From mboxrd@z Thu Jan 1 00:00:00 1970 Authentication-Results: passt.top; dmarc=pass (p=none dis=none) header.from=redhat.com Authentication-Results: passt.top; dkim=pass (1024-bit key; unprotected) header.d=redhat.com header.i=@redhat.com header.a=rsa-sha256 header.s=mimecast20190719 header.b=bbKpCfcx; dkim-atps=neutral Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.129.124]) by passt.top (Postfix) with ESMTPS id 1EE8A5A0272 for ; Wed, 29 Jan 2025 08:33:49 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1738136028; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=fn6Fe+b6jigxJGyEd/81HHe6TK28I6BsCUQ08+b10tY=; b=bbKpCfcxaFOTD+vSgFzfpAfOTYk6fJmc9/wckKc1V0HOfzKDWZSk8IyrCRS2+tnH4sBirP 21celrtXYUUFkVod7FcvnJ3Og114tOg57njuade5PLIDxy2b478tMpAgRHVCcmf6DPld87 7QplnFhY5XzC1NeQlEfAlSccRb7OZK8= Received: from mail-wm1-f69.google.com (mail-wm1-f69.google.com [209.85.128.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-135-P8r8SMW8MUayqLXONRMeyA-1; Wed, 29 Jan 2025 02:33:46 -0500 X-MC-Unique: P8r8SMW8MUayqLXONRMeyA-1 X-Mimecast-MFC-AGG-ID: P8r8SMW8MUayqLXONRMeyA Received: by mail-wm1-f69.google.com with SMTP id 5b1f17b1804b1-438d9f1faa0so6858465e9.1 for ; Tue, 28 Jan 2025 23:33:46 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20230601; t=1738136025; x=1738740825; h=content-transfer-encoding:mime-version:organization:references :in-reply-to:message-id:subject:cc:to:from:date:x-gm-message-state :from:to:cc:subject:date:message-id:reply-to; bh=fn6Fe+b6jigxJGyEd/81HHe6TK28I6BsCUQ08+b10tY=; b=o0yRR8BFv96X/s4ZQkMWj0juVIV3BNAeKW2jaay94Y/dcJfNxPtuZ/P8nY5W2i1n9Y u3aUlkr0vxEukkoYSa+HMPjqxuV1XyeMrl5TB4zTXQ1lL7TOJdhjhhfNhQ2FSwTfmjMj e3yIH2h20388DCoHbZLVaO8EWvg/TGS2dLP1vt7o8L1WqVXizjC7IwdjPUJh0GWZ1RCq jOpFhGyFGCr2I8p+rSOvQJBJkXSj6OQaawf7QmnkM88BkbE+RNfIkLIepWgeZu9DiLrl hfNmN18UyyvqdTQflAVc4erfkG6ue5tB9btbn7ct0Yx3MOOe3mKWo1IUbmFb8Z9BS9Iu aCow== X-Gm-Message-State: AOJu0YwpZgj9qHGFNpsmZgVunLuJzQ/KgQUmXu1c3NPW0TdEoZLKct+m 6y41awM+pI47Cn4L/XYIXF/nuvz6RjvOzLXGLiuwrvzp5sNR0XAPfNZg9W9sps/ZTMLqBRGyVg+ vJl2ejiCBSoFse/gBmq+C+NPD3DayjFSFxudDyLwanZP5jqQNFw== X-Gm-Gg: ASbGncsdEeZaBSv3HOQ87yOQDtcJprCNc2LNnT4ySygWbnpWxYbUVYBaQm/RWus2aNk lN4nfRakXiLvc51WgaMg6UMRAsMYyV4Q9OKp/ynQIdXIP5npHUfJPrLPKms2I3IC6CbcFkgFR4L 5GXBAOHshR7OdOYm/HwZDXbbLcGjIct9kRgEddq3BtjPKLIY2kwn7dnAqi41OtWm2AFnnJgiNd/ m0s/xPB7R3OgI9QJOYrcZmUs8c3aa0j2NS5MbU+BIDlBawAWdW5BkgWUBnUStR1Oqii5MeLNwD0 1KISPk9+TOg2f+F73nI1A9XNa5MWkAbZmQ== X-Received: by 2002:a05:600c:3c98:b0:436:e751:e417 with SMTP id 5b1f17b1804b1-438dc3c398emr14414745e9.7.1738136025216; Tue, 28 Jan 2025 23:33:45 -0800 (PST) X-Google-Smtp-Source: AGHT+IHFGPP28q4RdpHgmwhmAnAf/CpmfoJfBJpkaeDuCF5oMxmvNG4Ie7kua/RBnkpE2KJFhDkauQ== X-Received: by 2002:a05:600c:3c98:b0:436:e751:e417 with SMTP id 5b1f17b1804b1-438dc3c398emr14414545e9.7.1738136024862; Tue, 28 Jan 2025 