From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on dcvr.yhbt.net X-Spam-Level: X-Spam-ASN: AS3215 2.6.0.0/16 X-Spam-Status: No, score=-3.9 required=3.0 tests=AWL,BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI,SPF_HELO_NONE,SPF_PASS shortcircuit=no autolearn=ham autolearn_force=no version=3.4.2 Received: from out1.vger.email (out1.vger.email [IPv6:2620:137:e000::1:20]) by dcvr.yhbt.net (Postfix) with ESMTP id AAE5B1F51E for ; Mon, 26 Sep 2022 18:09:42 +0000 (UTC) Authentication-Results: dcvr.yhbt.net; dkim=pass (1024-bit key; unprotected) header.d=pobox.com header.i=@pobox.com header.b="hxgmcE/2"; dkim-atps=neutral Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231329AbiIZSJY (ORCPT ); Mon, 26 Sep 2022 14:09:24 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39444 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231349AbiIZSJH (ORCPT ); Mon, 26 Sep 2022 14:09:07 -0400 Received: from pb-smtp21.pobox.com (pb-smtp21.pobox.com [173.228.157.53]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 611931EEC1 for ; Mon, 26 Sep 2022 10:55:05 -0700 (PDT) Received: from pb-smtp21.pobox.com (unknown [127.0.0.1]) by pb-smtp21.pobox.com (Postfix) with ESMTP id 5F7091C60BB; Mon, 26 Sep 2022 13:55:05 -0400 (EDT) (envelope-from junio@pobox.com) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed; d=pobox.com; h=from:to:cc :subject:references:date:in-reply-to:message-id:mime-version :content-type; s=sasl; bh=ZBHUzf+1hk+hsD0il+ajufCxkqw7iTk0+hRINJ gl4BU=; b=hxgmcE/2hQJRnXmD+PoMMdBfkz9lFbapEQk7cu7pTo21s7shyaNUyF njWQbAupNHcXCYH6t9/7JXqrPWGUZixqyRSxS8xE9qRogSe55ISz24aqzrSE9jCI S2QrH7+RAi8PknFTNvnp18lTJOYT2fgGJrjOzqNOtgBSuJHrVCByM= Received: from pb-smtp21.sea.icgroup.com (unknown [127.0.0.1]) by pb-smtp21.pobox.com (Postfix) with ESMTP id 58ACF1C60BA; Mon, 26 Sep 2022 13:55:05 -0400 (EDT) (envelope-from junio@pobox.com) Received: from pobox.com (unknown [34.83.5.33]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by pb-smtp21.pobox.com (Postfix) with ESMTPSA id D573C1C60B6; Mon, 26 Sep 2022 13:55:00 -0400 (EDT) (envelope-from junio@pobox.com) From: Junio C Hamano To: Phillip Wood Cc: Victoria Dye via GitGitGadget , git@vger.kernel.org, peff@peff.net, derrickstolee@github.com, Victoria Dye Subject: Re: [PATCH] read-cache: avoid misaligned reads in index v4 References: Date: Mon, 26 Sep 2022 10:54:59 -0700 In-Reply-To: (Phillip Wood's message of "Sun, 25 Sep 2022 09:25:08 +0100") Message-ID: User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-Pobox-Relay-ID: 577AC34C-3DC4-11ED-A105-B31D44D1D7AA-77302942!pb-smtp21.pobox.com Precedence: bulk List-ID: X-Mailing-List: git@vger.kernel.org Phillip Wood writes: > I was confused as to why this was safe as it means we're still reading > the individual fields from unaligned addresses. The reason it is safe > is that we use get_bexx() to read the fields and those functions > handle unaligned access. I wonder if it is worth adding a note to > clarify that if you re-roll. I've got so used to ours that gives unaligned accesses, but I guess in some other circles, get_XeYY() means reading YY bit-wide integer in X byte-order from a preperly aligned address, and if that is the case, I do not mind such a comment somewhere. It would help those coming from such a background very much. Thanks.