From 41f714672f93608751dbd2fa2291d476a8ff0150 Mon Sep 17 00:00:00 2001
From: Thomas Falcon <tlfalcon@linux.vnet.ibm.com>
Date: Fri, 6 Apr 2018 18:37:03 -0500
Subject: [PATCH] ibmvnic: Zero used TX descriptor counter on reset

References: bsc#1088600
Patch-mainline: v4.17-rc1
Git-commit: 41f714672f93608751dbd2fa2291d476a8ff0150

The counter that tracks used TX descriptors pending completion
needs to be zeroed as part of a device reset. This change fixes
a bug causing transmit queues to be stopped unnecessarily and in
some cases a transmit queue stall and timeout reset. If the counter
is not reset, the remaining descriptors will not be "removed",
effectively reducing queue capacity. If the queue is over half full,
it will cause the queue to stall if stopped.

Signed-off-by: Thomas Falcon <tlfalcon@linux.vnet.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
 drivers/net/ethernet/ibm/ibmvnic.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
index 58e01432c2aa..153a868c5135 100644
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -2361,6 +2361,7 @@ static int reset_one_sub_crq_queue(struct ibmvnic_adapter *adapter,
 	}
 
 	memset(scrq->msgs, 0, 4 * PAGE_SIZE);
+	atomic_set(&scrq->used, 0);
 	scrq->cur = 0;
 
 	rc = h_reg_sub_crq(adapter->vdev->unit_address, scrq->msg_token,
-- 
2.13.6