net: renesas: ravb: Fix a stuck issue when a lot of frames are received

When a lot of frames were received in the short term, the driver
caused a stuck of receiving until a new frame was received. For example,
the following command from other device could cause this issue.

    $ sudo ping -f -l 1000 -c 1000 <this driver's ipaddress>

The previous code always cleared the interrupt flag of RX but checks
the interrupt flags in ravb_poll(). So, ravb_poll() could not call
ravb_rx() in the next time until a new RX frame was received if
ravb_rx() returned true. To fix the issue, always calls ravb_rx()
regardless the interrupt flags condition.

Fixes: c156633f1353 ("Renesas Ethernet AVB driver proper")
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/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index eb0c03b..cad57d5 100644 (file)
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -911,31 +911,20 @@ static int ravb_poll(struct napi_struct *napi, int budget)
        int q = napi - priv->napi;
        int mask = BIT(q);
        int quota = budget;
-       u32 ris0, tis;
 
-       for (;;) {
-               tis = ravb_read(ndev, TIS);
-               ris0 = ravb_read(ndev, RIS0);
-               if (!((ris0 & mask) || (tis & mask)))
-                       break;
+       /* Processing RX Descriptor Ring */
+       /* Clear RX interrupt */
+       ravb_write(ndev, ~(mask | RIS0_RESERVED), RIS0);
+       if (ravb_rx(ndev, &quota, q))
+               goto out;
 
-               /* Processing RX Descriptor Ring */
-               if (ris0 & mask) {
-                       /* Clear RX interrupt */
-                       ravb_write(ndev, ~(mask | RIS0_RESERVED), RIS0);
-                       if (ravb_rx(ndev, &quota, q))
-                               goto out;
-               }
-               /* Processing TX Descriptor Ring */
-               if (tis & mask) {
-                       spin_lock_irqsave(&priv->lock, flags);
-                       /* Clear TX interrupt */
-                       ravb_write(ndev, ~(mask | TIS_RESERVED), TIS);
-                       ravb_tx_free(ndev, q, true);
-                       netif_wake_subqueue(ndev, q);
-                       spin_unlock_irqrestore(&priv->lock, flags);
-               }
-       }
+       /* Processing RX Descriptor Ring */
+       spin_lock_irqsave(&priv->lock, flags);
+       /* Clear TX interrupt */
+       ravb_write(ndev, ~(mask | TIS_RESERVED), TIS);
+       ravb_tx_free(ndev, q, true);
+       netif_wake_subqueue(ndev, q);
+       spin_unlock_irqrestore(&priv->lock, flags);
 
        napi_complete(napi);