From patchwork Fri Mar 3 08:55:22 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Reshetova, Elena" X-Patchwork-Id: 9602261 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id D1A42602B4 for ; Fri, 3 Mar 2017 09:04:42 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id C631E285F5 for ; Fri, 3 Mar 2017 09:04:42 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id BAC75285FF; Fri, 3 Mar 2017 09:04:42 +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=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham 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 6B831285F5 for ; Fri, 3 Mar 2017 09:04:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751643AbdCCJC3 (ORCPT ); Fri, 3 Mar 2017 04:02:29 -0500 Received: from mga02.intel.com ([134.134.136.20]:7352 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751394AbdCCJCY (ORCPT ); Fri, 3 Mar 2017 04:02:24 -0500 Received: from fmsmga002.fm.intel.com ([10.253.24.26]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 03 Mar 2017 00:56:23 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.35,236,1484035200"; d="scan'208";a="1137385170" Received: from fkowalsk-mobl.ger.corp.intel.com (HELO elena-ThinkPad-X230.ger.corp.intel.com) ([10.252.33.72]) by fmsmga002.fm.intel.com with ESMTP; 03 Mar 2017 00:56:19 -0800 From: Elena Reshetova To: linux-kernel@vger.kernel.org Cc: linux-fsdevel@vger.kernel.org, linux-btrfs@vger.kernel.org, peterz@infradead.org, gregkh@linuxfoundation.org, jbacik@fb.com, clm@fb.com, dsterba@suse.com, Elena Reshetova , Hans Liljestrand , Kees Cook , David Windsor Subject: [PATCH 13/17] fs, btrfs: convert scrub_page.refs from atomic_t to refcount_t Date: Fri, 3 Mar 2017 10:55:22 +0200 Message-Id: <1488531326-21271-14-git-send-email-elena.reshetova@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1488531326-21271-1-git-send-email-elena.reshetova@intel.com> References: <1488531326-21271-1-git-send-email-elena.reshetova@intel.com> Sender: linux-btrfs-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-btrfs@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP refcount_t type and corresponding API should be used instead of atomic_t when the variable is used as a reference counter. This allows to avoid accidental refcounter overflows that might lead to use-after-free situations. Signed-off-by: Elena Reshetova Signed-off-by: Hans Liljestrand Signed-off-by: Kees Cook Signed-off-by: David Windsor --- fs/btrfs/scrub.c | 6 +++--- 1 file changed, 3 insertions(+), 3 deletions(-) diff --git a/fs/btrfs/scrub.c b/fs/btrfs/scrub.c index c9406bf..8299f64 100644 --- a/fs/btrfs/scrub.c +++ b/fs/btrfs/scrub.c @@ -79,7 +79,7 @@ struct scrub_page { u64 logical; u64 physical; u64 physical_for_dev_replace; - atomic_t refs; + refcount_t refs; struct { unsigned int mirror_num:8; unsigned int have_csum:1; @@ -2017,12 +2017,12 @@ static void scrub_block_put(struct scrub_block *sblock) static void scrub_page_get(struct scrub_page *spage) { - atomic_inc(&spage->refs); + refcount_inc(&spage->refs); } static void scrub_page_put(struct scrub_page *spage) { - if (atomic_dec_and_test(&spage->refs)) { + if (refcount_dec_and_test(&spage->refs)) { if (spage->page) __free_page(spage->page); kfree(spage);