igb: Consolidate creation of Tx context descriptors into a single function

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>

1 files changed, 106 insertions, 127 deletions

diff --git a/drivers/net/ethernet/intel/igb/igb_main.c b/drivers/net/ethernet/intel/igb/igb_main.c
index 2bdc78368b64..a0bb81d9ef1b 100644
--- a/drivers/net/ethernet/intel/igb/igb_main.c
+++ b/drivers/net/ethernet/intel/igb/igb_main.c
@@ -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>
@@ -3960,16 +3963,39 @@ set_itr_now:
 #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);
@@ -3977,8 +4003,8 @@ static inline int igb_tso(struct igb_ring *tx_ring,
                         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);
@@ -3988,6 +4014,7 @@ 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,
@@ -3995,131 +4022,85 @@ static inline int igb_tso(struct igb_ring *tx_ring,
                                                        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
@@ -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);
@@ -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,
@@ -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;
 
@@ -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;
@@ -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))
@@ -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,