qlcnic: Code optimization patch

Optimized code resulted in achieving lower CPU utilization on transmit path
and higher throughput for small packet sizes (64 bytes).

Signed-off-by: Anirban Chakraborty <anirban.chakraborty@qlogic.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 101 insertions, 109 deletions

diff --git a/drivers/net/qlcnic/qlcnic_main.c b/drivers/net/qlcnic/qlcnic_main.c
index dde7e4403830..3b740f55ca42 100644
--- a/drivers/net/qlcnic/qlcnic_main.c
+++ b/drivers/net/qlcnic/qlcnic_main.c
@@ -1861,6 +1861,7 @@ static void qlcnic_change_filter(struct qlcnic_adapter *adapter,
         vlan_req->vlan_id = vlan_id;
 
         tx_ring->producer = get_next_index(producer, tx_ring->num_desc);
+        smp_mb();
 }
 
 #define QLCNIC_MAC_HASH(MAC)\
@@ -1921,58 +1922,122 @@ qlcnic_send_filter(struct qlcnic_adapter *adapter,
         spin_unlock(&adapter->mac_learn_lock);
 }
 
-static void
-qlcnic_tso_check(struct net_device *netdev,
-                struct qlcnic_host_tx_ring *tx_ring,
+static int
+qlcnic_tx_pkt(struct qlcnic_adapter *adapter,
                 struct cmd_desc_type0 *first_desc,
                 struct sk_buff *skb)
 {
-        u8 opcode = TX_ETHER_PKT;
-        __be16 protocol = skb->protocol;
-        u16 flags = 0;
-        int copied, offset, copy_len, hdr_len = 0, tso = 0;
+        u8 opcode = 0, hdr_len = 0;
+        u16 flags = 0, vlan_tci = 0;
+        int copied, offset, copy_len;
         struct cmd_desc_type0 *hwdesc;
         struct vlan_ethhdr *vh;
-        struct qlcnic_adapter *adapter = netdev_priv(netdev);
+        struct qlcnic_host_tx_ring *tx_ring = adapter->tx_ring;
+        u16 protocol = ntohs(skb->protocol);
         u32 producer = tx_ring->producer;
-        __le16 vlan_oob = first_desc->flags_opcode &
-                                cpu_to_le16(FLAGS_VLAN_OOB);
+
+        if (protocol == ETH_P_8021Q) {
+                vh = (struct vlan_ethhdr *)skb->data;
+                flags = FLAGS_VLAN_TAGGED;
+                vlan_tci = vh->h_vlan_TCI;
+        } else if (vlan_tx_tag_present(skb)) {
+                flags = FLAGS_VLAN_OOB;
+                vlan_tci = vlan_tx_tag_get(skb);
+        }
+        if (unlikely(adapter->pvid)) {
+                if (vlan_tci && !(adapter->flags & QLCNIC_TAGGING_ENABLED))
+                        return -EIO;
+                if (vlan_tci && (adapter->flags & QLCNIC_TAGGING_ENABLED))
+                        goto set_flags;
+
+                flags = FLAGS_VLAN_OOB;
+                vlan_tci = adapter->pvid;
+        }
+set_flags:
+        qlcnic_set_tx_vlan_tci(first_desc, vlan_tci);
+        qlcnic_set_tx_flags_opcode(first_desc, flags, opcode);
 
         if (*(skb->data) & BIT_0) {
                 flags |= BIT_0;
                 memcpy(&first_desc->eth_addr, skb->data, ETH_ALEN);
         }
-
-        if ((netdev->features & (NETIF_F_TSO | NETIF_F_TSO6)) &&
+        opcode = TX_ETHER_PKT;
+        if ((adapter->netdev->features & (NETIF_F_TSO | NETIF_F_TSO6)) &&
                         skb_shinfo(skb)->gso_size > 0) {
 
                 hdr_len = skb_transport_offset(skb) + tcp_hdrlen(skb);
 
