From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id C5641C433EF for ; Fri, 13 May 2022 17:04:29 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1382723AbiEMRE1 (ORCPT ); Fri, 13 May 2022 13:04:27 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52208 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1356197AbiEMREZ (ORCPT ); Fri, 13 May 2022 13:04:25 -0400 Received: from dfw.source.kernel.org (dfw.source.kernel.org [139.178.84.217]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 66AA326D7 for ; Fri, 13 May 2022 10:04:24 -0700 (PDT) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by dfw.source.kernel.org (Postfix) with ESMTPS id 01D5861F82 for ; Fri, 13 May 2022 17:04:24 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id D3F6BC34115; Fri, 13 May 2022 17:04:22 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1652461463; bh=GJ6CMMnqTxjbB9oNTRvQbgOX+aFkYzqkYpmRMH1CL0A=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=SdBPU/wi7nRq/KrwlU5VXIDOhv55OaNN/Vib3ZDv/k4ckFFuzLD5s93VqqBVfQUhm I+4//wAPQm2mN1MVlfnjU7M7s0GlsmV09SdkjweBuFeDFMt0sLYNlbvuJK1FJcEUnA iAP7tl2DcxWoAFeRaBTahBrNfC5VO1qybduJoMr9YUcA5L1RsiloyabUA9P6ZqafVB ovXstYxEcT4zXvUuFEr4yAzj26EAMkCQEAzJyLa95ISsCR2OqHb16II7zIcSW4qF4e s/iTLDZm1IVAQPb4R1h3KYChyK7EX0cEm9dJJN54sblU9F8mZNl0SdaaLMxZl4SLmE C6k9QRJLxvvmw== Date: Fri, 13 May 2022 10:04:21 -0700 From: Jakub Kicinski To: Eric Dumazet Cc: Saeed Mahameed , Paolo Abeni , Eric Dumazet , "David S . Miller" , netdev , Alexander Duyck , Coco Li , Tariq Toukan , Leon Romanovsky Subject: Re: [PATCH v6 net-next 13/13] mlx5: support BIG TCP packets Message-ID: <20220513100421.7c6d9f20@kernel.org> In-Reply-To: References: <20220510033219.2639364-1-eric.dumazet@gmail.com> <20220510033219.2639364-14-eric.dumazet@gmail.com> <20220512084023.tgjcecnu6vfuh7ry@LT-SAEEDM-5760.attlocal.net> <51bc118ff452c42fef489818422f278ab79e6dd4.camel@redhat.com> <20220513042955.rnid4776hwp556vr@fedora> <20220513054945.6zpaegnsgtued4up@fedora> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, 13 May 2022 06:05:36 -0700 Eric Dumazet wrote: > The problem is that skb_cow_head() can fail. > > Really we have thought about this already. > > A common helper for drivers is mostly unusable, you would have to > pre-allocate a per TX-ring slot to store the headers. > We would end up with adding complexity at queue creation/dismantle. > > We could do that later, because some NICs do not inline the headers in > TX descriptor, but instead request > one mapped buffer for the headers part only. > > BTW, I know Tariq already reviewed, the issue at hand is about > CONFIG_FORTIFY which is blocking us. > > This is why I was considering not submitting mlx5 change until Kees > Cook and others come up with a solution. We do have the solution, no? commit 43213daed6d6 ("fortify: Provide a memcpy trap door for sharp corners")