From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: 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 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> Sender: linux-fsdevel-owner@vger.kernel.org List-ID: 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, -- 2.13.6