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 E0CB73C872A; Thu, 23 Jul 2026 21:01:49 +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=1784840510; cv=none; b=A3F4S7XPIKwWdPVSmMIG5WTbhnj5SM196OWPaEtN3WYcTuTZmAqGykOF0Ynm7+WkYQTEBKgCVeT81OK9nI2boQTw9A3scce3dczDun3A57A1axic8ohEE3Q1zbgpIKWPyYXdcUkNA2hXyl0brrCblK/DVSzkiYMaUpDaMlG72CA= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784840510; c=relaxed/simple; bh=ol9dBFBibD9sT6WbimjnkYLhGQU+LM1km9eXoG8ImyY=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=MWX1O/KEezCPP7zqCf5sLf5U+HQrDt9yWFqSZSg3qdxcTE2oVooXKNUskL3DioqQKIDqDOyam/Gzv4YCRBZ/g7R2HahKTAU+Xayp4hUe3KMgSc0t6GrAVckpZFyA3YTctQsb70uaCYH7B2cBnErUSNYFY80//aSDsRcEz5W4s6I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=d8+fz/Hb; 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="d8+fz/Hb" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 583331F000E9; Thu, 23 Jul 2026 21:01:49 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1784840509; bh=XqWvKmVpTqNOqKtLvoCKaLR0PWTLFbCypxGBRKWTLS4=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=d8+fz/Hbpx0BYAPb9IeDrh+xLkx9ly8BrBysd0aJUuRP+O43w98rtEeYUvV1n+ci8 gQ9Z2fZksYTWokRrrTff0IT4AdD27POnAHrCkqO8zqHubG8m8dGR+fCfU9cN4jQax/ ALP2RoFwF6++9QV3DgR5wD431ua0xo1M5zaMqzRtBionrmUC81G5nEGYhkeKTmLWp1 MCpHhKAButCm1gmTV6xNthT+VANNTP9PZeXJYUkSs3vfD3Y4dV6nnuLFN1rppGNfdJ HjggWKMN7cyI0N2uo9vf14aJZKXj7Q70/FnFhdB4auqexkbyKgsuKzEgPMyiiPT82W QX1F1KzNpGk4Q== From: sashiko-bot@kernel.org Subject: Re: [PATCH v5 04/10] md/raid1: don't use write-behind for P2PDMA bios Reply-To: sashiko-reviews@lists.linux.dev To: "Mykola Marzhan" Cc: linux-pci@vger.kernel.org, linux-raid@vger.kernel.org, yukuai@fygo.io In-Reply-To: <20260723204206.76930-5-mykola@meshstor.io> References: <20260723204206.76930-1-mykola@meshstor.io> <20260723204206.76930-5-mykola@meshstor.io> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Thu, 23 Jul 2026 21:01:48 +0000 Message-Id: <20260723210149.583331F000E9@smtp.kernel.org> Precedence: bulk X-Mailing-List: linux-pci@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/20260723204206.7693= 0-1-mykola@meshstor.io?part=3D4