[PATCH] sky2: fix NAPI and receive handling

Speed up the receive and interrupt processing and eliminate a
couple of race conditions from NAPI code.

Signed-off-by: Stephen Hemminger <shemminger@osdl.org>
Signed-off-by: Jeff Garzik <jgarzik@pobox.com>

diff --git a/drivers/net/sky2.c b/drivers/net/sky2.c
index 92d69fff875505daf651be490e01bf4ca1f3db1d..a85a8d16908f88b8eed6ae87d6a576475f6ac1e7 100644 (file)
--- a/drivers/net/sky2.c
+++ b/drivers/net/sky2.c
@@ -76,7 +76,7 @@
 
 #define RX_LE_SIZE             256
 #define RX_LE_BYTES            (RX_LE_SIZE*sizeof(struct sky2_rx_le))
-#define RX_MAX_PENDING         (RX_LE_SIZE/2 - 1)
+#define RX_MAX_PENDING         (RX_LE_SIZE/2 - 2)
 #define RX_DEF_PENDING         128
 #define RX_COPY_THRESHOLD      256
 
@@ -690,7 +690,7 @@ static inline void sky2_put_idx(struct sky2_hw *hw, unsigned q,
 setnew:
                sky2_write16(hw, Y2_QADDR(q, PREF_UNIT_PUT_IDX), idx);
        }
-       *last = sky2_read16(hw, Y2_QADDR(q, PREF_UNIT_PUT_IDX));
+       *last = idx;
 }
 
 
@@ -723,15 +723,6 @@ static inline void sky2_rx_add(struct sky2_port *sky2, struct ring_info *re)
        le->opcode = OP_PACKET | HW_OWNER;
 }
 
-/* Tell receiver about new buffers. */
-static inline void rx_set_put(struct net_device *dev)
-{
-       struct sky2_port *sky2 = netdev_priv(dev);
-
-       if (sky2->rx_last_put != sky2->rx_put)
-               sky2_put_idx(sky2->hw, rxqaddr[sky2->port], sky2->rx_put,
-                            &sky2->rx_last_put, RX_LE_SIZE);
-}
 
 /* Tell chip where to start receive checksum.
  * Actually has two checksums, but set both same to avoid possible byte
@@ -1616,6 +1607,10 @@ resubmit:
        re->skb->ip_summed = CHECKSUM_NONE;
        sky2_rx_add(sky2, re);
 
+       /* Tell receiver about new buffers. */
+       sky2_put_idx(sky2->hw, rxqaddr[sky2->port], sky2->rx_put,
+                    &sky2->rx_last_put, RX_LE_SIZE);
+
        return skb;
 
 error:
@@ -1664,16 +1659,26 @@ static int sky2_poll(struct net_device *dev0, int *budget)
        hwidx = sky2_read16(hw, STAT_PUT_IDX);
        BUG_ON(hwidx >= STATUS_RING_SIZE);
        rmb();
-       while (hw->st_idx != hwidx && work_done < to_do) {
+
+       do {
                struct sky2_status_le *le = hw->st_le + hw->st_idx;
                struct sky2_port *sky2;
                struct sk_buff *skb;
                u32 status;
                u16 length;
 
-               BUG_ON(le->link >= hw->ports);
-               if (!hw->dev[le->link])
-                       goto skip;
+               /* Are we done yet? */
+               if (hw->st_idx == hwidx) {
+                       sky2_write32(hw, STAT_CTRL, SC_STAT_CLR_IRQ);
+                       hwidx = sky2_read16(hw, STAT_PUT_IDX);
+                       if (hwidx == hw->st_idx)
+                               break;
+               }
+
+               hw->st_idx = (hw->st_idx + 1) % STATUS_RING_SIZE;
+               prefetch(&hw->st_le[hw->st_idx]);
+
+               BUG_ON(le->link >= hw->ports || !hw->dev[le->link]);
 
                sky2 = netdev_priv(hw->dev[le->link]);
                status = le32_to_cpu(le->status);
@@ -1692,6 +1697,7 @@ static int sky2_poll(struct net_device *dev0, int *budget)
                        } else
 #endif
                                netif_receive_skb(skb);
+                       ++work_done;
                        break;
 
 #ifdef SKY2_VLAN_TAG_USED
@@ -1722,22 +1728,11 @@ static int sky2_poll(struct net_device *dev0, int *budget)
                        break;
                }
 
-       skip:
-               hw->st_idx = (hw->st_idx + 1) % STATUS_RING_SIZE;
-               if (hw->st_idx == hwidx) {
-                       hwidx = sky2_read16(hw, STAT_PUT_IDX);
-                       rmb();
-               }
-       }
+               le->opcode = 0; /* paranoia */
+       } while (work_done < to_do);
 
        mmiowb();
 
-       if (hw->dev[0])
-               rx_set_put(hw->dev[0]);
-
-       if (hw->dev[1])
-               rx_set_put(hw->dev[1]);
-
        *budget -= work_done;
        dev0->quota -= work_done;
        if (work_done < to_do) {
@@ -1750,10 +1745,10 @@ static int sky2_poll(struct net_device *dev0, int *budget)
                        sky2_write8(hw, STAT_TX_TIMER_CTRL, TIM_START);
                }
 
+               netif_rx_complete(dev0);
                hw->intr_mask |= Y2_IS_STAT_BMU;
                sky2_write32(hw, B0_IMSK, hw->intr_mask);
                sky2_read32(hw, B0_IMSK);
-               netif_rx_complete(dev0);
        }
 
        return work_done >= to_do;
@@ -1880,6 +1875,7 @@ static void sky2_phy_intr(struct sky2_hw *hw, unsigned port)
 static irqreturn_t sky2_intr(int irq, void *dev_id, struct pt_regs *regs)
 {
        struct sky2_hw *hw = dev_id;
+       struct net_device *dev0 = hw->dev[0];
        u32 status;
 
        status = sky2_read32(hw, B0_Y2_SP_ISRC2);
@@ -1890,12 +1886,13 @@ static irqreturn_t sky2_intr(int irq, void *dev_id, struct pt_regs *regs)
                sky2_hw_intr(hw);
 
        /* Do NAPI for Rx and Tx status */
-       if ((status & Y2_IS_STAT_BMU) && netif_rx_schedule_test(hw->dev[0])) {
-               sky2_write32(hw, STAT_CTRL, SC_STAT_CLR_IRQ);
-
+       if (status & Y2_IS_STAT_BMU) {
                hw->intr_mask &= ~Y2_IS_STAT_BMU;
                sky2_write32(hw, B0_IMSK, hw->intr_mask);
-               __netif_rx_schedule(hw->dev[0]);
+               prefetch(&hw->st_le[hw->st_idx]);
+
+               if (netif_rx_schedule_test(dev0))
+                       __netif_rx_schedule(dev0);
        }
 
        if (status & Y2_IS_IRQ_PHY1)