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net/mlx4_en: Use local var in tx flow for skb_shinfo(skb)
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Acces skb_shinfo(skb) once in tx flow.
Also, rename @i variable to @i_frag to avoid confusion, as the "goto
tx_drop_unmap;" relied on this @i variable.

Signed-off-by: Eric Dumazet <edumazet@google.com>
Signed-off-by: Amir Vadai <amirv@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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Eric Dumazet authored and David S. Miller committed Oct 6, 2014
1 parent f905c79 commit b9d8839
Showing 1 changed file with 34 additions and 24 deletions.
58 changes: 34 additions & 24 deletions drivers/net/ethernet/mellanox/mlx4/en_tx.c
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Original file line number Diff line number Diff line change
Expand Up @@ -532,21 +532,22 @@ static struct mlx4_en_tx_desc *mlx4_en_bounce_to_desc(struct mlx4_en_priv *priv,
}

static bool is_inline(int inline_thold, const struct sk_buff *skb,
const struct skb_shared_info *shinfo,
void **pfrag)
{
void *ptr;

if (inline_thold && !skb_is_gso(skb) && skb->len <= inline_thold) {
if (skb_shinfo(skb)->nr_frags == 1) {
ptr = skb_frag_address_safe(&skb_shinfo(skb)->frags[0]);
if (shinfo->nr_frags == 1) {
ptr = skb_frag_address_safe(&shinfo->frags[0]);
if (unlikely(!ptr))
return 0;

if (pfrag)
*pfrag = ptr;

return 1;
} else if (unlikely(skb_shinfo(skb)->nr_frags))
} else if (unlikely(shinfo->nr_frags))
return 0;
else
return 1;
Expand All @@ -567,18 +568,19 @@ static int inline_size(const struct sk_buff *skb)
}

static int get_real_size(const struct sk_buff *skb,
const struct skb_shared_info *shinfo,
struct net_device *dev,
int *lso_header_size)
{
struct mlx4_en_priv *priv = netdev_priv(dev);
int real_size;

if (skb_is_gso(skb)) {
if (shinfo->gso_size) {
if (skb->encapsulation)
*lso_header_size = (skb_inner_transport_header(skb) - skb->data) + inner_tcp_hdrlen(skb);
else
*lso_header_size = skb_transport_offset(skb) + tcp_hdrlen(skb);
real_size = CTRL_SIZE + skb_shinfo(skb)->nr_frags * DS_SIZE +
real_size = CTRL_SIZE + shinfo->nr_frags * DS_SIZE +
ALIGN(*lso_header_size + 4, DS_SIZE);
if (unlikely(*lso_header_size != skb_headlen(skb))) {
/* We add a segment for the skb linear buffer only if
Expand All @@ -593,8 +595,8 @@ static int get_real_size(const struct sk_buff *skb,
}
} else {
*lso_header_size = 0;
if (!is_inline(priv->prof->inline_thold, skb, NULL))
real_size = CTRL_SIZE + (skb_shinfo(skb)->nr_frags + 1) * DS_SIZE;
if (!is_inline(priv->prof->inline_thold, skb, shinfo, NULL))
real_size = CTRL_SIZE + (shinfo->nr_frags + 1) * DS_SIZE;
else
real_size = inline_size(skb);
}
Expand All @@ -604,6 +606,7 @@ static int get_real_size(const struct sk_buff *skb,

static void build_inline_wqe(struct mlx4_en_tx_desc *tx_desc,
const struct sk_buff *skb,
const struct skb_shared_info *shinfo,
int real_size, u16 *vlan_tag,
int tx_ind, void *fragptr)
{
Expand All @@ -619,9 +622,9 @@ static void build_inline_wqe(struct mlx4_en_tx_desc *tx_desc,
MIN_PKT_LEN - skb->len);
}
skb_copy_from_linear_data(skb, inl + 1, skb_headlen(skb));
if (skb_shinfo(skb)->nr_frags)
if (shinfo->nr_frags)
memcpy(((void *)(inl + 1)) + skb_headlen(skb), fragptr,
skb_frag_size(&skb_shinfo(skb)->frags[0]));
skb_frag_size(&shinfo->frags[0]));

