forcedeth: tx data path optimization

This patch optimizes the tx data paths and cleans up the code (removes
vlan from descr1/2 since only valid for desc3, changes to make code
easier to read, etc).

Signed-Off-By: Ayaz Abdulla <aabdulla@nvidia.com>

Signed-off-by: Jeff Garzik <jeff@garzik.org>

1 files changed, 58 insertions, 57 deletions

diff --git a/drivers/net/forcedeth.c b/drivers/net/forcedeth.c
index 75906ade76f5..27b6bf846000 100644
--- a/drivers/net/forcedeth.c
+++ b/drivers/net/forcedeth.c
@@ -1563,7 +1563,6 @@ static int nv_start_xmit(struct sk_buff *skb, struct net_device *dev)
         u32 size = skb->len-skb->data_len;
         u32 entries = (size >> NV_TX2_TSO_MAX_SHIFT) + ((size & (NV_TX2_TSO_MAX_SIZE-1)) ? 1 : 0);
         u32 empty_slots;
-        u32 tx_flags_vlan = 0;
         struct ring_desc* put_tx;
         struct ring_desc* start_tx;
         struct ring_desc* prev_tx;
@@ -1576,7 +1575,7 @@ static int nv_start_xmit(struct sk_buff *skb, struct net_device *dev)
         }
 
         empty_slots = nv_get_empty_tx_slots(np);
-        if (empty_slots <= entries) {
+        if (unlikely(empty_slots <= entries)) {
                 spin_lock_irq(&np->lock);
                 netif_stop_queue(dev);
                 np->tx_stop = 1;
@@ -1596,12 +1595,13 @@ static int nv_start_xmit(struct sk_buff *skb, struct net_device *dev)
                 np->put_tx_ctx->dma_len = bcnt;
                 put_tx->buf = cpu_to_le32(np->put_tx_ctx->dma);
                 put_tx->flaglen = cpu_to_le32((bcnt-1) | tx_flags);
+
                 tx_flags = np->tx_flags;
                 offset += bcnt;
                 size -= bcnt;
-                if (put_tx++ == np->last_tx.orig)
+                if (unlikely(put_tx++ == np->last_tx.orig))
                         put_tx = np->first_tx.orig;
-                if (np->put_tx_ctx++ == np->last_tx_ctx)
+                if (unlikely(np->put_tx_ctx++ == np->last_tx_ctx))
                         np->put_tx_ctx = np->first_tx_ctx;
         } while (size);
 
@@ -1618,14 +1618,14 @@ static int nv_start_xmit(struct sk_buff *skb, struct net_device *dev)
                         np->put_tx_ctx->dma = pci_map_page(np->pci_dev, frag->page, frag->page_offset+offset, bcnt,
                                                            PCI_DMA_TODEVICE);
                         np->put_tx_ctx->dma_len = bcnt;
-
                         put_tx->buf = cpu_to_le32(np->put_tx_ctx->dma);
                         put_tx->flaglen = cpu_to_le32((bcnt-1) | tx_flags);
+
                         offset += bcnt;
                         size -= bcnt;
-                        if (put_tx++ == np->last_tx.orig)
+                        if (unlikely(put_tx++ == np->last_tx.orig))
                                 put_tx = np->first_tx.orig;
-                        if (np->put_tx_ctx++ == np->last_tx_ctx)
+                        if (unlikely(np->put_tx_ctx++ == np->last_tx_ctx))
                                 np->put_tx_ctx = np->first_tx_ctx;
                 } while (size);
         }
@@ -1642,11 +1642,6 @@ static int nv_start_xmit(struct sk_buff *skb, struct net_device *dev)
                 tx_flags_extra = skb->ip_summed == CHECKSUM_PARTIAL ?
                          NV_TX2_CHECKSUM_L3 | NV_TX2_CHECKSUM_L4 : 0;
 
-        /* vlan tag */
-        if (np->vlangrp && vlan_tx_tag_present(skb)) {
-                tx_flags_vlan = NV_TX3_VLAN_TAG_PRESENT | vlan_tx_tag_get(skb);
-        }
-
         spin_lock_irq(&np->lock);
 
