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igb: Consolidate creation of Tx context descriptors into a single fun…
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…ction

This patch is meant to simplify the transmit path by reducing the overhead
for creating a transmit context descriptor.  The current implementation is
split with igb_tso and igb_tx_csum doing two separate implementations on
how to setup the tx_buffer_info structure and the tx_desc.  By combining
them it is possible to reduce code and simplify things since now only one
function will create context descriptors.

Signed-off-by: Alexander Duyck <alexander.h.duyck@intel.com>
Tested-by:  Aaron Brown  <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
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Alexander Duyck authored and Jeff Kirsher committed Oct 7, 2011
1 parent 0603464 commit 7d13a7d
Showing 1 changed file with 106 additions and 127 deletions.
233 changes: 106 additions & 127 deletions drivers/net/ethernet/intel/igb/igb_main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -45,6 +45,9 @@
#include <linux/pci-aspm.h>
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/ip.h>
#include <linux/tcp.h>
#include <linux/sctp.h>
#include <linux/if_ether.h>
#include <linux/aer.h>
#include <linux/prefetch.h>
Expand Down Expand Up @@ -3960,25 +3963,48 @@ static void igb_set_itr(struct igb_adapter *adapter)
#define IGB_TX_FLAGS_VLAN_MASK 0xffff0000
#define IGB_TX_FLAGS_VLAN_SHIFT 16

void igb_tx_ctxtdesc(struct igb_ring *tx_ring, u32 vlan_macip_lens,
u32 type_tucmd, u32 mss_l4len_idx)
{
struct e1000_adv_tx_context_desc *context_desc;
u16 i = tx_ring->next_to_use;

context_desc = IGB_TX_CTXTDESC(tx_ring, i);

i++;
tx_ring->next_to_use = (i < tx_ring->count) ? i : 0;

/* set bits to identify this as an advanced context descriptor */
type_tucmd |= E1000_TXD_CMD_DEXT | E1000_ADVTXD_DTYP_CTXT;

/* For 82575, context index must be unique per ring. */
if (tx_ring->flags & IGB_RING_FLAG_TX_CTX_IDX)
mss_l4len_idx |= tx_ring->reg_idx << 4;

context_desc->vlan_macip_lens = cpu_to_le32(vlan_macip_lens);
context_desc->seqnum_seed = 0;
context_desc->type_tucmd_mlhl = cpu_to_le32(type_tucmd);
context_desc->mss_l4len_idx = cpu_to_le32(mss_l4len_idx);
}

static inline int igb_tso(struct igb_ring *tx_ring,
struct sk_buff *skb, u32 tx_flags, u8 *hdr_len)
{
struct e1000_adv_tx_context_desc *context_desc;
unsigned int i;
int err;
struct igb_tx_buffer *buffer_info;
u32 info = 0, tu_cmd = 0;
u32 mss_l4len_idx;
u8 l4len;
u32 vlan_macip_lens, type_tucmd;
u32 mss_l4len_idx, l4len;

if (!skb_is_gso(skb))
return 0;

if (skb_header_cloned(skb)) {
err = pskb_expand_head(skb, 0, 0, GFP_ATOMIC);
if (err)
return err;
}

l4len = tcp_hdrlen(skb);
*hdr_len += l4len;
/* ADV DTYP TUCMD MKRLOC/ISCSIHEDLEN */
type_tucmd = E1000_ADVTXD_TUCMD_L4T_TCP;

if (skb->protocol == htons(ETH_P_IP)) {
struct iphdr *iph = ip_hdr(skb);
Expand All @@ -3988,138 +4014,93 @@ static inline int igb_tso(struct igb_ring *tx_ring,
iph->daddr, 0,
IPPROTO_TCP,
0);
type_tucmd |= E1000_ADVTXD_TUCMD_IPV4;
} else if (skb_is_gso_v6(skb)) {
ipv6_hdr(skb)->payload_len = 0;
tcp_hdr(skb)->check = ~csum_ipv6_magic(&ipv6_hdr(skb)->saddr,
&ipv6_hdr(skb)->daddr,
0, IPPROTO_TCP, 0);
}

