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vmxnet3: use correct flag to indicate LRO feature

PATCH Applied Ronak Doshi 2 participants 2 messages Mar 16, 2018 – Mar 18, 2018

Subsystems (3)
Networking Network drivers VMware VMXNET3 Ethernet driver
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Ronak Doshi

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#0 lore raw

PATCH v2 2/2 vmxnet3: use correct flag to indicate LRO feature

'Commit 45dac1d6ea04 ("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 45dac1d6ea04 ("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]>

---
Changes in v2:
- Added "Fixes:" tag for the commit which introduced this issue

 drivers/net/vmxnet3/vmxnet3_drv.c | 3 ++-
 drivers/net/vmxnet3/vmxnet3_int.h | 5 ++---
 2 files changed, 4 insertions(+), 4 deletions(-)
drivers/net/vmxnet3/vmxnet3_drv.c +2 -1
index b466a422b72d..e04937f44f33 100644
@@ -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 +2 -3
index b94fdfd0b6f1..99387a4a20a8 100644
@@ -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;
Signature · 1 line
2.11.0
maintainer Applied
#1 lore raw

From: Ronak Doshi <[email protected]>
Date: Fri, 16 Mar 2018 14:49:19 -0700

Quoted 10 lines

'Commit 45dac1d6ea04 ("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.

Quoted 7 lines

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

Fixes 45dac1d6ea04 ("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]>

Applied.