From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature ECDSA (prime256v1) server-digest SHA256) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id A9F91606A319 for ; Thu, 22 Oct 2026 22:29:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key, unprotected) header.d=lists.infradead.org header.i=@lists.infradead.org header.a=rsa-sha256 header.s=bombadil.20210309 header.b=SV0nW+Y5; dkim=pass (2048-bit key, unprotected) header.d=gmail.com header.i=@gmail.com header.a=rsa-sha256 header.s=20251104 header.b=d2TyUmbn DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20210309; h=Sender:List-Subscribe:List-Help :List-Post:List-Archive:List-Unsubscribe:List-Id:Content-Transfer-Encoding: MIME-Version:References:In-Reply-To:Message-ID:Date:Subject:Cc:To:From: Reply-To:Content-Type:Content-ID:Content-Description:Resent-Date:Resent-From: Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Unsubscribe-Post: List-Owner; bh=S9nvo0dYAQsPs8WnHZoy9/22ZqY9nCZeAyTVnl3n0P0=; b=SV0nW+Y5JasmRI RB2/5wGd3jRWFPnXS2bUMMOqbGYmWRLwSu/CK4tCgOOjNZZ+KBnvCkRNF8ccuS+/rkkJzOtOVMrHt sksa/2pFlcE51ttegh8rdY37z4INRAhQAsgY4xHm9Nm2gHK91K3YcuvcX6U1augbJoro1NRF8Fpv6 WemCIKEUhP6Nwscfy+JWGi6vf9DNfOaqP8dGuO7/kXobgHenn+kXeDluoXvosm2G6EzCVkjqhu2NC LiVe2WRSs3T9Gvv0GXLGhLP14q9k1zGj45pmb+lNpd6wtNFkwJsAhT6x8nfcgu5xKpBUv8GvHHiXd dRpM4EzEvlrckBRItfxA==; Received: from localhost ([::1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.100.1 #2 (Red Hat Linux)) id 1xK1H7-0000000F4s8-11Uh; Thu, 22 Oct 2026 22:28:41 +0000 Received: from mail-vs1-xe2f.google.com ([2607:f8b0:4864:20::e2f]) by bombadil.infradead.org with esmtps (Exim 4.100.1 #2 (Red Hat Linux)) id 1xK1H5-0000000F4rf-1Cpm for linux-arm-kernel@lists.infradead.org; Thu, 22 Oct 2026 22:28:40 +0000 Received: by mail-vs1-xe2f.google.com with SMTP id ada2fe7eead31-7cc2bb73cd9so118771137.3 for ; Thu, 22 Oct 2026 15:28:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20251104; t=1792708118; x=1793312918; darn=lists.infradead.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=S9nvo0dYAQsPs8WnHZoy9/22ZqY9nCZeAyTVnl3n0P0=; b=d2TyUmbnHXe629H+LL1fXsdwIr6oKfCVEQhxn55LPlP5It245GwWWD3p7e46CvKlpn JpIp213spfLsP/1I1YPW2JNVNA406NjrQ0MjaSdH0w2+3IqtY3mm65OPZyOkH4eQRnl0 sZ7F8qcoyyVlVhOgyy8/HQmHg9C6l4I30OH/Q03pGz/xEtNz356PZCfWMPhzDfibIYnk pVVq409CcHt/s1zd4p8OX5DrL3q6POiX1/QSfi3dMJiVwIIOUoqACtmp1ZaXX2KKxcho LrxBDRnDL3ufnZadvhpif4uyzpEQ/R1Y58HCiQqh+xX+Ye018gnzlj5eVBrzfNxiWn90 tb/g== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20260707; t=1792708118; x=1793312918; 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=S9nvo0dYAQsPs8WnHZoy9/22ZqY9nCZeAyTVnl3n0P0=; b=rPr8qqdvwDIO+ObsCkbV9Ts4IQLhHzdBHTL+L8P3i6wchAIjF0pguKoaAJ/XmhFLfF plpj5f97dDJm3Hkn4q7U3ew5hfKf+mqcJCam49yUNsEKZNNAavPJpF44TWkAf4MttsaK D3WDTTxnkrrVYc/uL/3NI0M9ZNw+/azjecMCaWWP+dP9Ou3cSwXUvxiUtVwgVBJmhg+P 5fg5Z1eZxAnBfhw5gw9NiYdzqfr2fuu9rTr8SpJGtCZQ0XO99IM56Sl4YEyK5TJLjPRR fRHm/9jSjXC5g/du0P23DyOcHRkg3IZ5lQXIL1mAorp3ap+VvYzeedelqKxzSzy4U2Sj kuCg== X-Forwarded-Encrypted: i=1; AKwUvBzNVXWTie2700Om3+85V8e6qwrf8R6nfNEyrsotRt03mr9lT6iGz2VjwQmNuPXVzJNgtXhs9l462ADQKgm8lAyd@lists.infradead.org X-Gm-Message-State: AFq9FYKJ+RxSdreLGyjBWOFPnsHfMFuU/m1/JZjsSkbWBXcraYQRHkBS ld2DD/lWBYkS5BjZTbHihO5Sv30k0InSggQrBRhF1uNH7ycvOUTT/qNZaMoxV5fG X-Gm-Gg: AYBFou1ZhpnQLpTiXpHwFMDt1ibiYG0mTYhAFpTBPBvqbMFyagfQl7pxq8uhuY8qcW+ P7ydopIz15nCOR1LRMLaC6As3k+OPkQ+FRMH2K9NCYT9Sunmzg8LIFo2cH6xXFUHOJvVyEzjU1n n8kxBzsbSP7W12YcUNxxAAmJJ0PwAgOo7RA536ONHxF2qB/WiiknAnSpD4i+nbm6sNLfk2Wi6DC yEI15kBPtCYzGVT724quG+z34qhJAGftrc69+bdDkFW8mrHeRLKV+IZyvtvIC7d+VAp75G5eXqe f2T8+lefwN1kyCwIQnPsTjZGz1Db/kaHnWPM4SPcH+a/eoRHYuqeMmoZw4XWXs3FzrADiI40BHP