[PATCH v2 5/5] scsi: ufs: core: Clear stale UIC result byte before peer DME retries

[Stanley Jhu <stanleyjhu@google.com>]

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(). In ufshcd_dme_set_attr(),
ufshcd_uic_cmd_compl() also overwrites argument3 with the register
readback before the next attempt.

Clear the result byte and restore argument3 in ufshcd_dme_set_attr()
when an attempt fails.

Fixes: 64238fbd15ea ("scsi: ufs: add retries to dme_peer get and set attribute")
Cc: stable@vger.kernel.org
Reviewed-by: Bean Huo <beanhuo@micron.com>
Signed-off-by: Stanley Jhu <stanleyjhu@google.com>
---
Changes in v2:
- Clear argument2's result byte and restore argument3 (MIBvalue_W) in
  the failure path instead of before the first attempt. Kept Bean's
  Reviewed-by; Bean, please let me know if you would like to look again.

 drivers/ufs/core/ufshcd.c | 9 +++++++--
 1 file changed, 7 insertions(+), 2 deletions(-)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index bcc2512bf34b..7532fd916bfd 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -4400,9 +4400,12 @@ int ufshcd_dme_set_attr(struct ufs_hba *hba, u32 attr_sel,
 	do {
 		/* for peer attributes we retry upon failure */
 		ret = ufshcd_send_uic_cmd(hba, &uic_cmd);
-		if (ret)
+		if (ret) {
 			dev_dbg(hba->dev, "%s: attr-id 0x%x val 0x%x error code %d\n",
 				set, UIC_GET_ATTR_ID(attr_sel), mib_val, ret);
+			uic_cmd.argument2 &= ~MASK_UIC_COMMAND_RESULT;
+			uic_cmd.argument3 = mib_val;
+		}
 	} while (ret && peer && --retries);
 
 	if (ret)
@@ -4467,9 +4470,11 @@ int ufshcd_dme_get_attr(struct ufs_hba *hba, u32 attr_sel,
 	do {
 		/* for peer attributes we retry upon failure */
 		ret = ufshcd_send_uic_cmd(hba, &uic_cmd);
-		if (ret)
+		if (ret) {
 			dev_dbg(hba->dev, "%s: attr-id 0x%x error code %d\n",
 				get, UIC_GET_ATTR_ID(attr_sel), ret);
+			uic_cmd.argument2 &= ~MASK_UIC_COMMAND_RESULT;
+		}
 	} while (ret && peer && --retries);
 
 	if (ret)
-- 
2.56.0.385.gd3acb90ef8-goog