net: renesas: rswitch: Fix the output value of quote from rswitch_rx()

If the RX descriptor doesn't have any data, the output value of quote
from rswitch_rx() will be increased unexpectedily. So, fix it.

Reported-by: Volodymyr Babchuk <volodymyr_babchuk@epam.com>
Fixes: 3590918b5d07 ("net: ethernet: renesas: Add support for "Ethernet Switch"")
Signed-off-by: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ethernet/renesas/rswitch.c b/drivers/net/ethernet/renesas/rswitch.c
index 853394e..46d8d9c 100644 (file)
--- a/drivers/net/ethernet/renesas/rswitch.c
+++ b/drivers/net/ethernet/renesas/rswitch.c
@@ -702,13 +702,14 @@ static bool rswitch_rx(struct net_device *ndev, int *quota)
        u16 pkt_len;
        u32 get_ts;
 
+       if (*quota <= 0)
+               return true;
+
        boguscnt = min_t(int, gq->ring_size, *quota);
        limit = boguscnt;
 
        desc = &gq->rx_ring[gq->cur];
        while ((desc->desc.die_dt & DT_MASK) != DT_FEMPTY) {
-               if (--boguscnt < 0)
-                       break;
                dma_rmb();
                pkt_len = le16_to_cpu(desc->desc.info_ds) & RX_DS;
                skb = gq->skbs[gq->cur];
@@ -734,6 +735,9 @@ static bool rswitch_rx(struct net_device *ndev, int *quota)
 
                gq->cur = rswitch_next_queue_index(gq, true, 1);
                desc = &gq->rx_ring[gq->cur];
+
+               if (--boguscnt <= 0)
+                       break;
        }
 
        num = rswitch_get_num_cur_queues(gq);
@@ -745,7 +749,7 @@ static bool rswitch_rx(struct net_device *ndev, int *quota)
                goto err;
        gq->dirty = rswitch_next_queue_index(gq, false, num);
 
-       *quota -= limit - (++boguscnt);
+       *quota -= limit - boguscnt;
 
        return boguscnt <= 0;