[PATCH 5.4 164/215] net: ravb: Always process TX descriptor ring

Greg Kroah-Hartman
2024-04-11T10:22:01Z

From: Paul Barker <paul.barker.ct@bp.renesas.com>

[ Upstream commit 596a4254915f94c927217fe09c33a6828f33fb25 ]

The TX queue should be serviced each time the poll function is called,
even if the full RX work budget has been consumed. This prevents
starvation of the TX queue when RX bandwidth usage is high.

Fixes: c156633f1353 ("Renesas Ethernet AVB driver proper")
Signed-off-by: Paul Barker <paul.barker.ct@bp.renesas.com>
Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
Link: https://lore.kernel.org/r/20240402145305.82148-1-paul.barker.ct@bp.renesas.com
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/ethernet/renesas/ravb_main.c | 7 +++++--
1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
index 53b9c77c7f6a7..3cc312a526d9b 100644
--- a/drivers/net/ethernet/renesas/ravb_main.c
+++ b/drivers/net/ethernet/renesas/ravb_main.c
@@ -911,12 +911,12 @@ static int ravb_poll(struct napi_struct *napi, int budget)
int q = napi - priv->napi;
int mask = BIT(q);
int quota = budget;
+ bool unmask;

/* Processing RX Descriptor Ring */
/* Clear RX interrupt */
ravb_write(ndev, ~(mask | RIS0_RESERVED), RIS0);
- if (ravb_rx(ndev, &quota, q))
- goto out;
+ unmask = !ravb_rx(ndev, &quota, q);

/* Processing RX Descriptor Ring */
spin_lock_irqsave(&priv->lock, flags);
@@ -926,6 +926,9 @@ static int ravb_poll(struct napi_struct *napi, int budget)
netif_wake_subqueue(ndev, q);
spin_unlock_irqrestore(&priv->lock, flags);

+ if (!unmask)
+ goto out;
+
napi_complete(napi);

/* Re-enable RX/TX interrupts */
--
2.43.0