i = tx_ring->next_to_use;

buffer_info = &tx_ring->tx_buffer_info[i];
context_desc = IGB_TX_CTXTDESC(tx_ring, i);
/* VLAN MACLEN IPLEN */
if (tx_flags & IGB_TX_FLAGS_VLAN)
info |= (tx_flags & IGB_TX_FLAGS_VLAN_MASK);
info |= (skb_network_offset(skb) << E1000_ADVTXD_MACLEN_SHIFT);
*hdr_len += skb_network_offset(skb);
info |= skb_network_header_len(skb);
*hdr_len += skb_network_header_len(skb);
context_desc->vlan_macip_lens = cpu_to_le32(info);

/* ADV DTYP TUCMD MKRLOC/ISCSIHEDLEN */
tu_cmd |= (E1000_TXD_CMD_DEXT | E1000_ADVTXD_DTYP_CTXT);

if (skb->protocol == htons(ETH_P_IP))
tu_cmd |= E1000_ADVTXD_TUCMD_IPV4;
tu_cmd |= E1000_ADVTXD_TUCMD_L4T_TCP;

context_desc->type_tucmd_mlhl = cpu_to_le32(tu_cmd);
l4len = tcp_hdrlen(skb);
*hdr_len = skb_transport_offset(skb) + l4len;

/* MSS L4LEN IDX */
mss_l4len_idx = (skb_shinfo(skb)->gso_size << E1000_ADVTXD_MSS_SHIFT);
mss_l4len_idx |= (l4len << E1000_ADVTXD_L4LEN_SHIFT);
mss_l4len_idx = l4len << E1000_ADVTXD_L4LEN_SHIFT;
mss_l4len_idx |= skb_shinfo(skb)->gso_size << E1000_ADVTXD_MSS_SHIFT;

/* For 82575, context index must be unique per ring. */
if (tx_ring->flags & IGB_RING_FLAG_TX_CTX_IDX)
mss_l4len_idx |= tx_ring->reg_idx << 4;

context_desc->mss_l4len_idx = cpu_to_le32(mss_l4len_idx);
context_desc->seqnum_seed = 0;

buffer_info->time_stamp = jiffies;
buffer_info->next_to_watch = i;
buffer_info->dma = 0;
i++;
if (i == tx_ring->count)
i = 0;
/* VLAN MACLEN IPLEN */
vlan_macip_lens = skb_network_header_len(skb);
vlan_macip_lens |= skb_network_offset(skb) << E1000_ADVTXD_MACLEN_SHIFT;
vlan_macip_lens |= tx_flags & IGB_TX_FLAGS_VLAN_MASK;

tx_ring->next_to_use = i;
igb_tx_ctxtdesc(tx_ring, vlan_macip_lens, type_tucmd, mss_l4len_idx);

return true;
return 1;
}

static inline bool igb_tx_csum(struct igb_ring *tx_ring,
struct sk_buff *skb, u32 tx_flags)
{
struct e1000_adv_tx_context_desc *context_desc;
struct device *dev = tx_ring->dev;
struct igb_tx_buffer *buffer_info;
u32 info = 0, tu_cmd = 0;
unsigned int i;

if ((skb->ip_summed == CHECKSUM_PARTIAL) ||
(tx_flags & IGB_TX_FLAGS_VLAN)) {
i = tx_ring->next_to_use;
buffer_info = &tx_ring->tx_buffer_info[i];
context_desc = IGB_TX_CTXTDESC(tx_ring, i);

if (tx_flags & IGB_TX_FLAGS_VLAN)
info |= (tx_flags & IGB_TX_FLAGS_VLAN_MASK);

info |= (skb_network_offset(skb) << E1000_ADVTXD_MACLEN_SHIFT);
if (skb->ip_summed == CHECKSUM_PARTIAL)
info |= skb_network_header_len(skb);

