sh_eth: Optimization for RX excess judgement

Both of 'boguscnt' and 'quota' have nearly meaning as the condition of
the reception loop.
In order to cut down redundant processing, this patch changes excess
judgement.

Signed-off-by: Mitsuhiro Kimura <mitsuhiro.kimura.kc@renesas.com>
Signed-off-by: Yoshihiro Kaneko <ykaneko0929@gmail.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/renesas/sh_eth.c b/drivers/net/ethernet/renesas/sh_eth.c
index 71f59ee513046defd7f4334c13c9a2675cac0af7..e77025915b235cff096fadb60f61d38d6d2da638 100644 (file)
--- a/drivers/net/ethernet/renesas/sh_eth.c
+++ b/drivers/net/ethernet/renesas/sh_eth.c
@@ -1395,10 +1395,13 @@ static int sh_eth_rx(struct net_device *ndev, u32 intr_status, int *quota)
 
        int entry = mdp->cur_rx % mdp->num_rx_ring;
        int boguscnt = (mdp->dirty_rx + mdp->num_rx_ring) - mdp->cur_rx;
+       int limit;
        struct sk_buff *skb;
        u16 pkt_len = 0;
        u32 desc_status;
 
+       boguscnt = min(boguscnt, *quota);
+       limit = boguscnt;
        rxdesc = &mdp->rx_ring[entry];
        while (!(rxdesc->status & cpu_to_edmac(mdp, RD_RACT))) {
                desc_status = edmac_to_cpu(mdp, rxdesc->status);
@@ -1407,11 +1410,6 @@ static int sh_eth_rx(struct net_device *ndev, u32 intr_status, int *quota)
                if (--boguscnt < 0)
                        break;
 
-               if (*quota <= 0)
-                       break;
-
-               (*quota)--;
-
                if (!(desc_status & RDFEND))
                        ndev->stats.rx_length_errors++;
 
@@ -1502,6 +1500,8 @@ static int sh_eth_rx(struct net_device *ndev, u32 intr_status, int *quota)
                sh_eth_write(ndev, EDRRR_R, EDRRR);
        }
 
+       *quota -= limit - boguscnt - 1;
+
        return *quota <= 0;
 }