From 8878e46fcfd46b19964bd90e13b25dd94cbfc9be Mon Sep 17 00:00:00 2001
From: Sukadev Bhattiprolu <sukadev@linux.ibm.com>
Date: Fri, 29 Oct 2021 15:03:14 -0700
Subject: [PATCH] ibmvnic: don't stop queue in xmit
References: bsc#1192273 ltc#194629 bsc#1191428 ltc#193985
Patch-mainline: v5.16-rc1
Git-commit: 8878e46fcfd46b19964bd90e13b25dd94cbfc9be
If adapter's resetting bit is on, discard the packet but don't stop the
transmit queue - instead leave that to the reset code. With this change,
it is possible that we may get several calls to ibmvnic_xmit() that simply
discard packets and return.
But if we stop the queue here, we might end up doing so just after
__ibmvnic_open() started the queues (during a hard/soft reset) and before
the ->resetting bit was cleared. If that happens, there will be no one to
restart queue and transmissions will be blocked indefinitely.
This can cause a TIMEOUT reset and with auto priority failover enabled,
an unnecessary FAILOVER reset to less favored backing device and then a
FAILOVER back to the most favored backing device. If we hit the window
repeatedly, we can get stuck in a loop of TIMEOUT, FAILOVER, FAILOVER
resets leaving the adapter unusable for extended periods of time.
Fixes: 7f5b030830fe ("ibmvnic: Free skb's in cases of failure in transmit")
Reported-by: Abdul Haleem <abdhalee@in.ibm.com>
Reported-by: Vaishnavi Bhat <vaish123@in.ibm.com>
Signed-off-by: Sukadev Bhattiprolu <sukadev@linux.ibm.com>
Reviewed-by: Dany Madden <drt@linux.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Acked-by: Michal Suchanek <msuchanek@suse.de>
---
drivers/net/ethernet/ibm/ibmvnic.c | 2 --
1 file changed, 2 deletions(-)
diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c
--- a/drivers/net/ethernet/ibm/ibmvnic.c
+++ b/drivers/net/ethernet/ibm/ibmvnic.c
@@ -1724,8 +1724,6 @@ static netdev_tx_t ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev)
netdev_tx_t ret = NETDEV_TX_OK;
if (test_bit(0, &adapter->resetting)) {
- if (!netif_subqueue_stopped(netdev, skb))
- netif_stop_subqueue(netdev, queue_num);
dev_kfree_skb_any(skb);
tx_send_failed++;
--
2.31.1