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Tue, 17 Mar 2026 02:57:40 -0700 (PDT) Received: from [192.168.88.32] ([216.128.11.95]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-439fe1affe9sm51534817f8f.15.2026.03.17.02.57.39 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 17 Mar 2026 02:57:40 -0700 (PDT) Message-ID: <7b082017-5245-434c-9668-49b630af6484@redhat.com> Date: Tue, 17 Mar 2026 10:57:38 +0100 Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net-next 2/2] ppp: remove pch->chan NULL checks from tx path To: Qingfang Deng , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , linux-ppp@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Cc: Paul Mackerras References: <20260312093732.277254-1-dqfext@gmail.com> <20260312093732.277254-2-dqfext@gmail.com> Content-Language: en-US From: Paolo Abeni In-Reply-To: <20260312093732.277254-2-dqfext@gmail.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit On 3/12/26 10:37 AM, Qingfang Deng wrote: > Now that ppp_disconnect_channel() is called before pch->chan is set to > NULL, a channel from ppp->channels list on the transmit path is > guaranteed to have non-NULL pch->chan. > > Remove the pch->chan NULL checks from ppp_push(), ppp_mp_explode(), and > ppp_fill_forward_path(), where a channel is obtained from the list. > Remove the corresponding WRITE/READ_ONCE annotations as they no longer > race. > > Signed-off-by: Qingfang Deng Looks sane to me. It looks like you are investing a significant amount of effort to improve the ppp driver. I strongly suggest you to create some functional self-tests before any other changes in this area. The code is pretty intricate and obscure, a reasonable code coverage could add significant confidence in non trivial changes, and could possibly help revisiting/cleaning-up the locking schema (which is AFAICS the most significant pain-point). /P