                 first_desc->mss = cpu_to_le16(skb_shinfo(skb)->gso_size);
                 first_desc->total_hdr_length = hdr_len;
-                if (vlan_oob) {
+
+                opcode = (protocol == ETH_P_IPV6) ? TX_TCP_LSO6 : TX_TCP_LSO;
+
+                /* For LSO, we need to copy the MAC/IP/TCP headers into
+                * the descriptor ring */
+                copied = 0;
+                offset = 2;
+
+                if (flags & FLAGS_VLAN_OOB) {
                         first_desc->total_hdr_length += VLAN_HLEN;
                         first_desc->tcp_hdr_offset = VLAN_HLEN;
                         first_desc->ip_hdr_offset = VLAN_HLEN;
                         /* Only in case of TSO on vlan device */
                         flags |= FLAGS_VLAN_TAGGED;
+
+                        /* Create a TSO vlan header template for firmware */
+
+                        hwdesc = &tx_ring->desc_head[producer];
+                        tx_ring->cmd_buf_arr[producer].skb = NULL;
+
+                        copy_len = min((int)sizeof(struct cmd_desc_type0) -
+                                offset, hdr_len + VLAN_HLEN);
+
+                        vh = (struct vlan_ethhdr *)((char *) hwdesc + 2);
+                        skb_copy_from_linear_data(skb, vh, 12);
+                        vh->h_vlan_proto = htons(ETH_P_8021Q);
+                        vh->h_vlan_TCI = htons(vlan_tci);
+
+                        skb_copy_from_linear_data_offset(skb, 12,
+                                (char *)vh + 16, copy_len - 16);
+
+                        copied = copy_len - VLAN_HLEN;
+                        offset = 0;
+
+                        producer = get_next_index(producer, tx_ring->num_desc);
                 }
 
-                opcode = (protocol == cpu_to_be16(ETH_P_IPV6)) ?
-                                TX_TCP_LSO6 : TX_TCP_LSO;
-                tso = 1;
+                while (copied < hdr_len) {
+
+                        copy_len = min((int)sizeof(struct cmd_desc_type0) -
+                                offset, (hdr_len - copied));
+
+                        hwdesc = &tx_ring->desc_head[producer];
+                        tx_ring->cmd_buf_arr[producer].skb = NULL;
+
+                        skb_copy_from_linear_data_offset(skb, copied,
+                                 (char *) hwdesc + offset, copy_len);
+
+                        copied += copy_len;
+                        offset = 0;
+
+                        producer = get_next_index(producer, tx_ring->num_desc);
+                }
+
+                tx_ring->producer = producer;
+                smp_mb();
+                adapter->stats.lso_frames++;
 
         } else if (skb->ip_summed == CHECKSUM_PARTIAL) {
                 u8 l4proto;
 
-                if (protocol == cpu_to_be16(ETH_P_IP)) {
+                if (protocol == ETH_P_IP) {
                         l4proto = ip_hdr(skb)->protocol;
 
                         if (l4proto == IPPROTO_TCP)
                                 opcode = TX_TCP_PKT;
                         else if (l4proto == IPPROTO_UDP)
                                 opcode = TX_UDP_PKT;
-                } else if (protocol == cpu_to_be16(ETH_P_IPV6)) {
+                } else if (protocol == ETH_P_IPV6) {
                         l4proto = ipv6_hdr(skb)->nexthdr;
 
                         if (l4proto == IPPROTO_TCP)
@@ -1981,63 +2046,11 @@ qlcnic_tso_check(struct net_device *netdev,
                                 opcode = TX_UDPV6_PKT;
                 }
         }
-
         first_desc->tcp_hdr_offset += skb_transport_offset(skb);
         first_desc->ip_hdr_offset += skb_network_offset(skb);
         qlcnic_set_tx_flags_opcode(first_desc, flags, opcode);
 
-        if (!tso)
-                return;
-
-        /* For LSO, we need to copy the MAC/IP/TCP headers into
-         * the descriptor ring
-         */
-        copied = 0;
-        offset = 2;
-
-        if (vlan_oob) {
-                /* Create a TSO vlan header template for firmware */
-
-                hwdesc = &tx_ring->desc_head[producer];
-                tx_ring->cmd_buf_arr[producer].skb = NULL;
-
-                copy_len = min((int)sizeof(struct cmd_desc_type0) - offset,
-                                hdr_len + VLAN_HLEN);
-
-                vh = (struct vlan_ethhdr *)((char *)hwdesc + 2);
-                skb_copy_from_linear_data(skb, vh, 12);
-                vh->h_vlan_proto = htons(ETH_P_8021Q);
-                vh->h_vlan_TCI = (__be16)swab16((u16)first_desc->vlan_TCI);
-
-                skb_copy_from_linear_data_offset(skb, 12,
-                                (char *)vh + 16, copy_len - 16);
-
-                copied = copy_len - VLAN_HLEN;
-                offset = 0;
-
-                producer = get_next_index(producer, tx_ring->num_desc);
-        }
-
-        while (copied < hdr_len) {
-
-                copy_len = min((int)sizeof(struct cmd_desc_type0) - offset,
-                                (hdr_len - copied));
-
-                hwdesc = &tx_ring->desc_head[producer];
-                tx_ring->cmd_buf_arr[producer].skb = NULL;
-
-                skb_copy_from_linear_data_offset(skb, copied,
-                                 (char *)hwdesc + offset, copy_len);
-
-                copied += copy_len;
-                offset = 0;
-
-                producer = get_next_index(producer, tx_ring->num_desc);
-        }
-
-        tx_ring->producer = producer;
-        barrier();
-        adapter->stats.lso_frames++;
+        return 0;
 }
 
