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[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>
This commit is contained in:
Michael Chan 2006-06-29 20:15:54 -07:00 committed by David S. Miller
parent 1661394e78
commit 52c0fd834e
2 changed files with 51 additions and 5 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

53
drivers/net/tg3.c
View File

@ -3880,6 +3880,40 @@ static int tg3_start_xmit(struct sk_buff *skb, struct net_device *dev)
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 @@ static int tg3_start_xmit_dma_bug(struct sk_buff *skb, struct net_device *dev)
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 @@ static int tg3_start_xmit_dma_bug(struct sk_buff *skb, struct net_device *dev)
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 @@ static int __devinit tg3_get_invariants(struct tg3 *tp)
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 &&

3
drivers/net/tg3.h
View File

@ -125,6 +125,7 @@
#define CHIPREV_ID_5750_A0 0x4000
#define CHIPREV_ID_5750_A1 0x4001
#define CHIPREV_ID_5750_A3 0x4003
#define CHIPREV_ID_5750_C2 0x4202
#define CHIPREV_ID_5752_A0_HW 0x5000
#define CHIPREV_ID_5752_A0 0x6000
#define CHIPREV_ID_5752_A1 0x6001
@ -2193,7 +2194,7 @@ struct tg3 {
#define TG3_FLAG_INIT_COMPLETE 0x80000000
u32 tg3_flags2;
#define TG3_FLG2_RESTART_TIMER 0x00000001
/* 0x00000002 available */
#define TG3_FLG2_HW_TSO_1_BUG 0x00000002
#define TG3_FLG2_NO_ETH_WIRE_SPEED 0x00000004
#define TG3_FLG2_IS_5788 0x00000008
#define TG3_FLG2_MAX_RXPEND_64 0x00000010