From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.remote-ip=209.85.208.53 ARC-Seal: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; cv=none; t=1793136312; b=2qn7XLouw2S/pAuq4f8kHxrQa5Q/+MOrrSefcr5Ytc/uH0T4DIudBH9eXlXuUnj0g5IQ GlMXvR+R64Sv5h7lOxoe0VoWzI5azV2YQ2GtLHDwEpgD7OJ3RiM7Uj6LZgLxgxSHq+WY+ 4yBS9V4emyzVqwT0ceFBdchJErCCZ1N56Ajfw7GQpZ3ifowXR5jh0k8lVpd3Dsb7UaXrz xT74h4dQtu0gL7PCvPDR/EcAv6pP5vNXbqctu9iTrvqdXB7SFCMl77ejWU1zhKTvpLJQW prpzS8qzGLRVEkQJw7fkL21AVIya6ZL1F7nEhldi3baxJXuwv1cU+axuNQCpCyZMtpg== ARC-Message-Signature: i=1; d=subspace.kernel.org; s=arc20261015; a=rsa-sha256; c=relaxed/relaxed; t=1793136312; h=DMARC-Filter:Received:DKIM-Signature:X-Google-DKIM-Signature: X-Forwarded-Encrypted:X-Gm-Message-State:X-Gm-Gg:X-Received:Received: From:To:Cc:Subject:Date:Message-ID:X-Mailer:In-Reply-To:References: MIME-Version:Content-Transfer-Encoding; bh=FF5WnnOMO3EPNW7Tu8nfwZQBRS3X57+RVAxmjEP9KT4=; b=CDZr2OPdNrfvK733gowfXXTXOSo+PDrnu2ErVzQvddvXI0kDsS0mYy7dtblVoJM/gcBw E+j+tyrByqYJQcjZRuYesZOWoIgMDM3nEzfdqBtdZ2/N3NzaPxutKgmxdLN3JLv/nSuSW FW4A6oxyY60GKHcPGSL99BBoyXVNXSTuBz5wmdyikaL/95DUeNNnlnez2W5yHIcIM7jqV MS+gXO91O9VC6W1j7TJ8cwjtnZKd12woIMtyqQFJEoiphfl9AyGAJa6pLNEXXRLUhmJPB 1za9lYUGi/+rLzB/IgPa8poyJhxervnMzOevZ0l/n7G6SQAu+lc/GmRjWCd0iwbL4Gg== ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass header.from=gmail.com; spf=pass smtp.mailfrom=gmail.com; dkim=pass header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20260707 header.b=jDgMYkdC; arc=none smtp.remote-ip=209.85.208.53 Received: from mail-ed1-f53.google.com (mail-ed1-f53.google.com [209.85.208.53]) (using TLSv1.3 with cipher TLS_AES_128_GCM_SHA256 (128/128 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 16B4E606A31E for ; Tue, 27 Oct 2026 21:25:11 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.2 smtp.subspace.kernel.org 16B4E606A31E Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=gmail.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=gmail.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20260707 header.b=jDgMYkdC Received: by mail-ed1-f53.google.com with SMTP id 4fb4d7f45d1cf-6b408f2d936so575949a12.1 for ; Tue, 27 Oct 2026 14:25:11 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20260707; t=1793136310; x=1793741110; darn=vger.kernel.org; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to:content-type; bh=FF5WnnOMO3EPNW7Tu8nfwZQBRS3X57+RVAxmjEP9KT4=; b=jDgMYkdCZ0/aX/InBd/FYxPslr+3Q4rInRUJRjGR8BMFCa4dmOhpdLhhxJr1bohyat NlnazmJYNdbc0RPHgqjdNeUhUiGrRHZPk44EqqzfHcc/M6uMaON8CnemrF8M+ZiTDewZ xNvG9+1kYjA99CINrHh3/3NyTxENQ9nYmaZBZF9BiKdll/h2eIQJiceeGtSl+ogjQNZ5 /M08jVEfHN72r1mWPRx9ZpJNv2zwPpCho/ui4MAu4/of/UtWmKYndjWH68F9jtsPmZSY 3OCj2YPRvV0BPYYtnTDTZnYDL8DEWw9K+SJBhjSWrXP7dkdp7anmqST6R8lHi8f5KXWX 2UGQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1793136310; x=1793741110; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-gg:x-gm-message-state:from :to:cc:subject:date:message-id:reply-to:content-type; bh=FF5WnnOMO3EPNW7Tu8nfwZQBRS3X57+RVAxmjEP9KT4=; b=i0QgCuFN3ocmzOWjGj0FiwRcdrq5/lVIEI1e2DFL9huKxdg44zi4pO6NLFNAVvnm4G hDbQ8t67I1u5Y5SwEqTaHB/iIJActx8hhrkvxmxeQcaNb6yuAndful5Har2mamW8to/h +ApAuHGFbL2hwHfGFju0ayDUH8jrkLWQd+i98j+gxZB3nDCu5zE644sGdIU+sJi0X8B6 pjUXCx6sJF91gKv1hUiqJgevza5jVvXRLtOzBw9u7nP2CLiPMFkm7r2JdvJ+SFUYiNpH vxuScvHo6dwKBmq7/XO5q4T3FjhM7UHt86u3YMQ2TSjiP4KymTeArR1tnFLnd4ujiT8C