From patchwork Mon Mar 6 14:20:54 2017 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Reshetova, Elena" X-Patchwork-Id: 9606855 X-Patchwork-Delegate: bhelgaas@google.com 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 069AE60414 for ; Mon, 6 Mar 2017 14:44:46 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id EEEAA25D9E for ; Mon, 6 Mar 2017 14:44:45 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id E33E426907; Mon, 6 Mar 2017 14:44:45 +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=-6.9 required=2.0 tests=BAYES_00,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 A09F225D9E for ; Mon, 6 Mar 2017 14:44:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932115AbdCFOem (ORCPT ); Mon, 6 Mar 2017 09:34:42 -0500 Received: from mga07.intel.com ([134.134.136.100]:29441 "EHLO mga07.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751248AbdCFOY4 (ORCPT ); Mon, 6 Mar 2017 09:24:56 -0500 Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga105.jf.intel.com with ESMTP; 06 Mar 2017 06:22:10 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.35,254,1484035200"; d="scan'208";a="72745972" Received: from rzetikx-mobl.ger.corp.intel.com (HELO elena-ThinkPad-X230.ger.corp.intel.com) ([10.249.41.1]) by fmsmga005.fm.intel.com with ESMTP; 06 Mar 2017 06:22:04 -0800 From: Elena Reshetova To: gregkh@linuxfoundation.org Cc: linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, netdev@vger.kernel.org, linux1394-devel@lists.sourceforge.net, linux-bcache@vger.kernel.org, linux-raid@vger.kernel.org, linux-media@vger.kernel.org, devel@linuxdriverproject.org, linux-pci@vger.kernel.org, linux-s390@vger.kernel.org, fcoe-devel@open-fcoe.org, linux-scsi@vger.kernel.org, open-iscsi@googlegroups.com, devel@driverdev.osuosl.org, target-devel@vger.kernel.org, linux-serial@vger.kernel.org, linux-usb@vger.kernel.org, peterz@infradead.org, Elena Reshetova , Hans Liljestrand , Kees Cook , David Windsor Subject: [PATCH 07/29] drivers, md: convert dm_dev_internal.count from atomic_t to refcount_t Date: Mon, 6 Mar 2017 16:20:54 +0200 Message-Id: <1488810076-3754-8-git-send-email-elena.reshetova@intel.com> X-Mailer: git-send-email 2.7.4 In-Reply-To: <1488810076-3754-1-git-send-email-elena.reshetova@intel.com> References: <1488810076-3754-1-git-send-email-elena.reshetova@intel.com> Sender: linux-pci-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-pci@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 --- drivers/md/dm-table.c | 6 +++--- drivers/md/dm.h | 3 ++- 2 files changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/md/dm-table.c b/drivers/md/dm-table.c index 3ad16d9..d2e2741 100644 --- a/drivers/md/dm-table.c +++ b/drivers/md/dm-table.c @@ -416,15 +416,15 @@ int dm_get_device(struct dm_target *ti, const char *path, fmode_t mode, return r; } - atomic_set(&dd->count, 0); + refcount_set(&dd->count, 1); list_add(&dd->list, &t->devices); } else if (dd->dm_dev->mode != (mode | dd->dm_dev->mode)) { r = upgrade_mode(dd, mode, t->md); if (r) return r; + refcount_inc(&dd->count); } - atomic_inc(&dd->count); *result = dd->dm_dev; return 0; @@ -478,7 +478,7 @@ void dm_put_device(struct dm_target *ti, struct dm_dev *d) dm_device_name(ti->table->md), d->name); return; } - if (atomic_dec_and_test(&dd->count)) { + if (refcount_dec_and_test(&dd->count)) { dm_put_table_device(ti->table->md, d); list_del(&dd->list); kfree(dd); diff --git a/drivers/md/dm.h b/drivers/md/dm.h index f298b01..63b8142 100644 --- a/drivers/md/dm.h +++ b/drivers/md/dm.h @@ -19,6 +19,7 @@ #include #include #include +#include #include "dm-stats.h" @@ -38,7 +39,7 @@ */ struct dm_dev_internal { struct list_head list; - atomic_t count; + refcount_t count; struct dm_dev *dm_dev; };