From e20f80b9b163dc402dca115eed0affba6df5ebb5 Mon Sep 17 00:00:00 2001
From: Brian King <brking@linux.vnet.ibm.com>
Date: Tue, 19 Oct 2021 10:21:29 -0500
Subject: [PATCH] scsi: ibmvfc: Fix up duplicate response detection

References: bsc#1191867 ltc#194757 stable-5.14.16
Patch-mainline: v5.15
Git-commit: e20f80b9b163dc402dca115eed0affba6df5ebb5

Commit a264cf5e81c7 ("scsi: ibmvfc: Fix command state accounting and stale
response detection") introduced a regression in detecting duplicate
responses. This was observed in test where a command was sent to the VIOS
and completed before ibmvfc_send_event() set the active flag to 1, which
resulted in the atomic_dec_if_positive() call in ibmvfc_handle_crq()
thinking this was a duplicate response, which resulted in scsi_done() not
getting called, so we then hit a SCSI command timeout for this command once
the timeout expires.  This simply ensures the active flag gets set prior to
making the hcall to send the command to the VIOS, in order to close this
window.

Link: https://lore.kernel.org/r/20211019152129.16558-1-brking@linux.vnet.ibm.com
Fixes: a264cf5e81c7 ("scsi: ibmvfc: Fix command state accounting and stale response detection")
Cc: stable@vger.kernel.org
Acked-by: Tyrel Datwyler <tyreld@linux.ibm.com>
Signed-off-by: Brian King <brking@linux.vnet.ibm.com>
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 drivers/scsi/ibmvscsi/ibmvfc.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c
index 1f1586ad48fe..01f79991bf4a 100644
--- a/drivers/scsi/ibmvscsi/ibmvfc.c
+++ b/drivers/scsi/ibmvscsi/ibmvfc.c
@@ -1696,6 +1696,7 @@ static int ibmvfc_send_event(struct ibmvfc_event *evt,
 
 	spin_lock_irqsave(&evt->queue->l_lock, flags);
 	list_add_tail(&evt->queue_list, &evt->queue->sent);
+	atomic_set(&evt->active, 1);
 
 	mb();
 
@@ -1710,6 +1711,7 @@ static int ibmvfc_send_event(struct ibmvfc_event *evt,
 				     be64_to_cpu(crq_as_u64[1]));
 
 	if (rc) {
+		atomic_set(&evt->active, 0);
 		list_del(&evt->queue_list);
 		spin_unlock_irqrestore(&evt->queue->l_lock, flags);
 		del_timer(&evt->timer);
@@ -1737,7 +1739,6 @@ static int ibmvfc_send_event(struct ibmvfc_event *evt,
 
 		evt->done(evt);
 	} else {
-		atomic_set(&evt->active, 1);
 		spin_unlock_irqrestore(&evt->queue->l_lock, flags);
 		ibmvfc_trc_start(evt);
 	}
-- 
2.31.1