Re: [PATCH] scsi_dh_alua: remove check for ASC 24h when ILLEGAL_REQUEST returned on RTPG w/extended header

From: Douglas Gilbert <dgilbert@interlog.com>
To: "Ewan D. Milne" <emilne@redhat.com>, linux-scsi@vger.kernel.org
Cc: hare@suse.de
Subject: Re: [PATCH] scsi_dh_alua: remove check for ASC 24h when ILLEGAL_REQUEST returned on RTPG w/extended header
Date: Thu, 1 Apr 2021 00:24:34 -0400	[thread overview]
Message-ID: <2c505c60-9ba0-9ce6-46a6-e6edea2ada03@interlog.com> (raw)
In-Reply-To: <20210331201154.20348-1-emilne@redhat.com>

On 2021-03-31 4:11 p.m., Ewan D. Milne wrote:
> Some arrays return ILLEGAL_REQUEST with ASC 00h if they don't support the
> extended header, so remove the check for INVALID FIELD IN CDB.

Wow. Referring to the 18 byte sense buffer as an extended header sounds
like it comes from the transition of SCSI-1 to SCSI-2, about 30 years ago.
Those arrays need to be named and shamed.

Doug Gilbert
Hmm, it is April first ...

> Signed-off-by: Ewan D. Milne <emilne@redhat.com>
> ---
>   drivers/scsi/device_handler/scsi_dh_alua.c | 5 +++--
>   1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/scsi/device_handler/scsi_dh_alua.c b/drivers/scsi/device_handler/scsi_dh_alua.c
> index e42390333c6e..c4c2f23cf79f 100644
> --- a/drivers/scsi/device_handler/scsi_dh_alua.c
> +++ b/drivers/scsi/device_handler/scsi_dh_alua.c
> @@ -587,10 +587,11 @@ static int alua_rtpg(struct scsi_device *sdev, struct alua_port_group *pg)
>   		 * even though it shouldn't according to T10.
>   		 * The retry without rtpg_ext_hdr_req set
>   		 * handles this.
> +		 * Note:  some arrays return a sense key of ILLEGAL_REQUEST
> +		 * with ASC 00h if they don't support the extended header.
>   		 */
>   		if (!(pg->flags & ALUA_RTPG_EXT_HDR_UNSUPP) &&
> -		    sense_hdr.sense_key == ILLEGAL_REQUEST &&
> -		    sense_hdr.asc == 0x24 && sense_hdr.ascq == 0) {
> +		    sense_hdr.sense_key == ILLEGAL_REQUEST) {
>   			pg->flags |= ALUA_RTPG_EXT_HDR_UNSUPP;
>   			goto retry;
>   		}
> 