queue-6.6/net-ravb-always-process-tx-descriptor-ring.patch

   1 From 3cf1fec3a3cf24eb22bd8136e2214736d2ca22ed Mon Sep 17 00:00:00 2001
   2 From: Sasha Levin <sashal@kernel.org>
   3 Date: Tue, 2 Apr 2024 15:53:04 +0100
   4 Subject: net: ravb: Always process TX descriptor ring
   5
   6 From: Paul Barker <paul.barker.ct@bp.renesas.com>
   7
   8 [ Upstream commit 596a4254915f94c927217fe09c33a6828f33fb25 ]
   9
  10 The TX queue should be serviced each time the poll function is called,
  11 even if the full RX work budget has been consumed. This prevents
  12 starvation of the TX queue when RX bandwidth usage is high.
  13
  14 Fixes: c156633f1353 ("Renesas Ethernet AVB driver proper")
  15 Signed-off-by: Paul Barker <paul.barker.ct@bp.renesas.com>
  16 Reviewed-by: Sergey Shtylyov <s.shtylyov@omp.ru>
  17 Link: https://lore.kernel.org/r/20240402145305.82148-1-paul.barker.ct@bp.renesas.com
  18 Signed-off-by: Paolo Abeni <pabeni@redhat.com>
  19 Signed-off-by: Sasha Levin <sashal@kernel.org>
  20 ---
  21  drivers/net/ethernet/renesas/ravb_main.c | 7 +++++--
  22  1 file changed, 5 insertions(+), 2 deletions(-)
  23
  24 diff --git a/drivers/net/ethernet/renesas/ravb_main.c b/drivers/net/ethernet/renesas/ravb_main.c
  25 index b87e9252ea176..14595d23b1903 100644
  26 --- a/drivers/net/ethernet/renesas/ravb_main.c
  27 +++ b/drivers/net/ethernet/renesas/ravb_main.c
  28 @@ -1292,12 +1292,12 @@ static int ravb_poll(struct napi_struct *napi, int budget)
  29         int q = napi - priv->napi;
  30         int mask = BIT(q);
  31         int quota = budget;
  32 +       bool unmask;
  33
  34         /* Processing RX Descriptor Ring */
  35         /* Clear RX interrupt */
  36         ravb_write(ndev, ~(mask | RIS0_RESERVED), RIS0);
  37 -       if (ravb_rx(ndev, &quota, q))
  38 -               goto out;
  39 +       unmask = !ravb_rx(ndev, &quota, q);
  40
  41         /* Processing TX Descriptor Ring */
  42         spin_lock_irqsave(&priv->lock, flags);
  43 @@ -1307,6 +1307,9 @@ static int ravb_poll(struct napi_struct *napi, int budget)
  44         netif_wake_subqueue(ndev, q);
  45         spin_unlock_irqrestore(&priv->lock, flags);
  46
  47 +       if (!unmask)
  48 +               goto out;
  49 +
  50         napi_complete(napi);
  51
  52         /* Re-enable RX/TX interrupts */
  53 --
  54 2.43.0
  55