context_desc->vlan_macip_lens = cpu_to_le32(info);

tu_cmd |= (E1000_TXD_CMD_DEXT | E1000_ADVTXD_DTYP_CTXT);

if (skb->ip_summed == CHECKSUM_PARTIAL) {
__be16 protocol;
u32 vlan_macip_lens = 0;
u32 mss_l4len_idx = 0;
u32 type_tucmd = 0;

if (skb->protocol == cpu_to_be16(ETH_P_8021Q)) {
const struct vlan_ethhdr *vhdr =
(const struct vlan_ethhdr*)skb->data;

protocol = vhdr->h_vlan_encapsulated_proto;
} else {
protocol = skb->protocol;
if (skb->ip_summed != CHECKSUM_PARTIAL) {
if (!(tx_flags & IGB_TX_FLAGS_VLAN))
return false;
} else {
u8 l4_hdr = 0;
switch (skb->protocol) {
case __constant_htons(ETH_P_IP):
vlan_macip_lens |= skb_network_header_len(skb);
type_tucmd |= E1000_ADVTXD_TUCMD_IPV4;
l4_hdr = ip_hdr(skb)->protocol;
break;
case __constant_htons(ETH_P_IPV6):
vlan_macip_lens |= skb_network_header_len(skb);
l4_hdr = ipv6_hdr(skb)->nexthdr;
break;
default:
if (unlikely(net_ratelimit())) {
dev_warn(tx_ring->dev,
"partial checksum but proto=%x!\n",
skb->protocol);
}
break;
}

switch (protocol) {
case cpu_to_be16(ETH_P_IP):
tu_cmd |= E1000_ADVTXD_TUCMD_IPV4;
if (ip_hdr(skb)->protocol == IPPROTO_TCP)
tu_cmd |= E1000_ADVTXD_TUCMD_L4T_TCP;
else if (ip_hdr(skb)->protocol == IPPROTO_SCTP)
tu_cmd |= E1000_ADVTXD_TUCMD_L4T_SCTP;
break;
case cpu_to_be16(ETH_P_IPV6):
/* XXX what about other V6 headers?? */
if (ipv6_hdr(skb)->nexthdr == IPPROTO_TCP)
tu_cmd |= E1000_ADVTXD_TUCMD_L4T_TCP;
else if (ipv6_hdr(skb)->nexthdr == IPPROTO_SCTP)
tu_cmd |= E1000_ADVTXD_TUCMD_L4T_SCTP;
break;
default:
if (unlikely(net_ratelimit()))
dev_warn(dev,
"partial checksum but proto=%x!\n",
skb->protocol);
break;
switch (l4_hdr) {
case IPPROTO_TCP:
type_tucmd |= E1000_ADVTXD_TUCMD_L4T_TCP;
mss_l4len_idx = tcp_hdrlen(skb) <<
E1000_ADVTXD_L4LEN_SHIFT;
break;
case IPPROTO_SCTP:
type_tucmd |= E1000_ADVTXD_TUCMD_L4T_SCTP;
mss_l4len_idx = sizeof(struct sctphdr) <<
E1000_ADVTXD_L4LEN_SHIFT;
break;
case IPPROTO_UDP:
mss_l4len_idx = sizeof(struct udphdr) <<
E1000_ADVTXD_L4LEN_SHIFT;
break;
default:
if (unlikely(net_ratelimit())) {
dev_warn(tx_ring->dev,
"partial checksum but l4 proto=%x!\n",
l4_hdr);
}
break;
}
}

context_desc->type_tucmd_mlhl = cpu_to_le32(tu_cmd);
context_desc->seqnum_seed = 0;
if (tx_ring->flags & IGB_RING_FLAG_TX_CTX_IDX)
context_desc->mss_l4len_idx =
cpu_to_le32(tx_ring->reg_idx << 4);
vlan_macip_lens |= skb_network_offset(skb) << E1000_ADVTXD_MACLEN_SHIFT;
vlan_macip_lens |= tx_flags & IGB_TX_FLAGS_VLAN_MASK;

