This patch is based on an earlier one submitted
by Jon Maxwell with the following commit message:
"We recently encountered a bug where a few customers using ibmveth on the
same LPAR hit an issue where a TCP session hung when large receive was
enabled. Closer analysis revealed that the session was stuck because the
one side was advertising a zero window repeatedly.
We narrowed this down to the fact the ibmveth driver did not set gso_size
which is translated by TCP into the MSS later up the stack. The MSS is
used to calculate the TCP window size and as that was abnormally large,
it was calculating a zero window, even although the sockets receive buffer
was completely empty."
We rely on the Virtual I/O Server partition in a pseries
environment to provide the MSS through the TCP header checksum
field. The stipulation is that users should not disable checksum
offloading if rx packet aggregation is enabled through VIOS.
Some firmware offerings provide the MSS in the RX buffer.
This is signalled by a bit in the RX queue descriptor.
Reviewed-by: Brian King
Reviewed-by: Pradeep Satyanarayana
Reviewed-by: Marcelo Ricardo Leitner
Reviewed-by: Jonathan Maxwell
Reviewed-by: David Dai
Signed-off-by: Thomas Falcon
---
v3: include a check for non-zero mss when calculating gso_segs
v2: calculate gso_segs after Eric Dumazet's comments on the earlier patch
and make sure everyone is included on CC
---
drivers/net/ethernet/ibm/ibmveth.c | 72 --
drivers/net/ethernet/ibm/ibmveth.h | 1 +
2 files changed, 71 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/ibm/ibmveth.c
b/drivers/net/ethernet/ibm/ibmveth.c
index ebe6071..6dc24a1 100644
--- a/drivers/net/ethernet/ibm/ibmveth.c
+++ b/drivers/net/ethernet/ibm/ibmveth.c
@@ -58,7 +58,7 @@
static const char ibmveth_driver_name[] = "ibmveth";
static const char ibmveth_driver_string[] = "IBM Power Virtual Ethernet
Driver";
-#define ibmveth_driver_version "1.05"
+#define ibmveth_driver_version "1.06"
MODULE_AUTHOR("Santiago Leon ");
MODULE_DESCRIPTION("IBM Power Virtual Ethernet Driver");
@@ -137,6 +137,11 @@ static inline int ibmveth_rxq_frame_offset(struct
ibmveth_adapter *adapter)
return ibmveth_rxq_flags(adapter) & IBMVETH_RXQ_OFF_MASK;
}
+static inline int ibmveth_rxq_large_packet(struct ibmveth_adapter *adapter)
+{
+ return ibmveth_rxq_flags(adapter) & IBMVETH_RXQ_LRG_PKT;
+}
+
static inline int ibmveth_rxq_frame_length(struct ibmveth_adapter *adapter)
{
return
be32_to_cpu(adapter->rx_queue.queue_addr[adapter->rx_queue.index].length);
@@ -1174,6 +1179,52 @@ static netdev_tx_t ibmveth_start_xmit(struct sk_buff
*skb,
goto retry_bounce;
}
+static void ibmveth_rx_mss_helper(struct sk_buff *skb, u16 mss, int lrg_pkt)
+{
+ struct tcphdr *tcph;
+ int offset = 0;
+ int hdr_len;
+
+ /* only TCP packets will be aggregated */
+ if (skb->protocol == htons(ETH_P_IP)) {
+ struct iphdr *iph = (struct iphdr *)skb->data;
+
+ if (iph->protocol == IPPROTO_TCP) {
+ offset = iph->ihl * 4;
+ skb_shinfo(skb)->gso_type = SKB_GSO_TCPV4;
+ } else {
+ return;
+ }
+ } else if (skb->protocol == htons(ETH_P_IPV6)) {
+ struct ipv6hdr *iph6 = (struct ipv6hdr *)skb->data;
+
+ if (iph6->nexthdr == IPPROTO_TCP) {
+ offset = sizeof(struct ipv6hdr);
+ skb_shinfo(skb)->gso_type = SKB_GSO_TCPV6;
+ } else {
+ return;
+ }
+ } else {
+ return;
+ }
+ /* if mss is not set through Large Packet bit/mss in rx buffer,
+* expect that the mss will be written to the tcp header checksum.
+*/
+ tcph = (struct tcphdr *)(skb->data + offset);
+ hdr_len = offset + tcph->doff * 4;
+ if (lrg_pkt) {
+ skb_shinfo(skb)->gso_size = mss;
+ } else if (offset) {
+ skb_shinfo(skb)->gso_size = ntohs(tcph->check);
+ tcph->check = 0;
+ }
+
+ if (skb_shinfo(skb)->gso_size)
+ skb_shinfo(skb)->gso_segs =
+ DIV_ROUND_UP(skb->len - hdr_len,
+skb_shinfo(skb)->gso_size);
+}
+
static int ibmveth_poll(struct napi_struct *napi, int budget)
{
struct ibmveth_adapter *adapter =
@@ -1182,6 +1233,7 @@ static int ibmveth_poll(struct napi_struct *napi, int
budget)
int frames_processed = 0;
unsigned long lpar_rc;
struct iphdr *iph;
+ u16 mss = 0;
restart_poll:
while (frames_processed < budget) {
@@ -1199,9 +1251,21 @@ static int ibmveth_poll(struct napi_struct *napi, int
budget)
int length = ibmveth_rxq_frame_length(adapter);
int offset = ibmveth_rxq_frame_offset(ad
