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[TG3]: Fix 4GB boundary tx handling

Browse source 
Fix and simplify the workaround code for the 4GB boundary tx buffer
hardware bug.

1. Need to unmap the original SKB's dma addresses if a new SKB cannot
   be allocated.

2. Need to pass the base flag to tigon3_4gb_hwbug_workaround() or TSO
   won't work properly.

3. The guilty entry and length parameters for
   tigon3_4gb_hwbug_workaround() are removed as they are not necessary.

4. Remove assumption that only one fragment can hit the 4GB boundary.
   Another fragment can hit 8GB for example.

Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Michael Chan 2005-09-17 00:46:27 -07:00 committed by David S. Miller
parent eb8edb0857
commit c58ec93245
1 changed files with 39 additions and 55 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

94
drivers/net/tg3.c
View file

@ -3442,31 +3442,47 @@ static void tg3_tx_timeout(struct net_device *dev)
schedule_work(&tp->reset_task);
}
/* Test for DMA buffers crossing any 4GB boundaries: 4G, 8G, etc */
static inline int tg3_4g_overflow_test(dma_addr_t mapping, int len)
{
u32 base = (u32) mapping & 0xffffffff;
return ((base > 0xffffdcc0) &&
(base + len + 8 < base));
}
static void tg3_set_txd(struct tg3 *, int, dma_addr_t, int, u32, u32);
static int tigon3_4gb_hwbug_workaround(struct tg3 *tp, struct sk_buff *skb,
u32 guilty_entry, int guilty_len,
u32 last_plus_one, u32 *start, u32 mss)
u32 last_plus_one, u32 *start,
u32 base_flags, u32 mss)
{
struct sk_buff *new_skb = skb_copy(skb, GFP_ATOMIC);
dma_addr_t new_addr;
dma_addr_t new_addr = 0;
u32 entry = *start;
int i;
int i, ret = 0;
if (!new_skb) {
dev_kfree_skb(skb);
return -1;
ret = -1;
} else {
/* New SKB is guaranteed to be linear. */
entry = *start;
new_addr = pci_map_single(tp->pdev, new_skb->data, new_skb->len,
PCI_DMA_TODEVICE);
/* Make sure new skb does not cross any 4G boundaries.
* Drop the packet if it does.
*/
if (tg3_4g_overflow_test(new_addr, new_skb->len)) {
ret = -1;
dev_kfree_skb(new_skb);
new_skb = NULL;
} else {
tg3_set_txd(tp, entry, new_addr, new_skb->len,
base_flags, 1 | (mss << 1));
*start = NEXT_TX(entry);
}
}
/* New SKB is guaranteed to be linear. */
entry = *start;
new_addr = pci_map_single(tp->pdev, new_skb->data, new_skb->len,
PCI_DMA_TODEVICE);
tg3_set_txd(tp, entry, new_addr, new_skb->len,
(skb->ip_summed == CHECKSUM_HW) ?
TXD_FLAG_TCPUDP_CSUM : 0, 1 | (mss << 1));
*start = NEXT_TX(entry);
/* Now clean up the sw ring entries. */
i = 0;
while (entry != last_plus_one) {
@ -3491,7 +3507,7 @@ static int tigon3_4gb_hwbug_workaround(struct tg3 *tp, struct sk_buff *skb,
dev_kfree_skb(skb);
return 0;
return ret;
}
static void tg3_set_txd(struct tg3 *tp, int entry,
@ -3517,19 +3533,10 @@ static void tg3_set_txd(struct tg3 *tp, int entry,
txd->vlan_tag = vlan_tag << TXD_VLAN_TAG_SHIFT;
}
static inline int tg3_4g_overflow_test(dma_addr_t mapping, int len)
{
u32 base = (u32) mapping & 0xffffffff;
return ((base > 0xffffdcc0) &&
(base + len + 8 < base));
}
static int tg3_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct tg3 *tp = netdev_priv(dev);
dma_addr_t mapping;
unsigned int i;
u32 len, entry, base_flags, mss;
int would_hit_hwbug;
@ -3624,7 +3631,7 @@ static int tg3_start_xmit(struct sk_buff *skb, struct net_device *dev)
would_hit_hwbug = 0;
if (tg3_4g_overflow_test(mapping, len))
would_hit_hwbug = entry + 1;
would_hit_hwbug = 1;
tg3_set_txd(tp, entry, mapping, len, base_flags,
(skb_shinfo(skb)->nr_frags == 0) | (mss << 1));
@ -3648,12 +3655,8 @@ static int tg3_start_xmit(struct sk_buff *skb, struct net_device *dev)
tp->tx_buffers[entry].skb = NULL;
pci_unmap_addr_set(&tp->tx_buffers[entry], mapping, mapping);
if (tg3_4g_overflow_test(mapping, len)) {
/* Only one should match. */
if (would_hit_hwbug)
BUG();
would_hit_hwbug = entry + 1;
}
if (tg3_4g_overflow_test(mapping, len))
would_hit_hwbug = 1;
if (tp->tg3_flags2 & TG3_FLG2_HW_TSO)
tg3_set_txd(tp, entry, mapping, len,
@ -3669,34 +3672,15 @@ static int tg3_start_xmit(struct sk_buff *skb, struct net_device *dev)
if (would_hit_hwbug) {
u32 last_plus_one = entry;
u32 start;
unsigned int len = 0;
would_hit_hwbug -= 1;
entry = entry - 1 - skb_shinfo(skb)->nr_frags;
entry &= (TG3_TX_RING_SIZE - 1);
start = entry;
i = 0;
while (entry != last_plus_one) {
if (i == 0)
len = skb_headlen(skb);
else
len = skb_shinfo(skb)->frags[i-1].size;
if (entry == would_hit_hwbug)
break;
i++;
entry = NEXT_TX(entry);
}
start = entry - 1 - skb_shinfo(skb)->nr_frags;
start &= (TG3_TX_RING_SIZE - 1);
/* If the workaround fails due to memory/mapping
* failure, silently drop this packet.
*/
if (tigon3_4gb_hwbug_workaround(tp, skb,
entry, len,
last_plus_one,
&start, mss))
if (tigon3_4gb_hwbug_workaround(tp, skb, last_plus_one,
&start, base_flags, mss))
goto out_unlock;
entry = start;