vmxnet3: use correct flag to indicate LRO feature

'Commit 45dac1d ("vmxnet3: Changes for vmxnet3 adapter version 2
(fwd)")' introduced a flag "lro" in structure vmxnet3_adapter which is
used to indicate whether LRO is enabled or not. However, the patch
did not set the flag and hence it was never exercised.

So, when LRO is enabled, it resulted in poor TCP performance due to
delayed acks. This issue is seen with packets which are larger than
the mss getting a delayed ack rather than an immediate ack, thus
resulting in high latency.

This patch removes the lro flag and directly uses device features
against NETIF_F_LRO to check if lro is enabled.

Fixes: 45dac1d ("vmxnet3: Changes for vmxnet3 adapter version 2 (fwd)")
Reported-by: Rachel Lunnon <[email protected]>
Signed-off-by: Ronak Doshi <[email protected]>
Acked-by: Shrikrishna Khare <[email protected]>
Signed-off-by: David S. Miller <[email protected]>

Author: Ronak Doshi

drivers/net/vmxnet3/vmxnet3_drv.c

@@ -1473,7 +1473,8 @@ vmxnet3_rq_rx_complete(struct vmxnet3_rx_queue *rq,
 			vmxnet3_rx_csum(adapter, skb,
 					(union Vmxnet3_GenericDesc *)rcd);
 			skb->protocol = eth_type_trans(skb, adapter->netdev);
-			if (!rcd->tcp || !adapter->lro)
+			if (!rcd->tcp ||
+			    !(adapter->netdev->features & NETIF_F_LRO))
 				goto not_lro;
 
 			if (segCnt != 0 && mss != 0) {

drivers/net/vmxnet3/vmxnet3_int.h

@@ -69,10 +69,10 @@
 /*
  * Version numbers
  */
-#define VMXNET3_DRIVER_VERSION_STRING   "1.4.12.0-k"
+#define VMXNET3_DRIVER_VERSION_STRING   "1.4.13.0-k"
 
 /* a 32-bit int, each byte encode a verion number in VMXNET3_DRIVER_VERSION */
-#define VMXNET3_DRIVER_VERSION_NUM      0x01040c00
+#define VMXNET3_DRIVER_VERSION_NUM      0x01040d00
 
 #if defined(CONFIG_PCI_MSI)
 	/* RSS only makes sense if MSI-X is supported. */
@@ -343,7 +343,6 @@ struct vmxnet3_adapter {
 	u8                              version;
 
 	bool				rxcsum;
-	bool				lro;
 
 #ifdef VMXNET3_RSS
 	struct UPT1_RSSConf		*rss_conf;