         /* set tx flags */
@@ -1669,7 +1664,6 @@ static int nv_start_xmit(struct sk_buff *skb, struct net_device *dev)
 
         dev->trans_start = jiffies;
         writel(NVREG_TXRXCTL_KICK|np->txrxctl_bits, get_hwbase(dev) + NvRegTxRxControl);
-        pci_push(get_hwbase(dev));
         return NETDEV_TX_OK;
 }
 
@@ -1677,7 +1671,7 @@ static int nv_start_xmit_optimized(struct sk_buff *skb, struct net_device *dev)
 {
         struct fe_priv *np = netdev_priv(dev);
         u32 tx_flags = 0;
-        u32 tx_flags_extra = NV_TX2_LASTPACKET;
+        u32 tx_flags_extra;
         unsigned int fragments = skb_shinfo(skb)->nr_frags;
         unsigned int i;
         u32 offset = 0;
@@ -1685,7 +1679,6 @@ static int nv_start_xmit_optimized(struct sk_buff *skb, struct net_device *dev)
         u32 size = skb->len-skb->data_len;
         u32 entries = (size >> NV_TX2_TSO_MAX_SHIFT) + ((size & (NV_TX2_TSO_MAX_SIZE-1)) ? 1 : 0);
         u32 empty_slots;
-        u32 tx_flags_vlan = 0;
         struct ring_desc_ex* put_tx;
         struct ring_desc_ex* start_tx;
         struct ring_desc_ex* prev_tx;
@@ -1698,7 +1691,7 @@ static int nv_start_xmit_optimized(struct sk_buff *skb, struct net_device *dev)
         }
 
         empty_slots = nv_get_empty_tx_slots(np);
-        if (empty_slots <= entries) {
+        if (unlikely(empty_slots <= entries)) {
                 spin_lock_irq(&np->lock);
                 netif_stop_queue(dev);
                 np->tx_stop = 1;
@@ -1719,12 +1712,13 @@ static int nv_start_xmit_optimized(struct sk_buff *skb, struct net_device *dev)
                 put_tx->bufhigh = cpu_to_le64(np->put_tx_ctx->dma) >> 32;
                 put_tx->buflow = cpu_to_le64(np->put_tx_ctx->dma) & 0x0FFFFFFFF;
                 put_tx->flaglen = cpu_to_le32((bcnt-1) | tx_flags);
-                tx_flags = np->tx_flags;
+
+                tx_flags = NV_TX2_VALID;
                 offset += bcnt;
                 size -= bcnt;
-                if (put_tx++ == np->last_tx.ex)
+                if (unlikely(put_tx++ == np->last_tx.ex))
                         put_tx = np->first_tx.ex;
-                if (np->put_tx_ctx++ == np->last_tx_ctx)
+                if (unlikely(np->put_tx_ctx++ == np->last_tx_ctx))
                         np->put_tx_ctx = np->first_tx_ctx;
         } while (size);
 
@@ -1741,21 +1735,21 @@ static int nv_start_xmit_optimized(struct sk_buff *skb, struct net_device *dev)
                         np->put_tx_ctx->dma = pci_map_page(np->pci_dev, frag->page, frag->page_offset+offset, bcnt,
                                                            PCI_DMA_TODEVICE);
                         np->put_tx_ctx->dma_len = bcnt;
-
                         put_tx->bufhigh = cpu_to_le64(np->put_tx_ctx->dma) >> 32;
                         put_tx->buflow = cpu_to_le64(np->put_tx_ctx->dma) & 0x0FFFFFFFF;
                         put_tx->flaglen = cpu_to_le32((bcnt-1) | tx_flags);
+
                         offset += bcnt;
                         size -= bcnt;
-                        if (put_tx++ == np->last_tx.ex)
+                        if (unlikely(put_tx++ == np->last_tx.ex))
                                 put_tx = np->first_tx.ex;
-                        if (np->put_tx_ctx++ == np->last_tx_ctx)
+                        if (unlikely(np->put_tx_ctx++ == np->last_tx_ctx))
                                 np->put_tx_ctx = np->first_tx_ctx;
                 } while (size);
         }
 
         /* set last fragment flag  */
-        prev_tx->flaglen |= cpu_to_le32(tx_flags_extra);
+        prev_tx->flaglen |= cpu_to_le32(NV_TX2_LASTPACKET);
 
