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 8CE0F3815F8; Sun, 26 Jul 2026 12:01:12 +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=1785067273; cv=none; b=gaoDURpzbBzZoh8D0xpTBBqdUNWx3ze5AkAxCzQ1VDPm+Jfzhqmv88LW2EkPDJsoXlXWZ4oqARQtYA50FL39G9qm0TNCGEg5UyB5VnYreg8+NscTunQCLXwtYuC6h7d/ENbEzSW6ijhiXXvYBIULE44+VJZc+crSdDbFn7jVcMI= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1785067273; c=relaxed/simple; bh=LvUSu1UkDCLvUe007YN9P7sOYBPpUqslSHPEiZQkGys=; h=From:Subject:To:Cc:In-Reply-To:References:Content-Type:Date: Message-Id; b=r/0jl8OsbmdQirWtIqkV117k3dFL9Jg4bZuO8OEWLpAaF8dZHDpdReCpUfbysKtgZ424tHdof6voslIoqhpbjSujnsVnqjf6zv0qxsvJf3nftL5hVHUtHg6rKQ5w62xYGobxHBMNfMUj2lie7omTlAWJT9DOhNm/cfKPtAh22/8= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=Sem14vP8; 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="Sem14vP8" Received: by smtp.kernel.org (Postfix) with ESMTPSA id B259E1F000E9; Sun, 26 Jul 2026 12:01:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1785067271; bh=oYTrwVHmgtFFJlN1f2V+xGnSZnwJ2Hvnv+F7LzDdFxU=; h=From:Subject:Reply-To:To:Cc:In-Reply-To:References:Date; b=Sem14vP8+M2zzsseNlQcwELnjf2KIXEymUra1a7cKffF19g5cgs4/JIKiCw9tRbZJ EZemHfF0uOKMFFVUySx8zKEIpfGdW+UcSI/B6RZYnVnEq/3TpWPdyzKMONsZKatVcK U7SYO/Fc1RYiS80m9DqFY/vJGEHFNW8Y7buJlsSr/txUV0wI8B52TrsthTk+P8WsFo islWg6VM87Eds4ReemWUVCZhYJaP79Xc1ZoCyqfSjcEKyLg0qN6dVP0Ku3t4Kj4UfO jPD2rr75rPSeXAFTo4ZsY8CekUyouq09b3Dl8oePJbNPNTJ99Czja5OamjkFemURzJ pUU+fXXwgrm4A== From: sashiko-bot@kernel.org Subject: Re: [PATCH v6 04/12] md/raid1: don't use write-behind for P2PDMA bios Reply-To: sashiko-reviews@lists.linux.dev To: "Mykola Marzhan" Cc: linux-raid@vger.kernel.org, yukuai@fygo.io, linux-pci@vger.kernel.org In-Reply-To: <20260726113229.2154269-5-mykola@meshstor.io> References: <20260726113229.2154269-1-mykola@meshstor.io> <20260726113229.2154269-5-mykola@meshstor.io> Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Date: Sun, 26 Jul 2026 12:01:11 +0000 Message-Id: <20260726120111.B259E1F000E9@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/20260726113229.2154= 269-1-mykola@meshstor.io?part=3D4