[PATCH 5.11 549/601] net: renesas: ravb: Fix a stuck issue when a lot of frames are received

Greg Kroah-Hartman
2021-05-12T17:56:50Z

From: Yoshihiro Shimoda <yoshihiro.shimoda.uh@renesas.com>

[ 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@renesas.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/renesas/ravb_main.c | 35 ++++++++----------------
1 file changed, 12 insertions(+), 23 deletions(-)

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);

--
2.30.2