buffer_info->time_stamp = jiffies;
buffer_info->next_to_watch = i;
buffer_info->dma = 0;
igb_tx_ctxtdesc(tx_ring, vlan_macip_lens, type_tucmd, mss_l4len_idx);

i++;
if (i == tx_ring->count)
i = 0;
tx_ring->next_to_use = i;

return true;
}
return false;
return (skb->ip_summed == CHECKSUM_PARTIAL);
}

#define IGB_MAX_TXD_PWR 16
Expand All @@ -4140,8 +4121,6 @@ static inline int igb_tx_map(struct igb_ring *tx_ring, struct sk_buff *skb,
buffer_info = &tx_ring->tx_buffer_info[i];
BUG_ON(hlen >= IGB_MAX_DATA_PER_TXD);
buffer_info->length = hlen;
/* set time_stamp *before* dma to help avoid a possible race */
buffer_info->time_stamp = jiffies;
buffer_info->next_to_watch = i;
buffer_info->dma = dma_map_single(dev, skb->data, hlen,
DMA_TO_DEVICE);
Expand All @@ -4160,7 +4139,6 @@ static inline int igb_tx_map(struct igb_ring *tx_ring, struct sk_buff *skb,
buffer_info = &tx_ring->tx_buffer_info[i];
BUG_ON(len >= IGB_MAX_DATA_PER_TXD);
buffer_info->length = len;
buffer_info->time_stamp = jiffies;
buffer_info->next_to_watch = i;
buffer_info->mapped_as_page = true;
buffer_info->dma = skb_frag_dma_map(dev, frag, 0, len,
Expand All @@ -4176,6 +4154,7 @@ static inline int igb_tx_map(struct igb_ring *tx_ring, struct sk_buff *skb,
buffer_info->bytecount = ((gso_segs - 1) * hlen) + skb->len;
buffer_info->gso_segs = gso_segs;
tx_ring->tx_buffer_info[first].next_to_watch = i;
tx_ring->tx_buffer_info[first].time_stamp = jiffies;

return ++count;

Expand Down Expand Up @@ -4304,7 +4283,7 @@ static inline int igb_maybe_stop_tx(struct igb_ring *tx_ring, int size)
netdev_tx_t igb_xmit_frame_ring(struct sk_buff *skb,
struct igb_ring *tx_ring)
{
int tso = 0, count;
int tso, count;
u32 tx_flags = 0;
u16 first;
u8 hdr_len = 0;
Expand Down Expand Up @@ -4333,16 +4312,12 @@ netdev_tx_t igb_xmit_frame_ring(struct sk_buff *skb,
tx_flags |= IGB_TX_FLAGS_IPV4;

first = tx_ring->next_to_use;
if (skb_is_gso(skb)) {
tso = igb_tso(tx_ring, skb, tx_flags, &hdr_len);

if (tso < 0) {
dev_kfree_skb_any(skb);
return NETDEV_TX_OK;
}
}
tso = igb_tso(tx_ring, skb, tx_flags, &hdr_len);

if (tso)
if (tso < 0)
goto out_drop;
else if (tso)
tx_flags |= IGB_TX_FLAGS_TSO;
else if (igb_tx_csum(tx_ring, skb, tx_flags) &&
(skb->ip_summed == CHECKSUM_PARTIAL))
Expand All @@ -4366,6 +4341,10 @@ netdev_tx_t igb_xmit_frame_ring(struct sk_buff *skb,
igb_maybe_stop_tx(tx_ring, MAX_SKB_FRAGS + 4);

return NETDEV_TX_OK;

out_drop:
dev_kfree_skb_any(skb);
return NETDEV_TX_OK;
}

static inline struct igb_ring *igb_tx_queue_mapping(struct igb_adapter *adapter,
Expand Down

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