[PATCH v5 5/6] scsi: ufs: core: Remove completed-without-interrupt path in ufshcd_abort()

[Stanley Jhu]

In SDB mode, a command that times out right as the controller finishes
it can be completed twice:

1. The command times out and scsi_timeout() schedules ufshcd_abort().
2. The controller finishes the command and clears its doorbell bit in
   REG_UTP_TRANSFER_REQ_DOOR_BELL, while the completion handler has not
   yet cleared BIT(tag) in hba->outstanding_reqs.
3. ufshcd_abort() sees the doorbell bit clear and calls
   __ufshcd_transfer_req_compl() without clearing BIT(tag) in
   hba->outstanding_reqs.
4. The normal completion handler or the logical unit reset that follows
   sees BIT(tag) still set in hba->outstanding_reqs and completes the
   same command a second time.

This branch only exists for a rare corner case, a completion interrupt
that is lost or arrives late. Remove it to simplify the abort path and
leave such a command to the SCSI error handler, like any other command
that cannot be aborted. The cost is a slower recovery in this corner
case, which is acceptable since it only happens after a timeout.

Fixes: 169f5eb28869 ("scsi: ufs: Optimize SCSI command processing")
Cc: stable@xxxxxxxxxxxxxxx
Link: https://lore.kernel.org/r/fdb5c391-01ef-4a23-94c2-4f3853909348@xxxxxxx
Signed-off-by: Stanley Jhu <stanleyjhu@xxxxxxxxxx>
---
 drivers/ufs/core/ufshcd.c | 9 ---------
 1 file changed, 9 deletions(-)

diff --git a/drivers/ufs/core/ufshcd.c b/drivers/ufs/core/ufshcd.c
index ff5977f7da68..87efa2925867 100644
--- a/drivers/ufs/core/ufshcd.c
+++ b/drivers/ufs/core/ufshcd.c
@@ -8180,15 +8180,6 @@ static int ufshcd_abort(struct scsi_cmnd *cmd)
 	}
 	hba->req_abort_count++;
 
-	if (!hba->mcq_enabled && !(reg & (1 << tag))) {
-		/* only execute this code in single doorbell mode */
-		dev_err(hba->dev,
-		"%s: cmd was completed, but without a notifying intr, tag = %d",
-		__func__, tag);
-		__ufshcd_transfer_req_compl(hba, 1UL << tag);
-		goto release;
-	}
-
 	/*
 	 * Task abort to the device W-LUN is illegal. When this command
 	 * will fail, due to spec violation, scsi err handling next step
-- 
2.56.0.218.g1ec904b173-goog