         /* save skb in this slot's context area */
         prev_tx_ctx->skb = skb;
@@ -1767,14 +1761,18 @@ static int nv_start_xmit_optimized(struct sk_buff *skb, struct net_device *dev)
                          NV_TX2_CHECKSUM_L3 | NV_TX2_CHECKSUM_L4 : 0;
 
         /* vlan tag */
-        if (np->vlangrp && vlan_tx_tag_present(skb)) {
-                tx_flags_vlan = NV_TX3_VLAN_TAG_PRESENT | vlan_tx_tag_get(skb);
+        if (likely(!np->vlangrp)) {
+                start_tx->txvlan = 0;
+        } else {
+                if (vlan_tx_tag_present(skb))
+                        start_tx->txvlan = cpu_to_le32(NV_TX3_VLAN_TAG_PRESENT | vlan_tx_tag_get(skb));
+                else
+                        start_tx->txvlan = 0;
         }
 
         spin_lock_irq(&np->lock);
 
         /* set tx flags */
-        start_tx->txvlan = cpu_to_le32(tx_flags_vlan);
         start_tx->flaglen |= cpu_to_le32(tx_flags | tx_flags_extra);
         np->put_tx.ex = put_tx;
 
@@ -1794,7 +1792,6 @@ static int nv_start_xmit_optimized(struct sk_buff *skb, struct net_device *dev)
 
         dev->trans_start = jiffies;
         writel(NVREG_TXRXCTL_KICK|np->txrxctl_bits, get_hwbase(dev) + NvRegTxRxControl);
-        pci_push(get_hwbase(dev));
         return NETDEV_TX_OK;
 }
 
@@ -1807,21 +1804,22 @@ static void nv_tx_done(struct net_device *dev)
 {
         struct fe_priv *np = netdev_priv(dev);
         u32 flags;
-        struct sk_buff *skb;
         struct ring_desc* orig_get_tx = np->get_tx.orig;
 
-        while (np->get_tx.orig != np->put_tx.orig) {
-                flags = le32_to_cpu(np->get_tx.orig->flaglen);
+        while ((np->get_tx.orig != np->put_tx.orig) &&
+               !((flags = le32_to_cpu(np->get_tx.orig->flaglen)) & NV_TX_VALID)) {
 
                 dprintk(KERN_DEBUG "%s: nv_tx_done: flags 0x%x.\n",
                                         dev->name, flags);
-                if (flags & NV_TX_VALID)
-                        break;
+
+                pci_unmap_page(np->pci_dev, np->get_tx_ctx->dma,
+                               np->get_tx_ctx->dma_len,
+                               PCI_DMA_TODEVICE);
+                np->get_tx_ctx->dma = 0;
+
                 if (np->desc_ver == DESC_VER_1) {
                         if (flags & NV_TX_LASTPACKET) {
-                                skb = np->get_tx_ctx->skb;
-                                if (flags & (NV_TX_RETRYERROR|NV_TX_CARRIERLOST|NV_TX_LATECOLLISION|
-                                             NV_TX_UNDERFLOW|NV_TX_ERROR)) {
+                                if (flags & NV_TX_ERROR) {
                                         if (flags & NV_TX_UNDERFLOW)
                                                 np->stats.tx_fifo_errors++;
                                         if (flags & NV_TX_CARRIERLOST)
@@ -1829,14 +1827,14 @@ static void nv_tx_done(struct net_device *dev)
                                         np->stats.tx_errors++;
                                 } else {
                                         np->stats.tx_packets++;
-                                        np->stats.tx_bytes += skb->len;
+                                        np->stats.tx_bytes += np->get_tx_ctx->skb->len;
                                 }
+                                dev_kfree_skb_any(np->get_tx_ctx->skb);
+                                np->get_tx_ctx->skb = NULL;
                         }
                 } else {
                         if (flags & NV_TX2_LASTPACKET) {
-                                skb = np->get_tx_ctx->skb;
-                                if (flags & (NV_TX2_RETRYERROR|NV_TX2_CARRIERLOST|NV_TX2_LATECOLLISION|
-                                             NV_TX2_UNDERFLOW|NV_TX2_ERROR)) {
+                                if (flags & NV_TX2_ERROR) {
                                         if (flags & NV_TX2_UNDERFLOW)
                                                 np->stats.tx_fifo_errors++;
                                         if (flags & NV_TX2_CARRIERLOST)
@@ -1844,17 +1842,18 @@ static void nv_tx_done(struct net_device *dev)
                                         np->stats.tx_errors++;
                                 } else {
                                         np->stats.tx_packets++;
-                                        np->stats.tx_bytes += skb->len;
+                                        np->stats.tx_bytes += np->get_tx_ctx->skb->len;
                                 }
+                                dev_kfree_skb_any(np->get_tx_ctx->skb);
+                                np->get_tx_ctx->skb = NULL;
                         }
                 }
-                nv_release_txskb(dev, np->get_tx_ctx);
-                if (np->get_tx.orig++ == np->last_tx.orig)
+                if (unlikely(np->get_tx.orig++ == np->last_tx.orig))
                         np->get_tx.orig = np->first_tx.orig;
-                if (np->get_tx_ctx++ == np->last_tx_ctx)
+                if (unlikely(np->get_tx_ctx++ == np->last_tx_ctx))
                         np->get_tx_ctx = np->first_tx_ctx;
         }
-        if ((np->tx_stop == 1) && (np->get_tx.orig != orig_get_tx)) {
+        if (unlikely((np->tx_stop == 1) && (np->get_tx.orig != orig_get_tx))) {
                 np->tx_stop = 0;
                 netif_wake_queue(dev);
         }
@@ -1864,20 +1863,21 @@ static void nv_tx_done_optimized(struct net_device *dev)
 {
         struct fe_priv *np = netdev_priv(dev);
         u32 flags;
-        struct sk_buff *skb;
         struct ring_desc_ex* orig_get_tx = np->get_tx.ex;
 
