Skip to content

Commit

Permalink
tg3: Cleanup transmit error path
Browse files Browse the repository at this point in the history 
This patch consolidates the skb cleanup code into a function named
tg3_skb_error_unmap().  The modification addresses a long-standing bug
where pci_unmap_single() was incorrectly being called instead of
pci_unmap_page() in tigon3_dma_hwbug_workaround().

Signed-off-by: Matt Carlson <mcarlson@broadcom.com>
Reviewed-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
  • Loading branch information
Matt Carlson authored and David S. Miller committed May 19, 2011
1 parent 2ffcc98 commit 432aa7e
Showing 1 changed file with 38 additions and 60 deletions.
98 changes: 38 additions & 60 deletions drivers/net/tg3.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -5758,16 +5758,39 @@ static void tg3_set_txd(struct tg3_napi *tnapi, int entry,
txd->vlan_tag = vlan_tag << TXD_VLAN_TAG_SHIFT;
}

static void tg3_skb_error_unmap(struct tg3_napi *tnapi,
struct sk_buff *skb, int last)
{
int i;
u32 entry = tnapi->tx_prod;
struct ring_info *txb = &tnapi->tx_buffers[entry];

pci_unmap_single(tnapi->tp->pdev,
dma_unmap_addr(txb, mapping),
skb_headlen(skb),
PCI_DMA_TODEVICE);
for (i = 0; i <= last; i++) {
skb_frag_t *frag = &skb_shinfo(skb)->frags[i];

entry = NEXT_TX(entry);
txb = &tnapi->tx_buffers[entry];

pci_unmap_page(tnapi->tp->pdev,
dma_unmap_addr(txb, mapping),
frag->size, PCI_DMA_TODEVICE);
}
}

/* Workaround 4GB and 40-bit hardware DMA bugs. */
static int tigon3_dma_hwbug_workaround(struct tg3_napi *tnapi,
struct sk_buff *skb, u32 last_plus_one,
u32 *start, u32 base_flags, u32 mss)
struct sk_buff *skb,
u32 base_flags, u32 mss)
{
struct tg3 *tp = tnapi->tp;
struct sk_buff *new_skb;
dma_addr_t new_addr = 0;
u32 entry = *start;
int i, ret = 0;
u32 entry = tnapi->tx_prod;
int ret = 0;

if (GET_ASIC_REV(tp->pci_chip_rev_id) != ASIC_REV_5701)
new_skb = skb_copy(skb, GFP_ATOMIC);
Expand All @@ -5783,14 +5806,12 @@ static int tigon3_dma_hwbug_workaround(struct tg3_napi *tnapi,
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 the mapping succeeded */
if (pci_dma_mapping_error(tp->pdev, new_addr)) {
ret = -1;
dev_kfree_skb(new_skb);
new_skb = NULL;

/* Make sure new skb does not cross any 4G boundaries.
* Drop the packet if it does.
Expand All @@ -5801,39 +5822,16 @@ static int tigon3_dma_hwbug_workaround(struct tg3_napi *tnapi,
PCI_DMA_TODEVICE);
ret = -1;
dev_kfree_skb(new_skb);
new_skb = NULL;
} else {
tnapi->tx_buffers[entry].skb = new_skb;
dma_unmap_addr_set(&tnapi->tx_buffers[entry],
mapping, new_addr);

tg3_set_txd(tnapi, entry, new_addr, new_skb->len,
base_flags, 1 | (mss << 1));
*start = NEXT_TX(entry);
}
}

/* Now clean up the sw ring entries. */
i = 0;
while (entry != last_plus_one) {
int len;

if (i == 0)
len = skb_headlen(skb);
else
len = skb_shinfo(skb)->frags[i-1].size;

pci_unmap_single(tp->pdev,
dma_unmap_addr(&tnapi->tx_buffers[entry],
mapping),
len, PCI_DMA_TODEVICE);
if (i == 0) {
tnapi->tx_buffers[entry].skb = new_skb;
dma_unmap_addr_set(&tnapi->tx_buffers[entry], mapping,
new_addr);
} else {
tnapi->tx_buffers[entry].skb = NULL;
}
entry = NEXT_TX(entry);
i++;
}

dev_kfree_skb(skb);

return ret;
Expand Down Expand Up @@ -5889,11 +5887,11 @@ static netdev_tx_t tg3_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct tg3 *tp = netdev_priv(dev);
u32 len, entry, base_flags, mss;
int would_hit_hwbug;
int i = -1, would_hit_hwbug;
dma_addr_t mapping;
struct tg3_napi *tnapi;
struct netdev_queue *txq;
unsigned int i, last;
unsigned int last;

txq = netdev_get_tx_queue(dev, skb_get_queue_mapping(skb));
tnapi = &tp->napi[skb_get_queue_mapping(skb)];
Expand Down Expand Up @@ -6074,20 +6072,15 @@ static netdev_tx_t tg3_start_xmit(struct sk_buff *skb, struct net_device *dev)
}

if (would_hit_hwbug) {
u32 last_plus_one = entry;
u32 start;

start = entry - 1 - skb_shinfo(skb)->nr_frags;
start &= (TG3_TX_RING_SIZE - 1);
tg3_skb_error_unmap(tnapi, skb, i);

/* If the workaround fails due to memory/mapping
* failure, silently drop this packet.
*/
if (tigon3_dma_hwbug_workaround(tnapi, skb, last_plus_one,
&start, base_flags, mss))
if (tigon3_dma_hwbug_workaround(tnapi, skb, base_flags, mss))
goto out_unlock;

entry = start;
entry = NEXT_TX(tnapi->tx_prod);
}

/* Packets are ready, update Tx producer idx local and on card. */
Expand All @@ -6113,24 +6106,9 @@ static netdev_tx_t tg3_start_xmit(struct sk_buff *skb, struct net_device *dev)
return NETDEV_TX_OK;

dma_error:
last = i;
entry = tnapi->tx_prod;
tnapi->tx_buffers[entry].skb = NULL;
pci_unmap_single(tp->pdev,
dma_unmap_addr(&tnapi->tx_buffers[entry], mapping),
skb_headlen(skb),
PCI_DMA_TODEVICE);
for (i = 0; i <= last; i++) {
skb_frag_t *frag = &skb_shinfo(skb)->frags[i];
entry = NEXT_TX(entry);

pci_unmap_page(tp->pdev,
dma_unmap_addr(&tnapi->tx_buffers[entry],
mapping),
frag->size, PCI_DMA_TODEVICE);
}

tg3_skb_error_unmap(tnapi, skb, i);
dev_kfree_skb(skb);
tnapi->tx_buffers[tnapi->tx_prod].skb = NULL;
return NETDEV_TX_OK;
}

Expand Down

0 comments on commit 432aa7e

Please sign in to comment.