Re: [PATCH 1/3] ata: libata-scsi: Fix ata_msense_control_ata_feature()

[Igor Pylypiv <ipylypiv@google.com>]

On Wed, Apr 16, 2025 at 05:42:36PM +0900, Damien Le Moal wrote:
> For the ATA features subpage of the control mode page, the T10 SAT-6
> specifications state that:
> 
> For a MODE SENSE command, the SATL shall return the CDL_CTRL field value
> that was last set by an application client.
> 
> However, the function ata_msense_control_ata_feature() always sets the
> CDL_CTRL field to the 0x02 value to indicate support for the CDL T2A and
> T2B pages. This is thus incorrect and the value 0x02 must be reported
> only after the user enables the CDL feature, which is indicated with the
> ATA_DFLAG_CDL_ENABLED device flag. When this flag is not set, the
> CDL_CTRL field of the ATA feature subpage of the control mode page must
> report a value of 0x00.
> 
> Fix ata_msense_control_ata_feature() to report the correct values for
> the CDL_CTRL field, according to the enable/disable state of the device
> CDL feature.
> 
> Fixes: df60f9c64576 ("scsi: ata: libata: Add ATA feature control sub-page translation")
> Cc: stable@vger.kernel.org
> Signed-off-by: Damien Le Moal <dlemoal@kernel.org>

Reviewed-by: Igor Pylypiv <ipylypiv@google.com>

> ---
>  drivers/ata/libata-scsi.c | 5 +++--
>  1 file changed, 3 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
> index 2796c0da8257..e6c652b8a541 100644
> --- a/drivers/ata/libata-scsi.c
> +++ b/drivers/ata/libata-scsi.c
> @@ -2453,8 +2453,9 @@ static unsigned int ata_msense_control_ata_feature(struct ata_device *dev,
>  	 */
>  	put_unaligned_be16(ATA_FEATURE_SUB_MPAGE_LEN - 4, &buf[2]);
>  
> -	if (dev->flags & ATA_DFLAG_CDL)
> -		buf[4] = 0x02; /* Support T2A and T2B pages */
> +	if ((dev->flags & ATA_DFLAG_CDL) &&

Do we need to check the ATA_DFLAG_CDL flag? If ATA_DFLAG_CDL_ENABLED is set
then ATA_DFLAG_CDL must be set as well?

ata_mselect_control_ata_feature() only checks the ATA_DFLAG_CDL_ENABLED flag.

> +	    (dev->flags & ATA_DFLAG_CDL_ENABLED))
> +		buf[4] = 0x02; /* T2A and T2B pages enabled */
>  	else
>  		buf[4] = 0;
>  
> -- 
> 2.49.0
> 
> 

Thanks,
Igor