FuV/zjoZkvdWWk08+5fiLJp12qfEcfJgcjMxukhPXm+9UHc+xo8eM/5QqYiGcr2Qx5IxBeH/Fra 5mMjRnjmJiG6XAd3e149gQT0kCqHRqMP3y0716jnygkErUtzqn6KSICG99vjv1PY6zw98wna3MJ BKrhenhNoLc5L5guQETr8bi0UhG+ntXxcuk1W62BljEO7YcGkSgly4vGs6u+/gaVoy+kRH8rU6p QLsGWDrYxAV9JXwMfMOG X-Received: by 2002:a05:6102:290e:b0:7c3:1213:1e2b with SMTP id ada2fe7eead31-7ccc337cf94mr314700137.18.1792708117775; Thu, 22 Oct 2026 15:28:37 -0700 (PDT) Received: from Biostar-A520MT ([187.94.15.233]) by smtp.gmail.com with ESMTPSA id 71dfb90a1353d-5ec13f2cfe0sm481582e0c.14.2026.10.22.15.28.34 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 22 Oct 2026 15:28:37 -0700 (PDT) From: Breno Rodrigues Alves To: Jonathan Corbet Cc: linux@armlinux.org.uk, Bart Van Assche , James.Bottomley@HansenPartnership.com, mkp@kernel.org, linux-arm-kernel@lists.infradead.org, linux-scsi@vger.kernel.org, linux-kernel@vger.kernel.org, Breno Rodrigues Alves Subject: Re: [PATCH v4] scsi: arm: Convert acornscsi-io.S to C Date: Thu, 22 Oct 2026 19:28:19 -0300 Message-ID: <20261022222819.92507-1-breno3011alves@gmail.com> X-Mailer: git-send-email 2.56.0 In-Reply-To: <87wlr9z8iq.fsf@trenco.lwn.net> References: <20261022183658.58090-1-breno3011alves@gmail.com> <20261022185224.60700-1-breno3011alves@gmail.com> <20261022185224.60700-2-breno3011alves@gmail.com> <871p9h1kc7.fsf@trenco.lwn.net> <87wlr9z8iq.fsf@trenco.lwn.net> X-Archived-By: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.9.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20261022_152839_387642_7630BA42 X-CRM114-Status: GOOD ( 16.22 ) X-Spam-Score: 1.2 (+) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Archive: List-Post: List-Help: List-Subscribe: , Sender: "linux-arm-kernel" X-Spam-Status: No, score=-10.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,DKIM_VALID_EF,FREEMAIL_FORGED_FROMDOMAIN, FREEMAIL_FROM,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham autolearn_force=no version=4.0.1 X-Spam-Checker-Version: SpamAssassin 4.0.1 (2024-03-26) on aws-us-west-2-korg-listserv-alma10-1 Hi Jonathan, You are right, and I should have been clearer about the motivation. The reason this patch exists is that the original assembly has a latent bug: for odd transfer lengths, it drops the final byte. The C version fixes that, and the odd-length case is now exercised by the userspace unit test. But that bug cannot be triggered by any current caller, so even the bug-fix justification is weak - it is a fix for a path that nothing currently exercises, in a driver for hardware almost nobody still has. You are also right about the broader point: "assembly to C" on its own is not a justification. The kernel's assembly is there for reasons, and translating it for its own sake is churn that reviewers have to pay for. I have been approaching this as a translation exercise, and that is not the right frame. I will not propose further conversions of that kind without a concrete functional benefit - something that fixes a bug that can actually be hit, or enables a change that cannot be done in assembly. Bart's Reviewed-by: stands on the technical merits of the change as a change (the C code is equivalent to the assembly for even lengths and correct for odd ones). Your concern is a different question - whether the change should exist at all. Both are valid, and the decision belongs to the SCSI maintainers, not to me. If the consensus is that this patch is not worth the churn, I am happy to withdraw it. I would rather withdraw it than have it sit in the tree as an example of exactly the kind of change you are warning against. Thanks for the direct feedback - it is a useful correction to how I was approaching this, and more valuable than the patch itself. Breno