[PATCH 3/3] scsi: ufs: core: Clear stale UIC result byte before peer DME retries

[Stanley Jhu]

Peer DME get and set retry a failed attempt with the same struct
uic_command. UIC completion ORs the ConfigResultCode into
argument2[7:0], and nothing clears it before the next attempt. Once an
attempt fails, every retry keeps reporting that error code, even when
the device returns success, so a transient failure becomes a hard
failure after three retries. Each such retry also triggers the
WARN_ON_ONCE() in ufshcd_dispatch_uic_cmd().

Clear the result byte before each attempt.

Fixes: 64238fbd15ea ("scsi: ufs: add retries to dme_peer get and set attribute")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Stanley Jhu <stanleyjhu@xxxxxxxxxx>
---
 drivers/ufs/core/ufshcd.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index bcc2512bf34b..9adb3b576e28 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -4398,6 +4398,7 @@ int ufshcd_dme_set_attr(struct ufs_hba *hba, u32 attr_sel,
 	int retries = UFS_UIC_COMMAND_RETRIES;
 
 	do {
+		uic_cmd.argument2 &= ~MASK_UIC_COMMAND_RESULT;
 		/* for peer attributes we retry upon failure */
 		ret = ufshcd_send_uic_cmd(hba, &uic_cmd);
 		if (ret)
@@ -4465,6 +4466,7 @@ int ufshcd_dme_get_attr(struct ufs_hba *hba, u32 attr_sel,
 	}
 
 	do {
+		uic_cmd.argument2 &= ~MASK_UIC_COMMAND_RESULT;
 		/* for peer attributes we retry upon failure */
 		ret = ufshcd_send_uic_cmd(hba, &uic_cmd);
 		if (ret)
-- 
2.56.0.385.gd3acb90ef8-goog