[PATCH v4 2/5] scsi: ufs: Use DBD setting in mode sense

[Can Guo]

UFS standards requires DBD field to be set to 1 in mode sense(10).

Some card vendors are more strict and check the DBD field, hence
respond with CHECK_CONDITION (Sense key set to ILLEGAL_REQUEST and
ASC set to INVALID FIELD IN CDB).
When host send mode sense for page caching, as a result of the
CHECK_CONDITION response, host assumes that the device doesn't support
the cache feature and doesn't send SYNCHRONIZE_CACHE commands to flush
the device cache. This can result in data corruption in case of sudden
power down, when there is data stored in the device cache.

This patch fixes the DBD field setting as required in UFS standards.

Signed-off-by: Can Guo <cang@xxxxxxxxxxxxxx>
---
 drivers/scsi/ufs/ufshcd.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/scsi/ufs/ufshcd.c b/drivers/scsi/ufs/ufshcd.c
index c28c144..5484177 100644
--- a/drivers/scsi/ufs/ufshcd.c
+++ b/drivers/scsi/ufs/ufshcd.c
@@ -4596,6 +4596,9 @@ static int ufshcd_slave_alloc(struct scsi_device *sdev)
 	/* Mode sense(6) is not supported by UFS, so use Mode sense(10) */
 	sdev->use_10_for_ms = 1;
 
+	/* DBD field should be set to 1 in mode sense(10) */
+	sdev->set_dbd_for_ms = 1;
+
 	/* allow SCSI layer to restart the device in case of errors */
 	sdev->allow_restart = 1;
 
-- 
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