Re: [PATCH 1/6] libata: Signal that our SATL supports WRITE SAME(16) with UNMAP

[Douglas Gilbert <dgilbert@interlog.com>]

On 10-08-23 02:22 PM, Douglas Gilbert wrote:
> On 10-08-23 04:32 AM, Tejun Heo wrote:
>> On 08/19/2010 05:48 PM, Martin K. Petersen wrote:
>>> Until now identifying that a device supports WRITE SAME(16) with the
>>> UNMAP bit set has been black magic. Implement support for the new (SBC3
>>> r24) Thin Provisioning VPD page and the TPWS bit.
>>>
>>> Signed-off-by: Martin K. Petersen<martin.petersen@oracle.com>
>>> ---
>>> drivers/ata/libata-scsi.c | 13 +++++++++++++
>>> 1 files changed, 13 insertions(+), 0 deletions(-)
>>>
>>> diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
>>> index a54273d..e280ae6 100644
>>> --- a/drivers/ata/libata-scsi.c
>>> +++ b/drivers/ata/libata-scsi.c
>>> @@ -2001,6 +2001,7 @@ static unsigned int ata_scsiop_inq_00(struct
>>> ata_scsi_args *args, u8 *rbuf)
>>> 0x89, /* page 0x89, ata info page */
>>> 0xb0, /* page 0xb0, block limits page */
>>> 0xb1, /* page 0xb1, block device characteristics page */
>>> + 0xb2, /* page 0xb2, thin provisioning page */
>>> };
>>>
>>> rbuf[3] = sizeof(pages); /* number of supported VPD pages */
>>> @@ -2172,6 +2173,15 @@ static unsigned int ata_scsiop_inq_b1(struct
>>> ata_scsi_args *args, u8 *rbuf)
>>> return 0;
>>> }
>>>
>>> +static unsigned int ata_scsiop_inq_b2(struct ata_scsi_args *args, u8
>>> *rbuf)
>>> +{
>>> + rbuf[1] = 0xb1;
>>> + rbuf[3] = 0x3c;
>>> + rbuf[5] = 1<< 6; /* TPWS */
>>
>> I would love a bit more documentation here.
>
> Yes, that style comes from my code in scsi_debug and
> some of my utilities. Recently I added some more
> documentation, just prior the the function:
>
> /* SCSI Thin Provisioning VPD page: SBC-3 rev 22 or later */
>
> I see no point in commenting the individual code lines.
> Just follow that reference ...
>
> And when I do then I see that rbuf[3] should be 4 (not 0x3c)
> unless the DP bit is set.

... and of course rbuf[1] should be 0xb2 . Martin ????
The rbuf[5] line is correct :-)

Doug Gilbert