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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-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Post: List-Help: List-Subscribe: List-Unsubscribe: List-Owner: Precedence: list MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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