 static int
@@ -2088,39 +2101,21 @@ out_err:
         return -ENOMEM;
 }
 
-static int
-qlcnic_check_tx_tagging(struct qlcnic_adapter *adapter,
-                        struct sk_buff *skb,
-                        struct cmd_desc_type0 *first_desc)
+static void
+qlcnic_unmap_buffers(struct pci_dev *pdev, struct sk_buff *skb,
+                        struct qlcnic_cmd_buffer *pbuf)
 {
-        u8 opcode = 0;
-        u16 flags = 0;
-        __be16 protocol = skb->protocol;
-        struct vlan_ethhdr *vh;
+        struct qlcnic_skb_frag *nf = &pbuf->frag_array[0];
+        int nr_frags = skb_shinfo(skb)->nr_frags;
+        int i;
 
-        if (protocol == cpu_to_be16(ETH_P_8021Q)) {
-                vh = (struct vlan_ethhdr *)skb->data;
-                protocol = vh->h_vlan_encapsulated_proto;
-                flags = FLAGS_VLAN_TAGGED;
-                qlcnic_set_tx_vlan_tci(first_desc, ntohs(vh->h_vlan_TCI));
-        } else if (vlan_tx_tag_present(skb)) {
-                flags = FLAGS_VLAN_OOB;
-                qlcnic_set_tx_vlan_tci(first_desc, vlan_tx_tag_get(skb));
+        for (i = 0; i < nr_frags; i++) {
+                nf = &pbuf->frag_array[i+1];
+                pci_unmap_page(pdev, nf->dma, nf->length, PCI_DMA_TODEVICE);
         }
-        if (unlikely(adapter->pvid)) {
-                if (first_desc->vlan_TCI &&
-                                !(adapter->flags & QLCNIC_TAGGING_ENABLED))
-                        return -EIO;
-                if (first_desc->vlan_TCI &&
-                                (adapter->flags & QLCNIC_TAGGING_ENABLED))
-                        goto set_flags;
 
-                flags = FLAGS_VLAN_OOB;
-                qlcnic_set_tx_vlan_tci(first_desc, adapter->pvid);
-        }
-set_flags:
-        qlcnic_set_tx_flags_opcode(first_desc, flags, opcode);
-        return 0;
+        nf = &pbuf->frag_array[0];
+        pci_unmap_single(pdev, nf->dma, skb_headlen(skb), PCI_DMA_TODEVICE);
 }
 
 static inline void
@@ -2144,7 +2139,7 @@ qlcnic_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
         int i, k;
 
         u32 producer;
-        int frag_count, no_of_desc;
+        int frag_count;
         u32 num_txd = tx_ring->num_desc;
 
         if (!test_bit(__QLCNIC_DEV_UP, &adapter->state)) {
@@ -2161,12 +2156,8 @@ qlcnic_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
 
         frag_count = skb_shinfo(skb)->nr_frags + 1;
 
-        /* 4 fragments per cmd des */
-        no_of_desc = (frag_count + 3) >> 2;
-
         if (unlikely(qlcnic_tx_avail(tx_ring) <= TX_STOP_THRESH)) {
                 netif_stop_queue(netdev);
-                smp_mb();
                 if (qlcnic_tx_avail(tx_ring) > TX_STOP_THRESH)
                         netif_start_queue(netdev);
                 else {
@@ -2183,9 +2174,6 @@ qlcnic_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
         first_desc = hwdesc = &tx_ring->desc_head[producer];
         qlcnic_clear_cmddesc((u64 *)hwdesc);
 
-        if (qlcnic_check_tx_tagging(adapter, skb, first_desc))
-                goto drop_packet;
-
         if (qlcnic_map_tx_skb(pdev, skb, pbuf)) {
                 adapter->stats.tx_dma_map_error++;
                 goto drop_packet;
@@ -2229,8 +2217,10 @@ qlcnic_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
         }
 
         tx_ring->producer = get_next_index(producer, num_txd);
+        smp_mb();
 
-        qlcnic_tso_check(netdev, tx_ring, first_desc, skb);
+        if (unlikely(qlcnic_tx_pkt(adapter, first_desc, skb)))
+                goto unwind_buff;
 
         if (qlcnic_mac_learn)
                 qlcnic_send_filter(adapter, tx_ring, first_desc, skb);
@@ -2242,6 +2232,8 @@ qlcnic_xmit_frame(struct sk_buff *skb, struct net_device *netdev)
 
         return NETDEV_TX_OK;
 
+unwind_buff:
+        qlcnic_unmap_buffers(pdev, skb, pbuf);
 drop_packet:
         adapter->stats.txdropped++;
         dev_kfree_skb_any(skb);