Re: [PATCH v4 1/8] ata: libata-scsi: Fix offsets for the fixed format sense data

Niklas Cassel
2024-07-01T21:10:02Z

On Mon, Jul 01, 2024 at 07:57:51PM +0000, Igor Pylypiv wrote:
> Correct the ATA PASS-THROUGH fixed format sense data offsets to conform
> to SPC-6 and SAT-5 specifications. Additionally, set the VALID bit to
> indicate that the INFORMATION field contains valid information.
>
> INFORMATION
> ===========
>
> SAT-5 Table 212 — "Fixed format sense data INFORMATION field for the ATA
> PASS-THROUGH commands" defines the following format:
>
> +------+------------+
> | Byte | Field |
> +------+------------+
> | 0 | ERROR |
> | 1 | STATUS |
> | 2 | DEVICE |
> | 3 | COUNT(7:0) |
> +------+------------+
>
> SPC-6 Table 48 - "Fixed format sense data" specifies that the INFORMATION
> field starts at byte 3 in sense buffer resulting in the following offsets
> for the ATA PASS-THROUGH commands:
>
> +------------+-------------------------+
> | Field | Offset in sense buffer |
> +------------+-------------------------+
> | ERROR | 3 |
> | STATUS | 4 |
> | DEVICE | 5 |
> | COUNT(7:0) | 6 |
> +------------+-------------------------+
>
> COMMAND-SPECIFIC INFORMATION
> ============================
>
> SAT-5 Table 213 - "Fixed format sense data COMMAND-SPECIFIC INFORMATION
> field for ATA PASS-THROUGH" defines the following format:
>
> +------+-------------------+
> | Byte | Field |
> +------+-------------------+
> | 0 | FLAGS | LOG INDEX |
> | 1 | LBA (7:0) |
> | 2 | LBA (15:8) |
> | 3 | LBA (23:16) |
> +------+-------------------+
>
> SPC-6 Table 48 - "Fixed format sense data" specifies that
> the COMMAND-SPECIFIC-INFORMATION field starts at byte 8
> in sense buffer resulting in the following offsets for
> the ATA PASS-THROUGH commands:
>
> Offsets of these fields in the fixed sense format are as follows:
>
> +-------------------+-------------------------+
> | Field | Offset in sense buffer |
> +-------------------+-------------------------+
> | FLAGS | LOG INDEX | 8 |
> | LBA (7:0) | 9 |
> | LBA (15:8) | 10 |
> | LBA (23:16) | 11 |
> +-------------------+-------------------------+
>
> Reported-by: Akshat Jain <akshatzen@google.com>
> Fixes: 11093cb1ef56 ("libata-scsi: generate correct ATA pass-through sense")
> Cc: stable@vger.kernel.org
> Reviewed-by: Hannes Reinecke <hare@suse.de>
> Signed-off-by: Igor Pylypiv <ipylypiv@google.com>
> ---
> drivers/ata/libata-scsi.c | 26 +++++++++++++-------------
> 1 file changed, 13 insertions(+), 13 deletions(-)
>
> diff --git a/drivers/ata/libata-scsi.c b/drivers/ata/libata-scsi.c
> index bb4d30d377ae..a9e44ad4c2de 100644
> --- a/drivers/ata/libata-scsi.c
> +++ b/drivers/ata/libata-scsi.c
> @@ -855,7 +855,6 @@ static void ata_gen_passthru_sense(struct ata_queued_cmd *qc)
> struct scsi_cmnd *cmd = qc->scsicmd;
> struct ata_taskfile *tf = &qc->result_tf;
> unsigned char *sb = cmd->sense_buffer;
> - unsigned char *desc = sb + 8;
> u8 sense_key, asc, ascq;
>
> memset(sb, 0, SCSI_SENSE_BUFFERSIZE);
> @@ -877,7 +876,8 @@ static void ata_gen_passthru_sense(struct ata_queued_cmd *qc)
> scsi_build_sense(cmd, 1, RECOVERED_ERROR, 0, 0x1D);
> }
>
> - if ((cmd->sense_buffer[0] & 0x7f) >= 0x72) {
> + if ((sb[0] & 0x7f) >= 0x72) {
> + unsigned char *desc;
> u8 len;
>
> /* descriptor format */
> @@ -916,21 +916,21 @@ static void ata_gen_passthru_sense(struct ata_queued_cmd *qc)
> }
> } else {
> /* Fixed sense format */
> - desc[0] = tf->error;
> - desc[1] = tf->status;
> - desc[2] = tf->device;
> - desc[3] = tf->nsect;
> - desc[7] = 0;
> + sb[0] |= 0x80;
> + sb[3] = tf->error;
> + sb[4] = tf->status;
> + sb[5] = tf->device;
> + sb[6] = tf->nsect;
> if (tf->flags & ATA_TFLAG_LBA48) {
> - desc[8] |= 0x80;
> + sb[8] |= 0x80;
> if (tf->hob_nsect)
> - desc[8] |= 0x40;
> + sb[8] |= 0x40;
> if (tf->hob_lbal || tf->hob_lbam || tf->hob_lbah)
> - desc[8] |= 0x20;
> + sb[8] |= 0x20;
> }
> - desc[9] = tf->lbal;
> - desc[10] = tf->lbam;
> - desc[11] = tf->lbah;
> + sb[9] = tf->lbal;
> + sb[10] = tf->lbam;
> + sb[11] = tf->lbah;
> }
> }
>
> --
> 2.45.2.803.g4e1b14247a-goog
>

Reviewed-by: Niklas Cassel <cassel@kernel.org>