-        while (np->get_tx.ex == np->put_tx.ex) {
-                flags = le32_to_cpu(np->get_tx.ex->flaglen);
+        while ((np->get_tx.ex != np->put_tx.ex) &&
+               !((flags = le32_to_cpu(np->get_tx.ex->flaglen)) & NV_TX_VALID)) {
 
                 dprintk(KERN_DEBUG "%s: nv_tx_done_optimized: flags 0x%x.\n",
                                         dev->name, flags);
-                if (flags & NV_TX_VALID)
-                        break;
+
+                pci_unmap_page(np->pci_dev, np->get_tx_ctx->dma,
+                               np->get_tx_ctx->dma_len,
+                               PCI_DMA_TODEVICE);
+                np->get_tx_ctx->dma = 0;
+
                 if (flags & NV_TX2_LASTPACKET) {
-                        skb = np->get_tx_ctx->skb;
-                        if (flags & (NV_TX2_RETRYERROR|NV_TX2_CARRIERLOST|NV_TX2_LATECOLLISION|
-                                     NV_TX2_UNDERFLOW|NV_TX2_ERROR)) {
+                        if (flags & NV_TX2_ERROR) {
                                 if (flags & NV_TX2_UNDERFLOW)
                                         np->stats.tx_fifo_errors++;
                                 if (flags & NV_TX2_CARRIERLOST)
@@ -1885,16 +1885,17 @@ static void nv_tx_done_optimized(struct net_device *dev)
                                 np->stats.tx_errors++;
                         } else {
                                 np->stats.tx_packets++;
-                                np->stats.tx_bytes += skb->len;
+                                np->stats.tx_bytes += np->get_tx_ctx->skb->len;
                         }
+                        dev_kfree_skb_any(np->get_tx_ctx->skb);
+                        np->get_tx_ctx->skb = NULL;
                 }
-                nv_release_txskb(dev, np->get_tx_ctx);
-                if (np->get_tx.ex++ == np->last_tx.ex)
+                if (unlikely(np->get_tx.ex++ == np->last_tx.ex))
                         np->get_tx.ex = np->first_tx.ex;
-                if (np->get_tx_ctx++ == np->last_tx_ctx)
+                if (unlikely(np->get_tx_ctx++ == np->last_tx_ctx))
                         np->get_tx_ctx = np->first_tx_ctx;
         }
-        if ((np->tx_stop == 1) && (np->get_tx.ex != orig_get_tx)) {
+        if (unlikely((np->tx_stop == 1) && (np->get_tx.ex != orig_get_tx))) {
                 np->tx_stop = 0;
                 netif_wake_queue(dev);
         }