From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 0A6C8145B3E; Sat, 6 Sep 2025 01:56:09 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757123770; cv=none; b=E3dAFNUkxfcw5doAozZ5/bl/if8X5/HqcAARsHiyz108ysgAGoJUra1Q/RbXEXPgE9LEDJTaXJsXEwQM437Y7M6K9K/flferhyxeXbxOVNzvWb/7MCoHpPIIpgfTPvVKHQSHPtoju8okLkcSUzsfRZmlSsH6Zrz8sIaRtdUYaYw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1757123770; c=relaxed/simple; bh=2N5oPQH0GrIyzi7ps5mcWTPe4nuxHMMFUsSOQvXSTTc=; h=Date:From:To:Cc:Subject:Message-ID:In-Reply-To:References: MIME-Version:Content-Type; b=tYSNglJzvqMr8i+LYQSrqAlg98KBPitvmgxbcTzfcKzj9HiZIIfo3CMls1UWAQXSY4D8kFB7HyNkd+MO/VozfdI4R2uy+cLbj5GEDFG+JhP4ywj8Sv1Lk9LlC1cixrIe2rBUoEZbXwV/v1vsK+TNj22Cv2fDvxst143MISqxunk= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=AqEVm47n; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="AqEVm47n" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 0F508C4CEF1; Sat, 6 Sep 2025 01:56:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1757123769; bh=2N5oPQH0GrIyzi7ps5mcWTPe4nuxHMMFUsSOQvXSTTc=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=AqEVm47ncbNtowEtefsD+kBgd3Mwx+H8P1sdRy/JlE9lRIYzGJaRTSq4zibX9KHwI PEtjOv3Nht0n4em8lhT4914UH5ZGds2YhHwxq7DRhd6cQfWfeRLbVg97tDO1xryJFG HKpLWd8dsrO5fqiGGd932WSvp/jGrVCoV3oDJC1AE8hbs8UFc3cSH+MxNCIVdlu8Mq JDHvvuQZTEHCUuTzwfJPqAdM14+QvSzEqPPwHa5DjsiPvgoMmp2lz/A1UAzfavGOMc VfjSbT2geNZeXkvwmsve66KVSYLxesrVFuvrrrFSIIf+wOwfnFVgeKW/1MmevCdEWZ gK44hQxqXKCmA== Date: Fri, 5 Sep 2025 18:56:06 -0700 From: Jakub Kicinski To: Shenwei Wang Cc: Wei Fang , Andrew Lunn , "David S. Miller" , Eric Dumazet , Paolo Abeni , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , Clark Wang , Stanislav Fomichev , imx@lists.linux.dev, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, linux-imx@nxp.com Subject: Re: [PATCH v5 net-next 4/5] net: fec: add change_mtu to support dynamic buffer allocation Message-ID: <20250905185606.42328008@kernel.org> In-Reply-To: <20250904203502.403058-5-shenwei.wang@nxp.com> References: <20250904203502.403058-1-shenwei.wang@nxp.com> <20250904203502.403058-5-shenwei.wang@nxp.com> Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Thu, 4 Sep 2025 15:35:01 -0500 Shenwei Wang wrote: > + if (fec_enet_alloc_buffers(ndev) < 0) { > + fep->pagepool_order = old_order; > + fep->rx_frame_size = old_size; > + WRITE_ONCE(ndev->mtu, old_mtu); > + fec_enet_alloc_buffers(ndev); And how do you know that it will succeed now? You can't leave the device in-operational due to reconfig request when system is under memory pressure. You need to save the previous buffers so that you can restore them without having to allocate. > + ret = -ENOMEM; > + }