From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754638AbdCFOlm (ORCPT ); Mon, 6 Mar 2017 09:41:42 -0500 Received: from mga01.intel.com ([192.55.52.88]:10814 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932434AbdCFOfc (ORCPT ); Mon, 6 Mar 2017 09:35:32 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.35,254,1484035200"; d="scan'208";a="72746333" 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 18/29] drivers, s390: convert urdev.ref_count from atomic_t to refcount_t Date: Mon, 6 Mar 2017 16:21:05 +0200 Message-Id: <1488810076-3754-19-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/s390/char/vmur.c | 8 ++++---- drivers/s390/char/vmur.h | 4 +++- 2 files changed, 7 insertions(+), 5 deletions(-) diff --git a/drivers/s390/char/vmur.c b/drivers/s390/char/vmur.c index 04aceb6..ced8151 100644 --- a/drivers/s390/char/vmur.c +++ b/drivers/s390/char/vmur.c @@ -110,7 +110,7 @@ static struct urdev *urdev_alloc(struct ccw_device *cdev) mutex_init(&urd->io_mutex); init_waitqueue_head(&urd->wait); spin_lock_init(&urd->open_lock); - atomic_set(&urd->ref_count, 1); + refcount_set(&urd->ref_count, 1); urd->cdev = cdev; get_device(&cdev->dev); return urd; @@ -126,7 +126,7 @@ static void urdev_free(struct urdev *urd) static void urdev_get(struct urdev *urd) { - atomic_inc(&urd->ref_count); + refcount_inc(&urd->ref_count); } static struct urdev *urdev_get_from_cdev(struct ccw_device *cdev) @@ -159,7 +159,7 @@ static struct urdev *urdev_get_from_devno(u16 devno) static void urdev_put(struct urdev *urd) { - if (atomic_dec_and_test(&urd->ref_count)) + if (refcount_dec_and_test(&urd->ref_count)) urdev_free(urd); } @@ -946,7 +946,7 @@ static int ur_set_offline_force(struct ccw_device *cdev, int force) rc = -EBUSY; goto fail_urdev_put; } - if (!force && (atomic_read(&urd->ref_count) > 2)) { + if (!force && (refcount_read(&urd->ref_count) > 2)) { /* There is still a user of urd (e.g. ur_open) */ TRACE("ur_set_offline: BUSY\n"); rc = -EBUSY; diff --git a/drivers/s390/char/vmur.h b/drivers/s390/char/vmur.h index fa320ad..35ea9d1 100644 --- a/drivers/s390/char/vmur.h +++ b/drivers/s390/char/vmur.h @@ -11,6 +11,8 @@ #ifndef _VMUR_H_ #define _VMUR_H_ +#include + #define DEV_CLASS_UR_I 0x20 /* diag210 unit record input device class */ #define DEV_CLASS_UR_O 0x10 /* diag210 unit record output device class */ /* @@ -69,7 +71,7 @@ struct urdev { size_t reclen; /* Record length for *write* CCWs */ int class; /* VM device class */ int io_request_rc; /* return code from I/O request */ - atomic_t ref_count; /* reference counter */ + refcount_t ref_count; /* reference counter */ wait_queue_head_t wait; /* wait queue to serialize open */ int open_flag; /* "urdev is open" flag */ spinlock_t open_lock; /* serialize critical sections */ -- 2.7.4