scsi: libsas: Set data_dir as DMA_NONE if libata marks qc as NODATA
authorLuo Jiaxing <luojiaxing@huawei.com>
Wed, 26 Aug 2020 07:24:26 +0000 (15:24 +0800)
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Wed, 23 Sep 2020 06:46:09 +0000 (08:46 +0200)
commit5bfc2341c588f42190186b831ea6e87c13301ea8
tree49b22bea58ca1b49dd689507d0195114590eea57
parentacbf02df3355e90e08378fd7fa041635ff1459b4
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 <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