| Message ID | 20211029220316.2003519-1-sukadev@linux.ibm.com (mailing list archive) |
|---|---|
| State | Accepted |
| Commit | 8878e46fcfd46b19964bd90e13b25dd94cbfc9be |
| Delegated to: | Netdev Maintainers |
| Headers | show |
| Series | [net,1/3] ibmvnic: don't stop queue in xmit | expand |
On 2021-10-29 15:03, Sukadev Bhattiprolu wrote: > 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>
Hello: This series was applied to netdev/net.git (master) by David S. Miller <davem@davemloft.net>: On Fri, 29 Oct 2021 15:03:14 -0700 you wrote: > 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. > > [...] Here is the summary with links: - [net,1/3] ibmvnic: don't stop queue in xmit https://git.kernel.org/netdev/net/c/8878e46fcfd4 - [net,2/3] ibmvnic: Process crqs after enabling interrupts https://git.kernel.org/netdev/net/c/6e20d00158f3 - [net,3/3] ibmvnic: delay complete() https://git.kernel.org/netdev/net/c/6b278c0cb378 You are awesome, thank you!
diff --git a/drivers/net/ethernet/ibm/ibmvnic.c b/drivers/net/ethernet/ibm/ibmvnic.c index 8f17096e614d..a1533979c670 100644 --- a/drivers/net/ethernet/ibm/ibmvnic.c +++ b/drivers/net/ethernet/ibm/ibmvnic.c @@ -1914,8 +1914,6 @@ static netdev_tx_t ibmvnic_xmit(struct sk_buff *skb, struct net_device *netdev) ind_bufp = &tx_scrq->ind_buf; 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++;
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> --- drivers/net/ethernet/ibm/ibmvnic.c | 2 -- 1 file changed, 2 deletions(-)