e1000: Fixes for packet split related issues

Fixes for packet split related issues
  * On platforms where PAGE_SIZE > 4K, driver will use only required number of
    pages compared to always using 3 pages.
  * Packet split won't be used if the PAGE_SIZE is > 16K
  * Adds a statistics counter to splits.
  * Setting the non Null ptr to zero sized buffers to solve packet split
    receive descriptor error
  * When the no of pages needed is calculated, the header buffer is not
    included for a given MTU.

Signed-off-by: Mallikarjuna R Chilakala <mallikarjuna.chilakala@intel.com>
Signed-off-by: Ganesh Venkatesan <ganesh.venkatesan@intel.com>
Signed-off-by: John Ronciak <john.ronciak@intel.com>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

3 files changed, 60 insertions, 38 deletions

diff --git a/drivers/net/e1000/e1000.h b/drivers/net/e1000/e1000.h
index 9b7274b111f3..3f653a93e1bc 100644
--- a/drivers/net/e1000/e1000.h
+++ b/drivers/net/e1000/e1000.h
@@ -169,8 +169,8 @@ struct e1000_buffer {
         uint16_t next_to_watch;
 };
 
-struct e1000_ps_page { struct page *ps_page[MAX_PS_BUFFERS]; };
-struct e1000_ps_page_dma { uint64_t ps_page_dma[MAX_PS_BUFFERS]; };
+struct e1000_ps_page { struct page *ps_page[PS_PAGE_BUFFERS]; };
+struct e1000_ps_page_dma { uint64_t ps_page_dma[PS_PAGE_BUFFERS]; };
 
 struct e1000_tx_ring {
         /* pointer to the descriptor ring memory */
@@ -300,10 +300,11 @@ struct e1000_adapter {
 
         uint64_t hw_csum_err;
         uint64_t hw_csum_good;
+        uint64_t rx_hdr_split;
         uint32_t rx_int_delay;
         uint32_t rx_abs_int_delay;
         boolean_t rx_csum;
-        boolean_t rx_ps;
+        unsigned int rx_ps_pages;
         uint32_t gorcl;
         uint64_t gorcl_old;
         uint16_t rx_ps_bsize0;
diff --git a/drivers/net/e1000/e1000_ethtool.c b/drivers/net/e1000/e1000_ethtool.c
index 6e7e34f59a34..183b583df1d7 100644
--- a/drivers/net/e1000/e1000_ethtool.c
+++ b/drivers/net/e1000/e1000_ethtool.c
@@ -91,7 +91,8 @@ static const struct e1000_stats e1000_gstrings_stats[] = {
         { "tx_flow_control_xoff", E1000_STAT(stats.xofftxc) },
         { "rx_long_byte_count", E1000_STAT(stats.gorcl) },
         { "rx_csum_offload_good", E1000_STAT(hw_csum_good) },
-        { "rx_csum_offload_errors", E1000_STAT(hw_csum_err) }
+        { "rx_csum_offload_errors", E1000_STAT(hw_csum_err) },
+        { "rx_header_split", E1000_STAT(rx_hdr_split) },
 };
 #define E1000_STATS_LEN \
         sizeof(e1000_gstrings_stats) / sizeof(struct e1000_stats)
diff --git a/drivers/net/e1000/e1000_main.c b/drivers/net/e1000/e1000_main.c
index ad92115f20a0..090229f7a95c 100644
--- a/drivers/net/e1000/e1000_main.c
+++ b/drivers/net/e1000/e1000_main.c
@@ -1484,12 +1484,16 @@ e1000_setup_all_rx_resources(struct e1000_adapter *adapter)
  * e1000_setup_rctl - configure the receive control registers
  * @adapter: Board private structure
  **/
-
+#define PAGE_USE_COUNT(S) (((S) >> PAGE_SHIFT) + \
+                        (((S) & (PAGE_SIZE - 1)) ? 1 : 0))
 static void
 e1000_setup_rctl(struct e1000_adapter *adapter)
 {
         uint32_t rctl, rfctl;
         uint32_t psrctl = 0;
+#ifdef CONFIG_E1000_PACKET_SPLIT
+        uint32_t pages = 0;
+#endif
 
         rctl = E1000_READ_REG(&adapter->hw, RCTL);
 
