1 files changed, 23 insertions, 25 deletions

diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index 46c3b1f9ff89..d01a099475a1 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -3517,6 +3517,15 @@ void e1000e_reset(struct e1000_adapter *adapter)
         }
 
         /*
+         * Alignment of Tx data is on an arbitrary byte boundary with the
+         * maximum size per Tx descriptor limited only to the transmit
+         * allocation of the packet buffer minus 96 bytes with an upper
+         * limit of 24KB due to receive synchronization limitations.
+         */
+        adapter->tx_fifo_limit = min_t(u32, ((er32(PBA) >> 16) << 10) - 96,
+                                       24 << 10);
+
+        /*
          * Disable Adaptive Interrupt Moderation if 2 full packets cannot
          * fit in receive buffer.
          */
@@ -4785,12 +4794,9 @@ static bool e1000_tx_csum(struct e1000_ring *tx_ring, struct sk_buff *skb)
         return 1;
 }
 
-#define E1000_MAX_PER_TXD       8192
-#define E1000_MAX_TXD_PWR       12
-
 static int e1000_tx_map(struct e1000_ring *tx_ring, struct sk_buff *skb,
                         unsigned int first, unsigned int max_per_txd,
-                        unsigned int nr_frags, unsigned int mss)
+                        unsigned int nr_frags)
 {
         struct e1000_adapter *adapter = tx_ring->adapter;
         struct pci_dev *pdev = adapter->pdev;
@@ -5023,20 +5029,19 @@ static int __e1000_maybe_stop_tx(struct e1000_ring *tx_ring, int size)
 
 static int e1000_maybe_stop_tx(struct e1000_ring *tx_ring, int size)
 {
+        BUG_ON(size > tx_ring->count);
+
         if (e1000_desc_unused(tx_ring) >= size)
                 return 0;
         return __e1000_maybe_stop_tx(tx_ring, size);
 }
 
-#define TXD_USE_COUNT(S, X) (((S) >> (X)) + 1)
 static netdev_tx_t e1000_xmit_frame(struct sk_buff *skb,
                                     struct net_device *netdev)
 {
         struct e1000_adapter *adapter = netdev_priv(netdev);
         struct e1000_ring *tx_ring = adapter->tx_ring;
         unsigned int first;
-        unsigned int max_per_txd = E1000_MAX_PER_TXD;
-        unsigned int max_txd_pwr = E1000_MAX_TXD_PWR;
         unsigned int tx_flags = 0;
         unsigned int len = skb_headlen(skb);
         unsigned int nr_frags;
@@ -5056,18 +5061,8 @@ static netdev_tx_t e1000_xmit_frame(struct sk_buff *skb,
         }
 
         mss = skb_shinfo(skb)->gso_size;
-        /*
-         * The controller does a simple calculation to
-         * make sure there is enough room in the FIFO before
-         * initiating the DMA for each buffer.  The calc is:
-         * 4 = ceil(buffer len/mss).  To make sure we don't
-         * overrun the FIFO, adjust the max buffer len if mss
-         * drops.
-         */
         if (mss) {
                 u8 hdr_len;
-                max_per_txd = min(mss << 2, max_per_txd);
-                max_txd_pwr = fls(max_per_txd) - 1;
 
                 /*
                  * TSO Workaround for 82571/2/3 Controllers -- if skb->data
@@ -5097,12 +5092,12 @@ static netdev_tx_t e1000_xmit_frame(struct sk_buff *skb,
                 count++;
         count++;
 
-        count += TXD_USE_COUNT(len, max_txd_pwr);
+        count += DIV_ROUND_UP(len, adapter->tx_fifo_limit);
 
         nr_frags = skb_shinfo(skb)->nr_frags;
         for (f = 0; f < nr_frags; f++)
-                count += TXD_USE_COUNT(skb_frag_size(&skb_shinfo(skb)->frags[f]),
-                                       max_txd_pwr);
+                count += DIV_ROUND_UP(skb_frag_size(&skb_shinfo(skb)->frags[f]),
+                                      adapter->tx_fifo_limit);
 
         if (adapter->hw.mac.tx_pkt_filtering)
                 e1000_transfer_dhcp_info(adapter, skb);
@@ -5144,15 +5139,18 @@ static netdev_tx_t e1000_xmit_frame(struct sk_buff *skb,
                 tx_flags |= E1000_TX_FLAGS_NO_FCS;
 
         /* if count is 0 then mapping error has occurred */
-        count = e1000_tx_map(tx_ring, skb, first, max_per_txd, nr_frags, mss);
+        count = e1000_tx_map(tx_ring, skb, first, adapter->tx_fifo_limit,
+                             nr_frags);
         if (count) {
                 skb_tx_timestamp(skb);
 
                 netdev_sent_queue(netdev, skb->len);
                 e1000_tx_queue(tx_ring, tx_flags, count);
                 /* Make sure there is space in the ring for the next send. */
-                e1000_maybe_stop_tx(tx_ring, MAX_SKB_FRAGS + 2);
-
+                e1000_maybe_stop_tx(tx_ring,
+                                    (MAX_SKB_FRAGS *
+                                     DIV_ROUND_UP(PAGE_SIZE,
+                                                  adapter->tx_fifo_limit) + 2));
         } else {
                 dev_kfree_skb_any(skb);
                 tx_ring->buffer_info[first].time_stamp = 0;
@@ -6327,8 +6325,8 @@ static int __devinit e1000_probe(struct pci_dev *pdev,
         adapter->hw.phy.autoneg_advertised = 0x2f;
 
         /* ring size defaults */
-        adapter->rx_ring->count = 256;
-        adapter->tx_ring->count = 256;
+        adapter->rx_ring->count = E1000_DEFAULT_RXD;
+        adapter->tx_ring->count = E1000_DEFAULT_TXD;
 
         /*
          * Initial Wake on LAN setting - If APM wake is enabled in