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[73.241.150.58]) by smtp.gmail.com with ESMTPSA id g17sm18947183pjl.37.2020.08.17.17.48.52 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Mon, 17 Aug 2020 17:48:53 -0700 (PDT) Subject: Re: [PATCH 3/3] net: lantiq: Use napi_complete_done() To: Eric Dumazet , Hauke Mehrtens , davem@davemloft.net Cc: kuba@kernel.org, netdev@vger.kernel.org, martin.blumenstingl@googlemail.com References: <20200815183314.404-1-hauke@hauke-m.de> <20200815183314.404-3-hauke@hauke-m.de> <17761534-65b1-e575-5e00-55e6f7e3f7b7@gmail.com> <718dce81-ace3-aaad-0f81-e75e227cd722@hauke-m.de> <28b6bd3f-761c-9143-e90d-30af5d76e3ed@gmail.com> From: Eric Dumazet Message-ID: <4d9fb110-f5b9-c279-6bac-d7663c8111b8@gmail.com> Date: Mon, 17 Aug 2020 17:48:52 -0700 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.11.0 MIME-Version: 1.0 In-Reply-To: <28b6bd3f-761c-9143-e90d-30af5d76e3ed@gmail.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 8/17/20 5:33 PM, Eric Dumazet wrote: > > > On 8/17/20 2:17 PM, Hauke Mehrtens wrote: >> On 8/16/20 8:07 PM, Eric Dumazet wrote: >>> >>> >>> On 8/15/20 11:33 AM, Hauke Mehrtens wrote: >>>> Use napi_complete_done() and activate the interrupts when this function >>>> returns true. This way the generic NAPI code can take care of activating >>>> the interrupts. >>>> >>>> Signed-off-by: Hauke Mehrtens >>>> --- >>>> drivers/net/ethernet/lantiq_xrx200.c | 8 ++------ >>>> 1 file changed, 2 insertions(+), 6 deletions(-) >>>> >>>> diff --git a/drivers/net/ethernet/lantiq_xrx200.c b/drivers/net/ethernet/lantiq_xrx200.c >>>> index f34e4dc8c661..674ffb2ecd9a 100644 >>>> --- a/drivers/net/ethernet/lantiq_xrx200.c >>>> +++ b/drivers/net/ethernet/lantiq_xrx200.c >>>> @@ -229,10 +229,8 @@ static int xrx200_poll_rx(struct napi_struct *napi, int budget) >>>> } >>>> } >>>> >>>> - if (rx < budget) { >>>> - napi_complete(&ch->napi); >>>> + if (napi_complete_done(&ch->napi, rx)) >>>> ltq_dma_enable_irq(&ch->dma); >>>> - } >>>> >>>> return rx; >>>> } >>>> @@ -271,10 +269,8 @@ static int xrx200_tx_housekeeping(struct napi_struct *napi, int budget) >>>> if (netif_queue_stopped(net_dev)) >>>> netif_wake_queue(net_dev); >>>> >>>> - if (pkts < budget) { >>>> - napi_complete(&ch->napi); >>>> + if (napi_complete_done(&ch->napi, pkts)) >>>> ltq_dma_enable_irq(&ch->dma); >>>> - } >>>> >>>> return pkts; >>>> } >>>> >>> >>> >>> This looks buggy to me. >> >> Hi Eric, >> >> Thanks for looking at the patch. >> >> What exactly looks buggy to you? > > You removed the " if (rx < budget) " > > But you must not. > > Drivers have to keep the test. > > Something like that seems more correct : > > diff --git a/drivers/net/ethernet/lantiq_xrx200.c b/drivers/net/ethernet/lantiq_xrx200.c > index 1645e4e7ebdbb3c7abff8fe4207273df20f123d4..e3d617d387ed0f5593c3ba81d1d531d463bb5a6e 100644 > --- a/drivers/net/ethernet/lantiq_xrx200.c > +++ b/drivers/net/ethernet/lantiq_xrx200.c > @@ -230,8 +230,8 @@ static int xrx200_poll_rx(struct napi_struct *napi, int budget) > } > > if (rx < budget) { > - napi_complete(&ch->napi); > - ltq_dma_enable_irq(&ch->dma); > + if (napi_complete(&ch->napi, rx)) Obviously : s/napi_complete/napi_complete_done/ > + ltq_dma_enable_irq(&ch->dma); > } > > return rx; > @@ -269,8 +269,8 @@ static int xrx200_tx_housekeeping(struct napi_struct *napi, int budget) > netdev_completed_queue(ch->priv->net_dev, pkts, bytes); > > if (pkts < budget) { > - napi_complete(&ch->napi); > - ltq_dma_enable_irq(&ch->dma); > + if (napi_complete(&ch->napi, pkts)) Same : s/napi_complete/napi_complete_done/ > + ltq_dma_enable_irq(&ch->dma); > } > > return pkts; >