From patchwork Mon Dec 10 17:12:46 2018 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Vivek Goyal X-Patchwork-Id: 10721899 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B180C15A6 for ; Mon, 10 Dec 2018 17:17:45 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 96A0A2ABC3 for ; Mon, 10 Dec 2018 17:17:45 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8B0C82AF3C; Mon, 10 Dec 2018 17:17:45 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=unavailable version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 3282D2ABC3 for ; Mon, 10 Dec 2018 17:17:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728945AbeLJRRd (ORCPT ); Mon, 10 Dec 2018 12:17:33 -0500 Received: from mx1.redhat.com ([209.132.183.28]:52790 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728373AbeLJRNf (ORCPT ); Mon, 10 Dec 2018 12:13:35 -0500 Received: from smtp.corp.redhat.com (int-mx01.intmail.prod.int.phx2.redhat.com [10.5.11.11]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id D6FFC30842D1; Mon, 10 Dec 2018 17:13:34 +0000 (UTC) Received: from horse.redhat.com (unknown [10.18.25.234]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8CA88605D0; Mon, 10 Dec 2018 17:13:34 +0000 (UTC) Received: by horse.redhat.com (Postfix, from userid 10451) id 5329C22425E; Mon, 10 Dec 2018 12:13:30 -0500 (EST) From: Vivek Goyal To: linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org Cc: vgoyal@redhat.com, miklos@szeredi.hu, stefanha@redhat.com, dgilbert@redhat.com, sweil@redhat.com, swhiteho@redhat.com Subject: [PATCH 20/52] Limit number of pages returned by direct_access() Date: Mon, 10 Dec 2018 12:12:46 -0500 Message-Id: <20181210171318.16998-21-vgoyal@redhat.com> In-Reply-To: <20181210171318.16998-1-vgoyal@redhat.com> References: <20181210171318.16998-1-vgoyal@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.11 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.40]); Mon, 10 Dec 2018 17:13:34 +0000 (UTC) Sender: linux-fsdevel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP Truncate number of pages mapped by direct_access() to remain with-in window size. User might request mapping pages beyond window size. Signed-off-by: Vivek Goyal --- fs/fuse/virtio_fs.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) diff --git a/fs/fuse/virtio_fs.c b/fs/fuse/virtio_fs.c index e4d5e0cd41ba..ef1469b38a6d 100644 --- a/fs/fuse/virtio_fs.c +++ b/fs/fuse/virtio_fs.c @@ -449,13 +449,14 @@ static long virtio_fs_direct_access(struct dax_device *dax_dev, pgoff_t pgoff, { struct virtio_fs *fs = dax_get_private(dax_dev); phys_addr_t offset = PFN_PHYS(pgoff); + size_t max_nr_pages = fs->window_len/PAGE_SIZE - pgoff; if (kaddr) *kaddr = fs->window_kaddr + offset; if (pfn) *pfn = phys_to_pfn_t(fs->window_phys_addr + offset, PFN_DEV | PFN_MAP); - return nr_pages; + return nr_pages > max_nr_pages ? max_nr_pages : nr_pages; } static size_t virtio_fs_copy_from_iter(struct dax_device *dax_dev,