From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-alma10-1.taild15c8.ts.net [100.103.45.18]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 88110415B8D; Tue, 13 Oct 2026 22:10:13 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=100.103.45.18 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791929414; cv=none; b=NzKs5IAKll3y+YxgvlGhi/0ij5DA0qhqCUBbewb5HhRpCiSLoeiKftI3BPOqor/Atxz00K4q3PAuhuYrjlWrfcthCn6nFt2PO/epRsBpCAq2qlBSkxUeIlhDkdR2bYPNLLbmYd2Nvhvfcd6Fen5ckoz1Ff4ruW4LCDNvIJcIcRw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1791929414; c=relaxed/simple; bh=RWkMtynZxJyaD0r8fxVdAZVpWqTNJMgs9eWfNAjx01g=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=Wkg1WAT4qQjDS0U1ehzLj7Vcn2B3BFtUElPFl5/n78kJYoIfsvwf1PfESu7lCeJzsfWGhoiZQ3Ty2nj4WyOfJJFlRFqE4OM4FuHag62hVGW+3EQit7qK2wzrm5k+nxwoBRNtRae4fCxidhixtWUeTGVNmO63owE/hOK7/IC/IaQ= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=g+Eshj8V; arc=none smtp.client-ip=100.103.45.18 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="g+Eshj8V" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 4E2021F000FF; Tue, 13 Oct 2026 22:10:12 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1791929413; bh=X/RsM2Ek4zZ53axGZAyenVk3blcnKjokWtjpwX3I6+4=; h=Date:From:To:Cc:Subject:References:In-Reply-To; b=g+Eshj8VmAVzH92w4Bde1RZficE6gJJiXdbIjKKHVQBMbvb6AhSkuF99HJqelj7Jj ysZsDmS6VEpxBbMOdpIzmX/9s1d1wMzAx8/cXbN6NJ//1BYi0im1JEzFQC3MaARO0y brefhnDDFg9axFJxKAxO79ToTq8/5YDxD/1fqLz4CWCtfuajDANkytXUD4lO+krD8I EP0TCDYZmXd7R6m9TFCI4aDhzuqdUJx5qgeBVZt+ysPkRHIi28n7U4/k86KlqUFXA5 KEJNM6Jval3shB0Nqx9FWmVhgQITxGkZZ5Tm+hX0uLlUdBzLHSWYK7x6zT+gBizj1y haIxi3dKB1c/g== Date: Tue, 13 Oct 2026 23:10:09 +0100 From: Mark Brown To: Jisheng Zhang Cc: linux-spi@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] spi: dw: Fix missing smp_mb() in dw_spi_exec_mem_op Message-ID: References: <20261010151529.30590-1-jszhang@kernel.org> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: multipart/signed; micalg=pgp-sha512; protocol="application/pgp-signature"; boundary="y+zpgi+VOfE/ZT/n" Content-Disposition: inline In-Reply-To: <20261010151529.30590-1-jszhang@kernel.org> X-Cookie: Some equipment shown is optional. --y+zpgi+VOfE/ZT/n Content-Type: text/plain; charset=us-ascii Content-Disposition: inline On Sat, Oct 10, 2026 at 11:15:29PM +0800, Jisheng Zhang wrote: > Similar as commit bfda044533b2 ("spi: dw: use "smp_mb()" to avoid > sending spi data error"), we also need the smp_mb() in > dw_spi_exec_mem_op() after setting up the members in "dws" to ensure > the data change is visible for all CPUs. Which other CPUs are we worried about here? Unlike the regular SPI path which can use DMA and interrupts for the exec_op() stuff we only do PIO and have interrupts masked during the actual transfer. If the task migrates I'd expect that to have all the required barriers, but otherwise it all looks single threaded. --y+zpgi+VOfE/ZT/n Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQEzBAABCgAdFiEEreZoqmdXGLWf4p/qJNaLcl1Uh9AFAmrOrEEACgkQJNaLcl1U h9ByHwf+JseUXHmXgzdaK2j+8Yl/r0QRuDG55IsoNcnWoOO0hv53nvA63UrGvLHX OIWcvyFlW6uIfCEwJd88ssBqoT38X/ARabke1EFjjVOFf9zefKPibMf3yGHKruWW 45HrEU+NTaTDObYNIxGZ6ec0hRew98YjmZHrkg8LzExEi5U8qxSvV7cS1q03maY7 Aj9Hp+pIhTpTY8RO1rsjlK/ljCKF6T0qIwBqDCkdoeOU5DfKs+BFEuHFhy5jyVSp be3RMfWPxk0CD9X9KCDSFB/EXli9K0qThwuidcT6uZC/k+hwZv/2LVxd4ij8eyOy cELOQ5KIAIf9JvrT4Cn0kTsrGcpg2Q== =aGTZ -----END PGP SIGNATURE----- --y+zpgi+VOfE/ZT/n--