linux-kernel - Re: [net-next PATCH v2 3/4] netdev: replace napi_reschedule with napi

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Message-ID: <CANn89iJQ50AdXP2C1YB2pGjE02WCJ-QCsZqE1yGXtcGsfLA0Jw@mail.gmail.com>
Date:   Thu, 5 Oct 2023 18:41:03 +0200
From:   Eric Dumazet <edumazet@...gle.com>
To:     Jakub Kicinski <kuba@...nel.org>
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Subject: Re: [net-next PATCH v2 3/4] netdev: replace napi_reschedule with napi_schedule

On Thu, Oct 5, 2023 at 6:32 PM Jakub Kicinski <kuba@...nel.org> wrote:
>
> On Thu, 5 Oct 2023 18:11:56 +0200 Eric Dumazet wrote:
> > OK, but I suspect some users of napi_reschedule() might not be race-free...
>
> What's the race you're thinking of?

This sort of thing... the race is in fl_starving() though...

diff --git a/drivers/net/ethernet/chelsio/cxgb4/sge.c
b/drivers/net/ethernet/chelsio/cxgb4/sge.c
index 98dd78551d89..b5ff2e1a9975 100644
--- a/drivers/net/ethernet/chelsio/cxgb4/sge.c
+++ b/drivers/net/ethernet/chelsio/cxgb4/sge.c
@@ -4261,7 +4261,7 @@ static void sge_rx_timer_cb(struct timer_list *t)

                        if (fl_starving(adap, fl)) {
                                rxq = container_of(fl, struct sge_eth_rxq, fl);
-                               if (napi_reschedule(&rxq->rspq.napi))
+                               if (napi_schedule(&rxq->rspq.napi))
                                        fl->starving++;
                                else
                                        set_bit(id, s->starving_fl);