[SKY2]: status polling loop (post merge)

Handle the corner case where budget is exhausted correctly.
And save unnecessary read of index register.

Signed-off-by: Stephen Hemminger <shemminger@linux-foundation.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/sky2.c b/drivers/net/sky2.c
index 4e569fa0f96c3bcd413099bcd27cb39083aa9618..0a3203465415fafda51abd5be2ecd19d436412c1 100644 (file)
--- a/drivers/net/sky2.c
+++ b/drivers/net/sky2.c
@@ -2245,15 +2245,13 @@ static inline void sky2_tx_done(struct net_device *dev, u16 last)
 }
 
 /* Process status response ring */
-static int sky2_status_intr(struct sky2_hw *hw, int to_do)
+static int sky2_status_intr(struct sky2_hw *hw, int to_do, u16 idx)
 {
        int work_done = 0;
        unsigned rx[2] = { 0, 0 };
-       u16 hwidx = sky2_read16(hw, STAT_PUT_IDX);
 
        rmb();
-
-       while (hw->st_idx != hwidx) {
+       do {
                struct sky2_port *sky2;
                struct sky2_status_le *le  = hw->st_le + hw->st_idx;
                unsigned port = le->css & CSS_LINK_BIT;
@@ -2364,7 +2362,7 @@ static int sky2_status_intr(struct sky2_hw *hw, int to_do)
                                printk(KERN_WARNING PFX
                                       "unknown status opcode 0x%x\n", le->opcode);
                }
-       }
+       } while (hw->st_idx != idx);
 
        /* Fully processed status ring so clear irq */
        sky2_write32(hw, STAT_CTRL, SC_STAT_CLR_IRQ);
@@ -2607,6 +2605,7 @@ static int sky2_poll(struct napi_struct *napi, int work_limit)
        struct sky2_hw *hw = container_of(napi, struct sky2_hw, napi);
        u32 status = sky2_read32(hw, B0_Y2_SP_EISR);
        int work_done = 0;
+       u16 idx;
 
        if (unlikely(status & Y2_IS_ERROR))
                sky2_err_intr(hw, status);
@@ -2617,29 +2616,23 @@ static int sky2_poll(struct napi_struct *napi, int work_limit)
        if (status & Y2_IS_IRQ_PHY2)
                sky2_phy_intr(hw, 1);
 
-       for(;;) {
-               work_done += sky2_status_intr(hw, work_limit);
+       while ((idx = sky2_read16(hw, STAT_PUT_IDX)) != hw->st_idx) {
+               work_done += sky2_status_intr(hw, work_limit - work_done, idx);
 
                if (work_done >= work_limit)
-                       break;
-
-               /* More work? */
-               if (hw->st_idx != sky2_read16(hw, STAT_PUT_IDX))
-                       continue;
-
-               /* Bug/Errata workaround?
-                * Need to kick the TX irq moderation timer.
-                */
-               if (sky2_read8(hw, STAT_TX_TIMER_CTRL) == TIM_START) {
-                       sky2_write8(hw, STAT_TX_TIMER_CTRL, TIM_STOP);
-                       sky2_write8(hw, STAT_TX_TIMER_CTRL, TIM_START);
-               }
-
-               napi_complete(napi);
-               sky2_read32(hw, B0_Y2_SP_LISR);
-               break;
+                       goto done;
+       }
 
+       /* Bug/Errata workaround?
+        * Need to kick the TX irq moderation timer.
+        */
+       if (sky2_read8(hw, STAT_TX_TIMER_CTRL) == TIM_START) {
+               sky2_write8(hw, STAT_TX_TIMER_CTRL, TIM_STOP);
+               sky2_write8(hw, STAT_TX_TIMER_CTRL, TIM_START);
        }
+       napi_complete(napi);
+       sky2_read32(hw, B0_Y2_SP_LISR);
+done:
 
        return work_done;
 }