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 70AC547125C; Tue, 21 Jul 2026 17:54:45 +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=1784656486; cv=none; b=gnY+QsubEJ3P8u/YQ9/pWtOeRvbrhcUKM2owbAAoqrJv0XFRPcwuihJzG5oJJu1FKF7ASMs+T29UQGCZsPQPaM9XvcNFcP3T+K/VBo5PaiLn9vKIJFXss/+EAuLFY3ejsuF8ATFIMWVIXezifIDSdTSzmvUOvBz407cjmTp8b9Y= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784656486; c=relaxed/simple; bh=VsxgSGHIrDjbE4z1Sir+dX926ky0ASw5FqMugOzTT5A=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=sd8glue5RQ6TojGzZPBV7Q06FziVGpD9KolCQSaH4zThZT80fjWzVERFhKMVQ36EtdmuU55QfaL2UuvxD0dYMoruZqlWcgyNlP2LYvQ1TpvyL+43SAx68zhbCq6klmZDEAPceAmJeagMRz8W0o3w7TLW+cm3qlG584oPRWWNeQU= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=KHHSuEjy; 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="KHHSuEjy" Received: by smtp.kernel.org (Postfix) with ESMTPSA id F12681F00A3D; Tue, 21 Jul 2026 17:54:44 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784656485; bh=cdP/RUX80kzT4MryGo4eUHqqhbly8a3X34uVQU5OmdE=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=KHHSuEjyRVHFpSVK59IrixK7ERPxw9Bp9FEp3E+30yShjdMJfw2BD6t+Tbv7FOExB uicg79tG5EmBW4JZIQJnBIJPFdwEgdJaKvavgdW59fsC3EzwBdodJncaRPSNN/JV8Y +DlypmhGOR9ln76bKMwx5iLjoK1gbOE/f00PhE5kYkzTcHinKi5m8subR8UgidmWSI J2N88yyw0ILE+KkWndCk9YNGj2k8K1Jqr1bq938KND1C9EzEA3Y1DeYc5+CBkKPDKV jhHwTsa4fJVN9/s8HKkiVYBKKXzOMLOoxH09WT4KcVylTWeDBn2LZXr4ijabwpyAst 9nktvmY/Dv9OA== From: sashiko-bot@kernel.org Subject: Re: [PATCH v3 4/8] md/raid1: don't use write-behind for P2PDMA bios Reply-To: sashiko-reviews@lists.linux.dev To: "Mykola Marzhan" Cc: yukuai@fygo.io, linux-raid@vger.kernel.org, linux-pci@vger.kernel.org In-Reply-To: <20260721174502.111503-5-mykola@meshstor.io> References: <20260721174502.111503-1-mykola@meshstor.io> <20260721174502.111503-5-mykola@meshstor.io> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Tue, 21 Jul 2026 17:54:44 +0000 Message-Id: <20260721175444.F12681F00A3D@smtp.kernel.org> Precedence: bulk X-Mailing-List: linux-raid@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: > alloc_behind_master_bio() copies the bio's data with bio_copy_data(), > a CPU copy. P2PDMA pages are peer device (BAR) memory; generic code > must not assume CPU load/store access to them is safe or fast on > every architecture, and bouncing peer memory through the CPU defeats > the point of a peer-to-peer transfer. >=20 > Skip write-behind for P2PDMA bios: they are written directly to all > members, including write-mostly ones. Ordering against write-behind > I/O in flight to overlapping sectors is preserved: the non-behind > clone path serializes on CollisionCheck rdevs (see the preceding > fix), which covers these bios like any other write that bypasses > write-behind. >=20 > Fixes: 02666132403a ("md: propagate BLK_FEAT_PCI_P2PDMA from member devic= es to RAID device") > Assisted-by: Claude:claude-opus-4-8 > Signed-off-by: Mykola Marzhan Sashiko has reviewed this patch and found no issues. It looks great! --=20 Sashiko AI review =C2=B7 https://sashiko.dev/#/patchset/20260721174502.1115= 03-1-mykola@meshstor.io?part=3D4