[SRU,Bionic,1/3] vmxnet3: avoid xmit reset due to a race in vmxnet3

Message ID 9dfa9806f89752ea2f299c4bf6616a0a1d570998.1525385262.git.joseph.salisbury@canonical.com
State New
Headers show
Series
  • Fixes for LP:1768143
Related show

Commit Message

Joseph Salisbury June 1, 2018, 4:07 p.m.
From: Ronak Doshi <doshir@vmware.com>

BugLink: http://bugs.launchpad.net/bugs/1768143

The field txNumDeferred is used by the driver to keep track of the number
of packets it has pushed to the emulation. The driver increments it on
pushing the packet to the emulation and the emulation resets it to 0 at
the end of the transmit.

There is a possibility of a race either when (a) ESX is under heavy load or
(b) workload inside VM is of low packet rate.

This race results in xmit hangs when network coalescing is disabled. This
change creates a local copy of txNumDeferred and uses it to perform ring
arithmetic.

Reported-by: Noriho Tanaka <ntanaka@vmware.com>
Signed-off-by: Ronak Doshi <doshir@vmware.com>
Acked-by: Shrikrishna Khare <skhare@vmware.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
(back ported from commit 7a4c003d6921e2af215f4790aa43a292bdc78be0)
Signed-off-by: Joseph Salisbury <joseph.salisbury@canonical.com>
---
 drivers/net/vmxnet3/vmxnet3_drv.c | 13 ++++++++-----
 drivers/net/vmxnet3/vmxnet3_int.h |  4 ++--
 2 files changed, 10 insertions(+), 7 deletions(-)

Patch

diff --git a/drivers/net/vmxnet3/vmxnet3_drv.c b/drivers/net/vmxnet3/vmxnet3_drv.c
index cf95290..345e738 100644
--- a/drivers/net/vmxnet3/vmxnet3_drv.c
+++ b/drivers/net/vmxnet3/vmxnet3_drv.c
@@ -977,6 +977,8 @@  vmxnet3_tq_xmit(struct sk_buff *skb, struct vmxnet3_tx_queue *tq,
 {
 	int ret;
 	u32 count;
+	int num_pkts;
+	int tx_num_deferred;
 	unsigned long flags;
 	struct vmxnet3_tx_ctx ctx;
 	union Vmxnet3_GenericDesc *gdesc;
@@ -1075,12 +1077,12 @@  vmxnet3_tq_xmit(struct sk_buff *skb, struct vmxnet3_tx_queue *tq,
 #else
 	gdesc = ctx.sop_txd;
 #endif
+	tx_num_deferred = le32_to_cpu(tq->shared->txNumDeferred);
 	if (ctx.mss) {
 		gdesc->txd.hlen = ctx.eth_ip_hdr_size + ctx.l4_hdr_size;
 		gdesc->txd.om = VMXNET3_OM_TSO;
 		gdesc->txd.msscof = ctx.mss;
-		le32_add_cpu(&tq->shared->txNumDeferred, (skb->len -
-			     gdesc->txd.hlen + ctx.mss - 1) / ctx.mss);
+		num_pkts = (skb->len - gdesc->txd.hlen + ctx.mss - 1) / ctx.mss;
 	} else {
 		if (skb->ip_summed == CHECKSUM_PARTIAL) {
 			gdesc->txd.hlen = ctx.eth_ip_hdr_size;
@@ -1091,8 +1093,10 @@  vmxnet3_tq_xmit(struct sk_buff *skb, struct vmxnet3_tx_queue *tq,
 			gdesc->txd.om = 0;
 			gdesc->txd.msscof = 0;
 		}
-		le32_add_cpu(&tq->shared->txNumDeferred, 1);
+		num_pkts = 1;
 	}
+	le32_add_cpu(&tq->shared->txNumDeferred, num_pkts);
+	tx_num_deferred += num_pkts;
 
 	if (skb_vlan_tag_present(skb)) {
 		gdesc->txd.ti = 1;
@@ -1118,8 +1122,7 @@  vmxnet3_tq_xmit(struct sk_buff *skb, struct vmxnet3_tx_queue *tq,
 
 	spin_unlock_irqrestore(&tq->tx_lock, flags);
 
-	if (le32_to_cpu(tq->shared->txNumDeferred) >=
-					le32_to_cpu(tq->shared->txThreshold)) {
+	if (tx_num_deferred >= le32_to_cpu(tq->shared->txThreshold)) {
 		tq->shared->txNumDeferred = 0;
 		VMXNET3_WRITE_BAR0_REG(adapter,
 				       VMXNET3_REG_TXPROD + tq->qid * 8,
diff --git a/drivers/net/vmxnet3/vmxnet3_int.h b/drivers/net/vmxnet3/vmxnet3_int.h
index 9c51b8b..dc7e141 100644
--- a/drivers/net/vmxnet3/vmxnet3_int.h
+++ b/drivers/net/vmxnet3/vmxnet3_int.h
@@ -69,10 +69,10 @@ 
 /*
  * Version numbers
  */
-#define VMXNET3_DRIVER_VERSION_STRING   "1.4.a.0-k"
+#define VMXNET3_DRIVER_VERSION_STRING   "1.4.12.0-k"
 
 /* a 32-bit int, each byte encode a verion number in VMXNET3_DRIVER_VERSION */
-#define VMXNET3_DRIVER_VERSION_NUM      0x01040a00
+#define VMXNET3_DRIVER_VERSION_NUM      0x01040c00
 
 #if defined(CONFIG_PCI_MSI)
 	/* RSS only makes sense if MSI-X is supported. */