From c58ec93245a1fb7354f9e331960380827b9f41db Mon Sep 17 00:00:00 2001 From: Michael Chan Date: Sat, 17 Sep 2005 00:46:27 -0700 Subject: [PATCH] [TG3]: Fix 4GB boundary tx handling 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 Signed-off-by: David S. Miller --- drivers/net/tg3.c | 94 +++++++++++++++++++++++-------------------------------- 1 file changed, 39 insertions(+), 55 deletions(-) diff --git a/drivers/net/tg3.c b/drivers/net/tg3.c index 06b02c59d90b..81f4aedf534c 100644 --- a/drivers/net/tg3.c +++ b/drivers/net/tg3.c @@ -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; -- 2.11.0