&
> -	    !sdev->handler)
> -		return 0;
> -#endif
>   	return attr->mode;
>   }
>   
Reviewed-by: Hannes Reinecke <hare@suse.de>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		           Kernel Storage Architect
hare@suse.de			                  +49 911 74053 688
SUSE Software Solutions Germany GmbH, Maxfeldstr. 5, 90409 Nürnberg
HRB 36809 (AG Nürnberg), GF: Felix Imendörffer