ftgmac100: Simplify rx pointer handling in the rx path

We don't handle fragmented RX packets, so the "looping"
helpers to locate the first segment of a packet or to
drop a packet aren't actually helping.

Take them out and simplify ftgmac100_rx_packet() further
as a result.

Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/faraday/ftgmac100.c b/drivers/net/ethernet/faraday/ftgmac100.c
index 82ab3676974c7e724699c9dbe0a7d08922b0eeab..44be11da9d64a011c86363ca89453b27269d3c61 100644 (file)
--- a/drivers/net/ethernet/faraday/ftgmac100.c
+++ b/drivers/net/ethernet/faraday/ftgmac100.c
@@ -431,34 +431,6 @@ static int ftgmac100_next_rx_pointer(int pointer)
        return (pointer + 1) & (RX_QUEUE_ENTRIES - 1);
 }
 
-static void ftgmac100_rx_pointer_advance(struct ftgmac100 *priv)
-{
-       priv->rx_pointer = ftgmac100_next_rx_pointer(priv->rx_pointer);
-}
-
-static struct ftgmac100_rxdes *ftgmac100_current_rxdes(struct ftgmac100 *priv)
-{
-       return &priv->descs->rxdes[priv->rx_pointer];
-}
-
-static struct ftgmac100_rxdes *
-ftgmac100_rx_locate_first_segment(struct ftgmac100 *priv)
-{
-       struct ftgmac100_rxdes *rxdes = ftgmac100_current_rxdes(priv);
-
-       while (ftgmac100_rxdes_packet_ready(rxdes)) {
-               if (ftgmac100_rxdes_first_segment(rxdes))
-                       return rxdes;
-
-               ftgmac100_rxdes_set_dma_own(priv, rxdes);
-               ftgmac100_rx_pointer_advance(priv);
-               rxdes = ftgmac100_current_rxdes(priv);
-       }
-
-       return NULL;
-}
-
-
 static void ftgmac100_rx_packet_error(struct ftgmac100 *priv,
                                      struct ftgmac100_rxdes *rxdes)
 {
@@ -476,51 +448,32 @@ static void ftgmac100_rx_packet_error(struct ftgmac100 *priv,
                netdev->stats.rx_length_errors++;
 }
 
-static void ftgmac100_rx_drop_packet(struct ftgmac100 *priv)
-{
-       struct net_device *netdev = priv->netdev;
-       struct ftgmac100_rxdes *rxdes = ftgmac100_current_rxdes(priv);
-       bool done = false;
-
-       if (net_ratelimit())
-               netdev_dbg(netdev, "drop packet %p\n", rxdes);
-
-       do {
-               if (ftgmac100_rxdes_last_segment(rxdes))
-                       done = true;
-
-               ftgmac100_rxdes_set_dma_own(priv, rxdes);
-               ftgmac100_rx_pointer_advance(priv);
-               rxdes = ftgmac100_current_rxdes(priv);
-       } while (!done && ftgmac100_rxdes_packet_ready(rxdes));
-
-       netdev->stats.rx_dropped++;
-}
-
 static bool ftgmac100_rx_packet(struct ftgmac100 *priv, int *processed)
 {
        struct net_device *netdev = priv->netdev;
        struct ftgmac100_rxdes *rxdes;
        struct sk_buff *skb;
        struct page *page;
-       unsigned int size;
+       unsigned int pointer, size;
        dma_addr_t map;
 
-       rxdes = ftgmac100_rx_locate_first_segment(priv);
-       if (!rxdes)
+       /* Grab next RX descriptor */
+       pointer = priv->rx_pointer;
+       rxdes = &priv->descs->rxdes[pointer];
+
+       /* Do we have a packet ? */
+       if (!ftgmac100_rxdes_packet_ready(rxdes))
                return false;
 
-       /* We don't support segmented rx frames, so drop these
-        * along with packets with errors.
-        */
-       if (unlikely(!ftgmac100_rxdes_last_segment(rxdes))) {
-               ftgmac100_rx_drop_packet(priv);
-               return true;
-       }
+       /* We don't cope with fragmented RX packets */
+       if (unlikely(!ftgmac100_rxdes_first_segment(rxdes) ||
+                    !ftgmac100_rxdes_last_segment(rxdes)))
+               goto drop;
+
+       /* Any error (other than csum offload) flagged ? */
        if (unlikely(ftgmac100_rxdes_any_error(rxdes))) {
                ftgmac100_rx_packet_error(priv, rxdes);
-               ftgmac100_rx_drop_packet(priv);
-               return true;
+               goto drop;
        }
 
        /* If the packet had no buffer (failed to allocate earlier)
@@ -529,8 +482,7 @@ static bool ftgmac100_rx_packet(struct ftgmac100 *priv, int *processed)
        page = ftgmac100_rxdes_get_page(priv, rxdes);
        if (!page) {
                ftgmac100_alloc_rx_page(priv, rxdes, GFP_ATOMIC);
-               ftgmac100_rx_pointer_advance(priv);
-               return true;
+               goto drop;
        }
 
        /* start processing */
@@ -538,9 +490,7 @@ static bool ftgmac100_rx_packet(struct ftgmac100 *priv, int *processed)
        if (unlikely(!skb)) {
                if (net_ratelimit())
                        netdev_err(netdev, "rx skb alloc failed\n");
-
-               ftgmac100_rx_drop_packet(priv);
-               return true;
+               goto drop;
        }
 
        if (unlikely(ftgmac100_rxdes_multicast(rxdes)))
@@ -577,8 +527,7 @@ static bool ftgmac100_rx_packet(struct ftgmac100 *priv, int *processed)
 
        ftgmac100_alloc_rx_page(priv, rxdes, GFP_ATOMIC);
 
-       ftgmac100_rx_pointer_advance(priv);
-       rxdes = ftgmac100_current_rxdes(priv);
+       priv->rx_pointer = ftgmac100_next_rx_pointer(pointer);
 
        /* Small frames are copied into linear part of skb to free one page */
        if (skb->len <= 128) {
@@ -601,6 +550,13 @@ static bool ftgmac100_rx_packet(struct ftgmac100 *priv, int *processed)
 
        (*processed)++;
        return true;
+
+ drop:
+       /* Clean rxdes0 (which resets own bit) */
+       rxdes->rxdes0 &= cpu_to_le32(priv->rxdes0_edorr_mask);
+       priv->rx_pointer = ftgmac100_next_rx_pointer(pointer);
+       netdev->stats.rx_dropped++;
+       return true;
 }
 
 static void ftgmac100_txdes_reset(const struct ftgmac100 *priv,