[PATCH v5 3/6] scsi: ufs: core: Fix double completion in ufshcd_clear_lu_cmds()

[Stanley Jhu]

In SDB mode, ufshcd_clear_lu_cmds() clears the request slot in the
controller and completes the request, but leaves its bit set in
hba->outstanding_reqs. ufshcd_poll() treats a request whose bit is set
in hba->outstanding_reqs and clear in the doorbell register as finished,
so the next ufshcd_poll() completes the same request again and unmaps
its DMA buffers twice.

Clear the bit with ufshcd_clear_outstanding_reqs() before completing the
request, and complete it only if the bit was still set. If ufshcd_poll()
has already completed the request, the bit is already clear and
ufshcd_clear_lu_cmds() skips it.

Fixes: f18fac1e2b72 ("scsi: ufs: core: Rework ufshcd_eh_device_reset_handler()")
Cc: stable@xxxxxxxxxxxxxxx
Reviewed-by: Bean Huo <beanhuo@xxxxxxxxxx>
Reviewed-by: Peter Wang <peter.wang@xxxxxxxxxxxx>
Reviewed-by: Bart Van Assche <bvanassche@xxxxxxx>
Signed-off-by: Stanley Jhu <stanleyjhu@xxxxxxxxxx>
---
 drivers/ufs/core/ufshcd.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index 1db572f84971..68b53f89f8c6 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -7987,7 +7987,8 @@ static bool ufshcd_clear_lu_cmds(struct request *req, void *priv)
 		return true;
 	}
 
-	ufshcd_compl_one_cqe(hba, tag, NULL);
+	if (ufshcd_clear_outstanding_reqs(hba, BIT(tag)))
+		ufshcd_compl_one_cqe(hba, tag, NULL);
 	return true;
 }
 
-- 
2.56.0.218.g1ec904b173-goog