From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754204AbdCFO3R (ORCPT ); Mon, 6 Mar 2017 09:29:17 -0500 Received: from mga14.intel.com ([192.55.52.115]:37943 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753359AbdCFOZL (ORCPT ); Mon, 6 Mar 2017 09:25:11 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.35,254,1484035200"; d="scan'208";a="72745945" 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 06/29] drivers, md: convert dm_cache_metadata.ref_count from atomic_t to refcount_t Date: Mon, 6 Mar 2017 16:20:53 +0200 Message-Id: <1488810076-3754-7-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-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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-cache-metadata.c | 9 +++++---- 1 file changed, 5 insertions(+), 4 deletions(-) diff --git a/drivers/md/dm-cache-metadata.c b/drivers/md/dm-cache-metadata.c index e4c2c1a..6d26e71 100644 --- a/drivers/md/dm-cache-metadata.c +++ b/drivers/md/dm-cache-metadata.c @@ -13,6 +13,7 @@ #include "persistent-data/dm-transaction-manager.h" #include +#include /*----------------------------------------------------------------*/ @@ -102,7 +103,7 @@ struct cache_disk_superblock { } __packed; struct dm_cache_metadata { - atomic_t ref_count; + refcount_t ref_count; struct list_head list; unsigned version; @@ -756,7 +757,7 @@ static struct dm_cache_metadata *metadata_open(struct block_device *bdev, } cmd->version = metadata_version; - atomic_set(&cmd->ref_count, 1); + refcount_set(&cmd->ref_count, 1); init_rwsem(&cmd->root_lock); cmd->bdev = bdev; cmd->data_block_size = data_block_size; @@ -794,7 +795,7 @@ static struct dm_cache_metadata *lookup(struct block_device *bdev) list_for_each_entry(cmd, &table, list) if (cmd->bdev == bdev) { - atomic_inc(&cmd->ref_count); + refcount_inc(&cmd->ref_count); return cmd; } @@ -865,7 +866,7 @@ struct dm_cache_metadata *dm_cache_metadata_open(struct block_device *bdev, void dm_cache_metadata_close(struct dm_cache_metadata *cmd) { - if (atomic_dec_and_test(&cmd->ref_count)) { + if (refcount_dec_and_test(&cmd->ref_count)) { mutex_lock(&table_lock); list_del(&cmd->list); mutex_unlock(&table_lock); -- 2.7.4