KS8695: update ksp->next_rx_desc_read at the end of rx loop
Yegor Yefremov [Sat, 20 Mar 2010 05:43:29 +0000 (22:43 -0700)]
There is no need to adjust the next rx descriptor after each packet,
so do it only once at the end of the routine.

Signed-off-by: Eric Dumazet <eric.dumazet@gmail.com>
Signed-off-by: Yegor Yefremov <yegorslists@googlemail.com>

drivers/net/arm/ks8695net.c

index a1d4188..e7810b7 100644 (file)
@@ -449,11 +449,10 @@ ks8695_rx_irq(int irq, void *dev_id)
 }
 
 /**
- *     ks8695_rx - Receive packets  called by NAPI poll method
+ *     ks8695_rx - Receive packets called by NAPI poll method
  *     @ksp: Private data for the KS8695 Ethernet
- *     @budget: The max packets would be receive
+ *     @budget: Number of packets allowed to process
  */
-
 static int ks8695_rx(struct ks8695_priv *ksp, int budget)
 {
        struct net_device *ndev = ksp->ndev;
@@ -461,7 +460,6 @@ static int ks8695_rx(struct ks8695_priv *ksp, int budget)
        int buff_n;
        u32 flags;
        int pktlen;
-       int last_rx_processed = -1;
        int received = 0;
 
        buff_n = ksp->next_rx_desc_read;
@@ -471,6 +469,7 @@ static int ks8695_rx(struct ks8695_priv *ksp, int budget)
                                        cpu_to_le32(RDES_OWN)))) {
                        rmb();
                        flags = le32_to_cpu(ksp->rx_ring[buff_n].status);
+
                        /* Found an SKB which we own, this means we
                         * received a packet
                         */
@@ -533,23 +532,18 @@ rx_failure:
                        ksp->rx_ring[buff_n].status = cpu_to_le32(RDES_OWN);
 rx_finished:
                        received++;
-                       /* And note this as processed so we can start
-                        * from here next time
-                        */
-                       last_rx_processed = buff_n;
                        buff_n = (buff_n + 1) & MAX_RX_DESC_MASK;
-                       /*And note which RX descriptor we last did */
-                       if (likely(last_rx_processed != -1))
-                               ksp->next_rx_desc_read =
-                                       (last_rx_processed + 1) &
-                                       MAX_RX_DESC_MASK;
        }
+
+       /* And note which RX descriptor we last did */
+       ksp->next_rx_desc_read = buff_n;
+
        /* And refill the buffers */
        ks8695_refill_rxbuffers(ksp);
 
-       /* Kick the RX DMA engine, in case it became
-        *  suspended */
+       /* Kick the RX DMA engine, in case it became suspended */
        ks8695_writereg(ksp, KS8695_DRSC, 0);
+
        return received;
 }