} else {
inl->byte_count = cpu_to_be32(1 << 31 | spc);
Expand All @@ -639,9 +642,10 @@ static void build_inline_wqe(struct mlx4_en_tx_desc *tx_desc,
inl = (void *) (inl + 1) + spc;
skb_copy_from_linear_data_offset(skb, spc, inl + 1,
skb_headlen(skb) - spc);
if (skb_shinfo(skb)->nr_frags)
if (shinfo->nr_frags)
memcpy(((void *)(inl + 1)) + skb_headlen(skb) - spc,
fragptr, skb_frag_size(&skb_shinfo(skb)->frags[0]));
fragptr,
skb_frag_size(&shinfo->frags[0]));
}

wmb();
Expand Down Expand Up @@ -673,6 +677,7 @@ static void mlx4_bf_copy(void __iomem *dst, const void *src,

netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct skb_shared_info *shinfo = skb_shinfo(skb);
struct mlx4_en_priv *priv = netdev_priv(dev);
struct device *ddev = priv->ddev;
struct mlx4_en_tx_ring *ring;
Expand All @@ -686,7 +691,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
u32 index, bf_index;
__be32 op_own;
u16 vlan_tag = 0;
int i;
int i_frag;
int lso_header_size;
void *fragptr;
bool bounce = false;
Expand All @@ -702,7 +707,7 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
/* fetch ring->cons far ahead before needing it to avoid stall */
ring_cons = ACCESS_ONCE(ring->cons);

real_size = get_real_size(skb, dev, &lso_header_size);
real_size = get_real_size(skb, shinfo, dev, &lso_header_size);
if (unlikely(!real_size))
goto tx_drop;

Expand Down Expand Up @@ -776,21 +781,22 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
tx_info->data_offset = (void *)data - (void *)tx_desc;

tx_info->linear = (lso_header_size < skb_headlen(skb) &&
!is_inline(ring->inline_thold, skb, NULL)) ? 1 : 0;
!is_inline(ring->inline_thold, skb, shinfo, NULL)) ? 1 : 0;

tx_info->nr_maps = skb_shinfo(skb)->nr_frags + tx_info->linear;
tx_info->nr_maps = shinfo->nr_frags + tx_info->linear;
data += tx_info->nr_maps - 1;

if (is_inline(ring->inline_thold, skb, &fragptr)) {
if (is_inline(ring->inline_thold, skb, shinfo, &fragptr)) {
tx_info->inl = 1;
} else {
dma_addr_t dma = 0;
u32 byte_count = 0;

/* Map fragments if any */
for (i = skb_shinfo(skb)->nr_frags - 1; i >= 0; i--) {
for (i_frag = shinfo->nr_frags - 1; i_frag >= 0; i_frag--) {
const struct skb_frag_struct *frag;
frag = &skb_shinfo(skb)->frags[i];

frag = &shinfo->frags[i_frag];
byte_count = skb_frag_size(frag);
dma = skb_frag_dma_map(ddev, frag,
0, byte_count,
Expand Down Expand Up @@ -858,22 +864,25 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)

/* Handle LSO (TSO) packets */
if (lso_header_size) {
int i;

/* Mark opcode as LSO */
op_own = cpu_to_be32(MLX4_OPCODE_LSO | (1 << 6)) |
((ring->prod & ring->size) ?
cpu_to_be32(MLX4_EN_BIT_DESC_OWN) : 0);

/* Fill in the LSO prefix */
tx_desc->lso.mss_hdr_size = cpu_to_be32(
skb_shinfo(skb)->gso_size << 16 | lso_header_size);
shinfo->gso_size << 16 | lso_header_size);

/* Copy headers;
* note that we already verified that it is linear */
memcpy(tx_desc->lso.header, skb->data, lso_header_size);

ring->tso_packets++;
i = ((skb->len - lso_header_size) / skb_shinfo(skb)->gso_size) +
!!((skb->len - lso_header_size) % skb_shinfo(skb)->gso_size);

i = ((skb->len - lso_header_size) / shinfo->gso_size) +
!!((skb->len - lso_header_size) % shinfo->gso_size);
tx_info->nr_bytes = skb->len + (i - 1) * lso_header_size;
ring->packets += i;
} else {
Expand All @@ -889,7 +898,8 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
AVG_PERF_COUNTER(priv->pstats.tx_pktsz_avg, skb->len);

if (tx_info->inl) {
build_inline_wqe(tx_desc, skb, real_size, &vlan_tag, tx_ind, fragptr);
build_inline_wqe(tx_desc, skb, shinfo, real_size, &vlan_tag,
tx_ind, fragptr);
tx_info->inl = 1;
}

Expand Down Expand Up @@ -958,8 +968,8 @@ netdev_tx_t mlx4_en_xmit(struct sk_buff *skb, struct net_device *dev)
tx_drop_unmap:
en_err(priv, "DMA mapping error\n");

for (i++; i < skb_shinfo(skb)->nr_frags; i++) {
data++;
while (++i_frag < shinfo->nr_frags) {
++data;
dma_unmap_page(ddev, (dma_addr_t) be64_to_cpu(data->addr),
be32_to_cpu(data->byte_count),
PCI_DMA_TODEVICE);
Expand Down

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