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Wed, 27 Nov 2019 22:28:57 +0300 (MSK) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Date: Wed, 27 Nov 2019 22:28:57 +0300 From: Alexander Lobakin To: David Miller Cc: ecree@solarflare.com, jiri@mellanox.com, edumazet@google.com, idosch@mellanox.com, pabeni@redhat.com, petrm@mellanox.com, sd@queasysnail.net, f.fainelli@gmail.com, jaswinder.singh@linaro.org, manishc@marvell.com, GR-Linux-NIC-Dev@marvell.com, johannes.berg@intel.com, emmanuel.grumbach@intel.com, luciano.coelho@intel.com, linuxwifi@intel.com, kvalo@codeaurora.org, nicholas.johnson-opensource@outlook.com.au, kenny@panix.com, netdev@vger.kernel.org, linux-wireless@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH net] net: wireless: intel: iwlwifi: fix GRO_NORMAL packet stalling In-Reply-To: <20191127.112310.1018809619618803508.davem@davemloft.net> References: <20191127094123.18161-1-alobakin@dlink.ru> <20191127.112310.1018809619618803508.davem@davemloft.net> User-Agent: Roundcube Webmail/1.4.0 Message-ID: <717aa19f01da2bc36fd22343bbbc39f7@dlink.ru> X-Sender: alobakin@dlink.ru Sender: linux-wireless-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-wireless@vger.kernel.org David Miller wrote 27.11.2019 22:23: > From: Alexander Lobakin > Date: Wed, 27 Nov 2019 12:41:23 +0300 > >> Commit 6570bc79c0df ("net: core: use listified Rx for GRO_NORMAL in >> napi_gro_receive()") has applied batched GRO_NORMAL packets processing >> to all napi_gro_receive() users, including mac80211-based drivers. >> >> However, this change has led to a regression in iwlwifi driver [1][2] >> as >> it is required for NAPI users to call napi_complete_done() or >> napi_complete() and the end of every polling iteration, whilst iwlwifi >> doesn't use NAPI scheduling at all and just calls napi_gro_flush(). >> In that particular case, packets which have not been already flushed >> from napi->rx_list stall in it until at least next Rx cycle. >> >> Fix this by adding a manual flushing of the list to iwlwifi driver >> right >> before napi_gro_flush() call to mimic napi_complete() logics. >> >> I prefer to open-code gro_normal_list() rather than exporting it for 2 >> reasons: >> * to prevent from using it and napi_gro_flush() in any new drivers, >> as it is the *really* bad way to use NAPI that should be avoided; >> * to keep gro_normal_list() static and don't lose any CC >> optimizations. >> >> I also don't add the "Fixes:" tag as the mentioned commit was only a >> trigger that only exposed an improper usage of NAPI in this particular >> driver. >> >> [1] >> https://lore.kernel.org/netdev/PSXP216MB04388962C411CD0B17A86F47804A0@PSXP216MB0438.KORP216.PROD.OUTLOOK.COM >> [2] https://bugzilla.kernel.org/show_bug.cgi?id=205647 >> >> Signed-off-by: Alexander Lobakin > > Applied, thanks for the quick turnaround. Thank you all folks! Regards, ᚷ ᛖ ᚢ ᚦ ᚠ ᚱ