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(93-34-89-13.ip49.fastwebnet.it. [93.34.89.13]) by smtp.gmail.com with ESMTPSA id h9-20020a5d5489000000b003179d5aee67sm2231805wrv.94.2023.10.06.11.52.54 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 06 Oct 2023 11:52:57 -0700 (PDT) Message-ID: <65205789.5d0a0220.7e49b.ccb0@mx.google.com> X-Google-Original-Message-ID: Date: Fri, 6 Oct 2023 20:52:57 +0200 From: Christian Marangi To: Eric Dumazet Cc: Jakub Kicinski , Jason Gunthorpe , Leon Romanovsky , Wolfgang Grandegger , Marc Kleine-Budde , "David S. Miller" , Paolo Abeni , Chris Snook , Raju Rangoju , Jeroen de Borst , Praveen Kaligineedi , Shailend Chand , Douglas Miller , Michael Ellerman , Nicholas Piggin , Christophe Leroy , Nick Child , Haren Myneni , Rick Lindsley , Dany Madden , Thomas Falcon , Tariq Toukan , Alexandre Torgue , Jose Abreu , Maxime Coquelin , Krzysztof Halasa , Kalle Valo , Jeff Johnson , Gregory Greenman , Chandrashekar Devegowda , Intel Corporation , Chiranjeevi Rapolu , Liu Haijun , M Chetan Kumar , Ricardo Martinez , Loic Poulain , Sergey Ryazanov , Johannes Berg , Yuanjun Gong , Simon Horman , Rob Herring , Ziwei Xiao , Rushil Gupta , Coco Li , Thomas Gleixner , Junfeng Guo , Uwe =?iso-8859-1?Q?Kleine-K=F6nig?= , Wei Fang , Krzysztof Kozlowski , Yuri Karpov , Zhengchao Shao , Andrew Lunn , Zheng Zengkai , Lee Jones , Maximilian Luz , "Rafael J. Wysocki" , Dawei Li , Anjaneyulu , Benjamin Berg , linux-rdma@vger.kernel.org, linux-kernel@vger.kernel.org, linux-can@vger.kernel.org, netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-stm32@st-md-mailman.stormreply.com, linux-arm-kernel@lists.infradead.org, ath10k@lists.infradead.org, linux-wireless@vger.kernel.org Subject: Re: [net-next PATCH v2 3/4] netdev: replace napi_reschedule with napi_schedule References: <20231003145150.2498-1-ansuelsmth@gmail.com> <20231003145150.2498-3-ansuelsmth@gmail.com> <20231005093253.2e25533a@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: Precedence: bulk List-ID: X-Mailing-List: linux-can@vger.kernel.org On Thu, Oct 05, 2023 at 06:41:03PM +0200, Eric Dumazet wrote: > On Thu, Oct 5, 2023 at 6:32 PM Jakub Kicinski 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); Ehhh problem is that this is a simple rename so if any race is present, it's already there and not caused by this rename :( Don't know maybe this is out of scope and should be investigated with a bug report? Maybe this should be changed to prep/__schedule to prevent any kind of race? But doing so doesn't prevent any kind of ""starving""? -- Ansuel