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 1658B22576A for ; Thu, 6 Mar 2025 15:26:53 +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=1741274816; cv=none; b=g8dV31OowAzecT79en/f1rykWkq7343RhEMtT8jd3rdzoFxzKAuzzHtSdmtOn/+2KOj3KEfsYQPKT2dfmhGyX3X7HhSY1wIzZaPXWX23UMLE4Z0IBvNnfGYJ2aIGGSCH2+ozMrpinB290Vhye6YNUhJl5oejr5wfuWpjIWZDOgU= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1741274816; c=relaxed/simple; bh=nvJRaj+K8dARRU9iy0o2abF8QxEH+WyKBIUE7J+Q3P8=; h=Date:From:To:Cc:Subject:Message-ID:References:MIME-Version: Content-Type:Content-Disposition:In-Reply-To; b=j4NGtG3ZzCh+2pszFH9tJgwX0GK5azxsyIpVCkUNx6/HwE1OQrjXc6ZiclwOcGb8yATwaYCmnmhazrWJYLeOTHiHm6GeyxjUUGZWYh74TKKV6xKHJRDOtuGPzKZ7/MDZqxNlna9Ct5DLJIsLbzq6jXOxXLmxnz0haBe8B8F6ThA= 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=sI6NcA05; 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="sI6NcA05" 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=5T9N2ceD22uhoxgQHNN1kfiGf/LRNSJbimPTyWXF3I8=; b=sI6NcA052+NV1hoDKNnd5OUSzY DQKXgRufvgJahYNPLuwWljgFcC94Ad05DdEN5UmzXxrIIMDTjXCLENcnnoXR0o91YQcvXkiZf23ff my9jo9Ixt48xbBFDQXZ4E2/5KN42U+nTY1+IbjPSVFq3HR5ctdBCTBRFy6CfrA3zedCOfgqIxq4bd NLQ1u2YZp+FPxanq8ElxF0Lrq7JAnR0b0D0fiVwYw/cmyIJ78urr09YUKQtc3PrLOFQHdiJpD8yFg Rpn+GkKvd5e3SBEs85Yw5smpf2p6ZVbhfZABiCKx3GoV/oM5zZsclzP/8vWrTuFPP4GywF9xAlybR Uk5O+8tQ==; Received: from hch by bombadil.infradead.org with local (Exim 4.98 #2 (Red Hat Linux)) id 1tqD7c-0000000BJhb-1v7n; Thu, 06 Mar 2025 15:26:52 +0000 Date: Thu, 6 Mar 2025 07:26:52 -0800 From: Christoph Hellwig To: Sooyong Suk Cc: viro@zeniv.linux.org.uk, linux-kernel@vger.kernel.org, akpm@linux-foundation.org, linux-mm@kvack.org, jaewon31.kim@gmail.com, spssyr@gmail.com Subject: Re: [RFC PATCH] block, fs: use FOLL_LONGTERM as gup_flags for direct IO Message-ID: References: <20250306074056.246582-1-s.suk@samsung.com> Precedence: bulk X-Mailing-List: linux-kernel@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: <20250306074056.246582-1-s.suk@samsung.com> X-SRS-Rewrite: SMTP reverse-path rewritten from by bombadil.infradead.org. See http://www.infradead.org/rpr.html On Thu, Mar 06, 2025 at 04:40:56PM +0900, Sooyong Suk wrote: > There are GUP references to pages that are serving as direct IO buffers. > Those pages can be allocated from CMA pageblocks despite they can be > pinned until the DIO is completed. direct I/O is eactly the case that is not FOLL_LONGTERM and one of the reasons to even have the flag. So big fat no to this. You also completely failed to address the relevant mailinglist and maintainers.