@@ -1543,11 +1547,14 @@ e1000_setup_rctl(struct e1000_adapter *adapter)
          * followed by the page buffers.  Therefore, skb->data is
          * sized to hold the largest protocol header.
          */
-        adapter->rx_ps = (adapter->hw.mac_type > e1000_82547_rev_2) 
-                          && (adapter->netdev->mtu 
-                              < ((3 * PAGE_SIZE) + adapter->rx_ps_bsize0));
+        pages = PAGE_USE_COUNT(adapter->netdev->mtu);
+        if ((adapter->hw.mac_type > e1000_82547_rev_2) && (pages <= 3) &&
+            PAGE_SIZE <= 16384)
+                adapter->rx_ps_pages = pages;
+        else
+                adapter->rx_ps_pages = 0;
 #endif
-        if(adapter->rx_ps) {
+        if (adapter->rx_ps_pages) {
                 /* Configure extra packet-split registers */
                 rfctl = E1000_READ_REG(&adapter->hw, RFCTL);
                 rfctl |= E1000_RFCTL_EXTEN;
@@ -1559,12 +1566,19 @@ e1000_setup_rctl(struct e1000_adapter *adapter)
                 
                 psrctl |= adapter->rx_ps_bsize0 >>
                         E1000_PSRCTL_BSIZE0_SHIFT;
-                psrctl |= PAGE_SIZE >>
-                        E1000_PSRCTL_BSIZE1_SHIFT;
-                psrctl |= PAGE_SIZE <<
-                        E1000_PSRCTL_BSIZE2_SHIFT;
-                psrctl |= PAGE_SIZE <<
-                        E1000_PSRCTL_BSIZE3_SHIFT;
+
+                switch (adapter->rx_ps_pages) {
+                case 3:
+                        psrctl |= PAGE_SIZE <<
+                                E1000_PSRCTL_BSIZE3_SHIFT;
+                case 2:
+                        psrctl |= PAGE_SIZE <<
+                                E1000_PSRCTL_BSIZE2_SHIFT;
+                case 1:
+                        psrctl |= PAGE_SIZE >>
+                                E1000_PSRCTL_BSIZE1_SHIFT;
+                        break;
+                }
 
                 E1000_WRITE_REG(&adapter->hw, PSRCTL, psrctl);
         }
@@ -1590,7 +1604,7 @@ e1000_configure_rx(struct e1000_adapter *adapter)
         int i;
 #endif
 
-        if(adapter->rx_ps) {
+        if (adapter->rx_ps_pages) {
                 rdlen = adapter->rx_ring[0].count *
                         sizeof(union e1000_rx_desc_packet_split);
                 adapter->clean_rx = e1000_clean_rx_irq_ps;
@@ -1700,8 +1714,8 @@ e1000_configure_rx(struct e1000_adapter *adapter)
 
                         /* Enable 82571 IPv4 payload checksum for UDP fragments
                          * Must be used in conjunction with packet-split. */
-                        if((adapter->hw.mac_type > e1000_82547_rev_2) && 
-                           (adapter->rx_ps)) {
+                        if ((hw->mac_type >= e1000_82571) && 
+                           (adapter->rx_ps_pages)) {
                                 rxcsum |= E1000_RXCSUM_IPPCSE;
                         }
                 } else {
@@ -1906,7 +1920,7 @@ e1000_clean_rx_ring(struct e1000_adapter *adapter,
                         dev_kfree_skb(buffer_info->skb);
                         buffer_info->skb = NULL;
 
