From d0e73696ab4932be094dbd3cfff2f9122d639d8c Mon Sep 17 00:00:00 2001 From: Luo Jiaxing Date: Wed, 26 Aug 2020 15:24:26 +0800 Subject: [PATCH] scsi: libsas: Set data_dir as DMA_NONE if libata marks qc as NODATA [ 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@huawei.com Reviewed-by: John Garry Reviewed-by: Jason Yan Signed-off-by: Luo Jiaxing Signed-off-by: Martin K. Petersen Signed-off-by: Sasha Levin --- 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 70be4425ae0b..470e11b42820 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; -- 2.20.1