MfYA== X-Forwarded-Encrypted: i=1; AKwUvBwb3Z4QYxOdINr2+gJzRkONjkAcYJ+YeY8D9txp/d4gCvlsj+F9A8ftQmXC24ISqO3CXHsH8E0kY8QgnYw=@vger.kernel.org X-Gm-Message-State: AFq9FYKKDDUHnLtuXq33654/1tjpsdwQCjN4BiGb3dTRDvOQQpA2uq/H /iEqLlzf2Onebu3KLpsmpHx45L0v2yu20BlpAqfx5dEDchZ6HL9n6r1a X-Gm-Gg: AYBFou0ut/P7pqJVd4Cf+vkKorIHCtN7gbLHUxPc72i+nxTQkqun5IrbYJ9An5khGT1 EKmLFRNJvUwtsPqGAwptcUYSVnN0VmJVNwYRmM73a+IVZAGhRnQpqfmaI/RKs881ko6bSt2MTYL nbmhZE8DvbHM0Vqc5dDy65jmu8zOX2mscVD/Mq0cLAWcg20N9kL3YiABycxz0oQQZW46t18iy8I un1ZL/+11xr7fpJo9wop2Yfi/6pEHGWFZC3KMEKktjfsu+jiryk12YfB5uMyRnX2lAqU+HWS7me Y/yijaMFDPB0kY86G2ltdXKS3pLlAsT/wbL6MsJqPVNrkBlqFtRHGfG6WTdVSkuI7u/V7t0PyI3 JjsIUzQWE5fHsHPZinWbXv9AeO2wC0gIJuJUyidPy/Z1KO+jzd3yEIGQ8SZgRsMHmNrhvUgBxVx 5l8SQHZG/O/viV7L2z/464y4eOCTIvBUC50d1WVZENKFBAftgcX0700GvGQFwir8vZmld0s9DPU YqSfR4LghBTiK7XH3pHovZbO0B/T6ElHIhN/ytmyyr3l99pLG4n8tYF/k+Lzk46D1Fj5BvwexNW twbC9cYn3wywV8QmzD0KWZg3P1Mbqbmuz7TpY1KgTMJ68Uy/hwt/fsL5f6iM X-Received: by 2002:a17:907:94c2:b0:c40:eb1a:4c8b with SMTP id a640c23a62f3a-c49bdf77980mr40681866b.29.1793136310349; Tue, 27 Oct 2026 14:25:10 -0700 (PDT) Received: from CCM-PC (83-233-221-133.cust.bredband2.com. [83.233.221.133]) by smtp.gmail.com with ESMTPSA id a640c23a62f3a-c46bd350b52sm513224766b.7.2026.10.27.14.25.09 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 27 Oct 2026 14:25:09 -0700 (PDT) From: Yongzhao Chen To: Andrew Lunn Cc: netdev-bot+sinfo@kernel.org, netdev@vger.kernel.org, Christian Marangi , Vladimir Oltean , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , Simon Horman , Russell King , Florian Fainelli , linux-kernel@vger.kernel.org, Ziyang Huang , Stanislaw Pal Subject: Re: [PATCH net v7] net: dsa: qca8k: preserve port state across MTU changes Date: Tue, 27 Oct 2026 22:25:05 +0100 Message-ID: <20261027212505.1848-1-yongzhao.derek@gmail.com> X-Mailer: git-send-email 2.55.0.windows.5 In-Reply-To: <47e9713f-815e-4caf-8928-a7ec12d0087b@lunn.ch> References: <20261022155837.760-1-yongzhao.derek@gmail.com> <179268501671.3290.6623232109527554630@kernel.org> <20261027092718.266370-1-yongzhao.derek@gmail.com> <47e9713f-815e-4caf-8928-a7ec12d0087b@lunn.ch> X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Hi Andrew, On Tue, Oct 27, 2026 at 01:54:16PM +0100, Andrew Lunn wrote: > Is this a real problem which bothers somebody? If it has not been seen > in production, it sounds like it does not bother anybody. So net-next. It has not been seen in production. Following your suggestion, I will move it to net-next. v7 needs another revision anyway. Sashiko's review [1] is right: a concurrent PORT_STATUS reader such as the PCS poll can corrupt the MTU snapshot, because the qca8k regmap is created with disable_locking and shares its work_buf. Clearing the MAC bits unconditionally would not be enough, since the restore uses the same snapshot and the MAX_FRAME_SIZE write also goes through work_buf. Stanislaw's patch [2] enables the regmap lock. With it, the v7 code passes a local KUnit test that forces this interleaving against the real regmap core. I will send v8 for net-next once it reopens and [2] is in net-next, and say in the commit message how the problem was found, as sinfo asked. [1] https://lore.kernel.org/netdev/179303171241.3134.15019965307136674652@kernel.org/ [2] https://lore.kernel.org/netdev/20261022192933.384898-2-kuncy7@gmail.com/ pw-bot: cr