From: Luo Jiaxing luojiaxing@huawei.com
[ Upstream commit 53de092f47ff40e8d4d78d590d95819d391bf2e0 ]
It was discovered that sdparm will fail when attempting to disable write cache on a SATA disk connected via libsas.
In the ATA command set the write cache state is controlled through the SET FEATURES operation. This is roughly corresponds to MODE SELECT in SCSI and the latter command is what is used in the SCSI-ATA translation layer. A subtle difference is that a MODE SELECT carries data whereas SET FEATURES is defined as a non-data command in ATA.
Set the DMA data direction to DMA_NONE if the requested ATA command is identified as non-data.
[mkp: commit desc]
Fixes: fa1c1e8f1ece ("[SCSI] Add SATA support to libsas") Link: https://lore.kernel.org/r/1598426666-54544-1-git-send-email-luojiaxing@huawe... Reviewed-by: John Garry john.garry@huawei.com Reviewed-by: Jason Yan yanaijie@huawei.com Signed-off-by: Luo Jiaxing luojiaxing@huawei.com Signed-off-by: Martin K. Petersen martin.petersen@oracle.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/scsi/libsas/sas_ata.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/scsi/libsas/sas_ata.c b/drivers/scsi/libsas/sas_ata.c index 87f5e694dbedd..b820c3a022eac 100644 --- a/drivers/scsi/libsas/sas_ata.c +++ b/drivers/scsi/libsas/sas_ata.c @@ -227,7 +227,10 @@ static unsigned int sas_ata_qc_issue(struct ata_queued_cmd *qc) task->num_scatter = si; }
- task->data_dir = qc->dma_dir; + if (qc->tf.protocol == ATA_PROT_NODATA) + task->data_dir = DMA_NONE; + else + task->data_dir = qc->dma_dir; task->scatter = qc->sg; task->ata_task.retry_count = 1; task->task_state_flags = SAS_TASK_STATE_PENDING;