On 2/15/22 02:56, John Garry wrote:
> On 14/02/2022 02:17, Damien Le Moal wrote:
>> To detect for the DMA_NONE (no data transfer) DMA direction,
>> sas_ata_qc_issue() tests if the command protocol is ATA_PROT_NODATA.
>> This test does not include the ATA_CMD_NCQ_NON_DATA command as this
>> command protocol is defined as ATA_PROT_NCQ_NODATA (equal to
>> ATA_PROT_FLAG_NCQ) and not as ATA_PROT_NODATA.
>>
>> To include both NCQ and non-NCQ commands when testing for the DMA_NONE
>> DMA direction, use "!ata_is_data()".
>>
>> Fixes: 176ddd89171d ("scsi: libsas: Reset num_scatter if libata marks qc as NODATA")
>> Cc: stable@xxxxxxxxxxxxxxx
>> Signed-off-by: Damien Le Moal <damien.lemoal@xxxxxxxxxxxxxxxxxx>
>
> Regardless of comment below:
> Reviewed-by: John Garry <john.garry@xxxxxxxxxx>
>
>> ---
>> drivers/scsi/libsas/sas_ata.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c
>> index e0030a093994..50f779088b6e 100644
>> --- a/drivers/scsi/libsas/sas_ata.c
>> +++ b/drivers/scsi/libsas/sas_ata.c
>> @@ -197,7 +197,7 @@ static unsigned int sas_ata_qc_issue(struct ata_queued_cmd *qc)
>> task->total_xfer_len = qc->nbytes;
>> task->num_scatter = qc->n_elem;
>> task->data_dir = qc->dma_dir;
>> - } else if (qc->tf.protocol == ATA_PROT_NODATA) {
>> + } else if (!ata_is_data(qc->tf.protocol)) {
>
> I was thinking ata_is_dma() would be more appropiate, but I suppose we
> don't have to use DMA.
That was my first thought, but using ata_is_dma() would not include PIO
case, so that would not work.
>
>> task->data_dir = DMA_NONE; > } else {
>> for_each_sg(qc->sg, sg, qc->n_elem, si)
>
--
Damien Le Moal
Western Digital Research