23:33:44 -0800 (PST) Received: from maya.myfinge.rs (ifcgrfdd.trafficplex.cloud. [176.103.220.4]) by smtp.gmail.com with ESMTPSA id ffacd0b85a97d-38c2a17630asm16154639f8f.6.2025.01.28.23.33.43 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Tue, 28 Jan 2025 23:33:44 -0800 (PST) Date: Wed, 29 Jan 2025 08:33:40 +0100 From: Stefano Brivio To: David Gibson Subject: Re: [PATCH 3/7] tcp_conn: Avoid 7-bit hole in struct tcp_splice_conn Message-ID: <20250129083340.38926745@elisabeth> In-Reply-To: References: <20250127231532.672363-1-sbrivio@redhat.com> <20250127231532.672363-4-sbrivio@redhat.com> <20250128074833.716e4a66@elisabeth> Organization: Red Hat X-Mailer: Claws Mail 4.2.0 (GTK 3.24.41; x86_64-pc-linux-gnu) MIME-Version: 1.0 X-Mimecast-Spam-Score: 0 X-Mimecast-MFC-PROC-ID: 65VSKHKFqGmZu6-UQlfzsEYZTp8Dfgyup7URF62LUCw_1738136025 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Message-ID-Hash: 4EK2RBL7XYW2IBZC2CJIOLE6C3QFPJSU X-Message-ID-Hash: 4EK2RBL7XYW2IBZC2CJIOLE6C3QFPJSU X-MailFrom: sbrivio@redhat.com X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation; nonmember-moderation; administrivia; implicit-dest; max-recipients; max-size; news-moderation; no-subject; digests; suspicious-header CC: passt-dev@passt.top, Laurent Vivier X-Mailman-Version: 3.3.8 Precedence: list List-Id: Development discussion and patches for passt Archived-At: Archived-At: List-Archive: List-Archive: List-Help: List-Owner: List-Post: List-Subscribe: List-Unsubscribe: On Wed, 29 Jan 2025 12:02:09 +1100 David Gibson wrote: > On Tue, Jan 28, 2025 at 07:48:33AM +0100, Stefano Brivio wrote: > > On Tue, 28 Jan 2025 11:53:09 +1100 > > David Gibson wrote: > > > > > On Tue, Jan 28, 2025 at 12:15:28AM +0100, Stefano Brivio wrote: > > > > Moving in_epoll out of the common flow data created a 7-bit hole in > > > > struct tcp_splice_conn: repack by shrinking @flags by one (otherwise > > > > unused) bit. > > > > > > Is this actually necessary for the migration stuff? Or just a cleanup > > > you spotted along the way? > > > > I thought it was helpful to keep the same size on 32-bit, but it looks > > like it's not actually needed. > > > > Let me drop it from this series as it's just noise and I'm trying to > > keep this slim. If we are all happy with it I can apply it. If not I'll > > forget about it. > > Eh, I don't care that much either way. > > Note, btw, that bit-field packing is another way source and > destination could potentially have mismatching data structures. IIUC > bit field packing is described by the ABI and doesn't necessarily > match the byte endianness. Right, that's actually the reason that brought me to this change: I was comparing stuff between x86_64 and armv6l. On the other hand, this part of the specific ABI is generally considered stable so I can rely on it. -- Stefano