-                        for(j = 0; j < PS_PAGE_BUFFERS; j++) {
+                        for(j = 0; j < adapter->rx_ps_pages; j++) {
                                 if(!ps_page->ps_page[j]) break;
                                 pci_unmap_single(pdev,
                                                  ps_page_dma->ps_page_dma[j],
@@ -3551,7 +3565,7 @@ e1000_clean_rx_irq_ps(struct e1000_adapter *adapter,
                 /* Good Receive */
                 skb_put(skb, length);
 
-                for(j = 0; j < PS_PAGE_BUFFERS; j++) {
+                for(j = 0; j < adapter->rx_ps_pages; j++) {
                         if(!(length = le16_to_cpu(rx_desc->wb.upper.length[j])))
                                 break;
 
@@ -3572,11 +3586,13 @@ e1000_clean_rx_irq_ps(struct e1000_adapter *adapter,
                                   rx_desc->wb.lower.hi_dword.csum_ip.csum, skb);
                 skb->protocol = eth_type_trans(skb, netdev);
 
-#ifdef HAVE_RX_ZERO_COPY
                 if(likely(rx_desc->wb.upper.header_status &
-                          E1000_RXDPS_HDRSTAT_HDRSP))
+                          E1000_RXDPS_HDRSTAT_HDRSP)) {
+                        adapter->rx_hdr_split++;
+#ifdef HAVE_RX_ZERO_COPY
                         skb_shinfo(skb)->zero_copy = TRUE;
 #endif
+                }
 #ifdef CONFIG_E1000_NAPI
                 if(unlikely(adapter->vlgrp && (staterr & E1000_RXD_STAT_VP))) {
                         vlan_hwaccel_receive_skb(skb, adapter->vlgrp,
@@ -3740,22 +3756,26 @@ e1000_alloc_rx_buffers_ps(struct e1000_adapter *adapter,
                 rx_desc = E1000_RX_DESC_PS(*rx_ring, i);
 
                 for(j = 0; j < PS_PAGE_BUFFERS; j++) {
-                        if(unlikely(!ps_page->ps_page[j])) {
-                                ps_page->ps_page[j] =
-                                        alloc_page(GFP_ATOMIC);
-                                if(unlikely(!ps_page->ps_page[j]))
-                                        goto no_buffers;
-                                ps_page_dma->ps_page_dma[j] =
-                                        pci_map_page(pdev,
-                                                     ps_page->ps_page[j],
-                                                     0, PAGE_SIZE,
-                                                     PCI_DMA_FROMDEVICE);
-                        }
-                        /* Refresh the desc even if buffer_addrs didn't
-                         * change because each write-back erases this info.
-                         */
-                        rx_desc->read.buffer_addr[j+1] =
-                                cpu_to_le64(ps_page_dma->ps_page_dma[j]);
+                        if (j < adapter->rx_ps_pages) {
+                                if (likely(!ps_page->ps_page[j])) {
+                                        ps_page->ps_page[j] =
+                                                alloc_page(GFP_ATOMIC);
+                                        if (unlikely(!ps_page->ps_page[j]))
+                                                goto no_buffers;
+                                        ps_page_dma->ps_page_dma[j] =
+                                                pci_map_page(pdev,
+                                                            ps_page->ps_page[j],
+                                                            0, PAGE_SIZE,
+                                                            PCI_DMA_FROMDEVICE);
+                                }
+                                /* Refresh the desc even if buffer_addrs didn't
+                                 * change because each write-back erases 
+                                 * this info.
+                                 */
+                                rx_desc->read.buffer_addr[j+1] =
+                                     cpu_to_le64(ps_page_dma->ps_page_dma[j]);
+                        } else
+                                rx_desc->read.buffer_addr[j+1] = ~0;
                 }
 
                 skb = dev_alloc_skb(adapter->rx_ps_bsize0 + NET_IP_ALIGN);