[TG3]: Add TSO workaround using GSO
Use GSO to workaround a rare TSO bug on some chips. This hardware
bug may be triggered when the TSO header size is greater than 80
bytes. When this condition is detected in a TSO packet, the driver
will use GSO to segment the packet to workaround the hardware bug.
Thanks to Juergen Kreileder <jk@blackdown.de> for reporting the
problem and collecting traces to help debug the problem.
And thanks to Herbert Xu <herbert@gondor.apana.org.au> for providing
the GSO mechanism that happens to be the perfect workaround for this
problem.
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/tg3.c b/drivers/net/tg3.c
index 2c36e70..63d4b2c 100644
--- a/drivers/net/tg3.c
+++ b/drivers/net/tg3.c
@@ -3880,6 +3880,40 @@
return NETDEV_TX_OK;
}
+#if TG3_TSO_SUPPORT != 0
+static int tg3_start_xmit_dma_bug(struct sk_buff *, struct net_device *);
+
+/* Use GSO to workaround a rare TSO bug that may be triggered when the
+ * TSO header is greater than 80 bytes.
+ */
+static int tg3_tso_bug(struct tg3 *tp, struct sk_buff *skb)
+{
+ struct sk_buff *segs, *nskb;
+
+ /* Estimate the number of fragments in the worst case */
+ if (unlikely(TX_BUFFS_AVAIL(tp) <= (skb_shinfo(skb)->gso_segs * 3))) {
+ netif_stop_queue(tp->dev);
+ return NETDEV_TX_BUSY;
+ }
+
+ segs = skb_gso_segment(skb, tp->dev->features & ~NETIF_F_TSO);
+ if (unlikely(IS_ERR(segs)))
+ goto tg3_tso_bug_end;
+
+ do {
+ nskb = segs;
+ segs = segs->next;
+ nskb->next = NULL;
+ tg3_start_xmit_dma_bug(nskb, tp->dev);
+ } while (segs);
+
+tg3_tso_bug_end:
+ dev_kfree_skb(skb);
+
+ return NETDEV_TX_OK;
+}
+#endif
+
/* hard_start_xmit for devices that have the 4G bug and/or 40-bit bug and
* support TG3_FLG2_HW_TSO_1 or firmware TSO only.
*/
@@ -3916,7 +3950,7 @@
mss = 0;
if (skb->len > (tp->dev->mtu + ETH_HLEN) &&
(mss = skb_shinfo(skb)->gso_size) != 0) {
- int tcp_opt_len, ip_tcp_len;
+ int tcp_opt_len, ip_tcp_len, hdr_len;
if (skb_header_cloned(skb) &&
pskb_expand_head(skb, 0, 0, GFP_ATOMIC)) {
@@ -3927,11 +3961,16 @@
tcp_opt_len = ((skb->h.th->doff - 5) * 4);
ip_tcp_len = (skb->nh.iph->ihl * 4) + sizeof(struct tcphdr);
+ hdr_len = ip_tcp_len + tcp_opt_len;
+ if (unlikely((ETH_HLEN + hdr_len) > 80) &&
+ (tp->tg3_flags2 & TG3_FLG2_HW_TSO_1_BUG))
+ return (tg3_tso_bug(tp, skb));
+
base_flags |= (TXD_FLAG_CPU_PRE_DMA |
TXD_FLAG_CPU_POST_DMA);
skb->nh.iph->check = 0;
- skb->nh.iph->tot_len = htons(mss + ip_tcp_len + tcp_opt_len);
+ skb->nh.iph->tot_len = htons(mss + hdr_len);
if (tp->tg3_flags2 & TG3_FLG2_HW_TSO) {
skb->h.th->check = 0;
base_flags &= ~TXD_FLAG_TCPUDP_CSUM;
@@ -10192,8 +10231,14 @@
GET_ASIC_REV(tp->pci_chip_rev_id) == ASIC_REV_5787) {
tp->tg3_flags2 |= TG3_FLG2_HW_TSO_2;
tp->tg3_flags2 |= TG3_FLG2_1SHOT_MSI;
- } else
- tp->tg3_flags2 |= TG3_FLG2_HW_TSO_1;
+ } else {
+ tp->tg3_flags2 |= TG3_FLG2_HW_TSO_1 |
+ TG3_FLG2_HW_TSO_1_BUG;
+ if (GET_ASIC_REV(tp->pci_chip_rev_id) ==
+ ASIC_REV_5750 &&
+ tp->pci_chip_rev_id >= CHIPREV_ID_5750_C2)
+ tp->tg3_flags2 &= ~TG3_FLG2_HW_TSO_1_BUG;
+ }
}
if (GET_ASIC_REV(tp->pci_chip_rev_id) != ASIC_REV_5705 &&