vmxnet3: use gro callback when UPT is enabled

Currently, vmxnet3 uses GRO callback only if LRO is disabled. However,
on smartNic based setups where UPT is supported, LRO can be enabled
from guest VM but UPT devicve does not support LRO as of now. In such
cases, there can be performance degradation as GRO is not being done.

This patch fixes this issue by calling GRO API when UPT is enabled. We
use updateRxProd to determine if UPT mode is active or not.

To clarify few things discussed over the thread:
The patch is not neglecting any feature bits nor disabling GRO. It uses
GRO callback when UPT is active as LRO is not available in UPT.
GRO callback cannot be used as default for all cases as it degrades
performance for non-UPT cases or for cases when LRO is already done in
ESXi.

Cc: stable@vger.kernel.org
Fixes: 6f91f4ba046e ("vmxnet3: add support for capability registers")
Signed-off-by: Ronak Doshi <doshir@vmware.com>
Reviewed-by: Simon Horman <simon.horman@corigine.com>
Link: https://lore.kernel.org/r/20230323200721.27622-1-doshir@vmware.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

diff --git a/drivers/net/vmxnet3/vmxnet3_drv.c b/drivers/net/vmxnet3/vmxnet3_drv.c
index 682987040ea821e74d2d732a77d93d546f803006..da488cbb05428c040fc97e74c86302be39bee4ab 100644 (file)
--- a/drivers/net/vmxnet3/vmxnet3_drv.c
+++ b/drivers/net/vmxnet3/vmxnet3_drv.c
@@ -1688,7 +1688,9 @@ not_lro:
                        if (unlikely(rcd->ts))
                                __vlan_hwaccel_put_tag(skb, htons(ETH_P_8021Q), rcd->tci);
 
-                       if (adapter->netdev->features & NETIF_F_LRO)
+                       /* Use GRO callback if UPT is enabled */
+                       if ((adapter->netdev->features & NETIF_F_LRO) &&
+                           !rq->shared->updateRxProd)
                                netif_receive_skb(skb);
                        else
                                napi_gro_receive(&rq->napi, skb);