From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (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 EC91723DEB3; Tue, 10 Dec 2024 11:22:43 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=198.137.202.133 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733829765; cv=none; b=hktXacf5FoPrZUdWa7Ezvq/8qh3UXaHlC3C1luKMREdrXkLHm9pSuHInNYIKBLHyK47TzUXDH9NNbNo8NmelmhU0X9gdRzKtG6lmbV2ANMdY5oDrAlaYtIHHc3hcxULnWwyVwVc5VGzGo1GElxbolzpSGbYiwPF5p/3IZCOs5us= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1733829765; c=relaxed/simple; bh=3e8IArdZerzmiqrl5a5fgUupmvK8sP8WRrrkD6Ir9WA=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=DYXHEnuQQ8f+CqQN0HUpKcKlcZzDi/VNdsuH+J0S3dtzzPJTjMFw2pTMa8UgcT+L3Ap24FHcio/3yL+8azkr2yb05mj/LHosdIamhvNtnjh5gI8KItpf1ZRALBGqdbGrGyW6AhUNs6dZ6lHNn7+oTmk08d24wd0s1p8MZkbIg7I= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b=CQ6khhXd; arc=none smtp.client-ip=198.137.202.133 Authentication-Results: smtp.subspace.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: smtp.subspace.kernel.org; spf=none smtp.mailfrom=bombadil.srs.infradead.org Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=infradead.org header.i=@infradead.org header.b="CQ6khhXd" DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20210309; h=In-Reply-To:Content-Type:MIME-Version :References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=WwO2WwMmgUHVrbMnAEHD/hczXHCTvxPmE53VtScaPRI=; b=CQ6khhXdcNxbSInmE0iCXUYCVp I3AKvSwOHbA356SDw+74PdaBpNxfCNg4EnYBwktitp31HA5s9fnyh+WIONLihERbtPi3ut1Dy+llM Uvf3MoyQyL2iXDOJ0d3YYhLkmYVTs2lyoW1+ytevXnHly2pS9mr7r3ct74HRcJS8bCBcLos9QrBxm u6tZO1RpuKQQL8NceSOnBngMYudGfBvJVPCFXhcFj2SRoPs5/Cp14UzE6TbgOcil8mEckYISEu5dH wYxfxMowNVxz1S+dUOJykYiEV+61er0QeBQ40Yh8HsKb28B0DACwhr9URIJ+tC3nvg9ffnNVbfO8m H44GYjXQ==; Received: from hch by bombadil.infradead.org with local (Exim 4.98 #2 (Red Hat Linux)) id 1tKyKB-0000000BIlk-2Dj3; Tue, 10 Dec 2024 11:22:43 +0000 Date: Tue, 10 Dec 2024 03:22:43 -0800 From: Christoph Hellwig To: Jens Axboe Cc: linux-mm@kvack.org, linux-fsdevel@vger.kernel.org, hannes@cmpxchg.org, clm@meta.com, linux-kernel@vger.kernel.org, willy@infradead.org, kirill@shutemov.name, bfoster@redhat.com Subject: Re: [PATCH 07/12] fs: add RWF_UNCACHED iocb and FOP_UNCACHED file_operations flag Message-ID: References: <20241203153232.92224-2-axboe@kernel.dk> <20241203153232.92224-9-axboe@kernel.dk> Precedence: bulk X-Mailing-List: linux-fsdevel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20241203153232.92224-9-axboe@kernel.dk> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Tue, Dec 03, 2024 at 08:31:43AM -0700, Jens Axboe wrote: > + if (flags & RWF_UNCACHED) { > + /* file system must support it */ > + if (!(ki->ki_filp->f_op->fop_flags & FOP_UNCACHED)) > + return -EOPNOTSUPP; > + /* DAX mappings not supported */ > + if (IS_DAX(ki->ki_filp->f_mapping->host)) > + return -EOPNOTSUPP; I'd argue that DAX is always uncached and could just ignore the flag. Same for direct I/O.