Patch "net: renesas: ravb: Fix a stuck issue when a lot of frames are received" has been added to the 5.10-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

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

to the 5.10-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     net-renesas-ravb-fix-a-stuck-issue-when-a-lot-of-fra.patch
and it can be found in the queue-5.10 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 1b5d0e5e82e2d754ad3be2fe7606d018b977517f
Author: Yoshihiro Shimoda <yoshihiro.shimoda.uh@xxxxxxxxxxx>
Date:   Wed Apr 21 13:52:46 2021 +0900

    net: renesas: ravb: Fix a stuck issue when a lot of frames are received
    
    [ Upstream commit 5718458b092bf6bf4482c5df32affba3c3259517 ]
    
    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@xxxxxxxxxxx>
    Signed-off-by: David S. Miller <davem@xxxxxxxxxxxxx>
    Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>

diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index bd30505fbc57..f96eed67e1a2 100644
--- 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);