Re: [PATCH 08/29] drivers, md: convert mddev.active from atomic_t to refcount_t
From: Shaohua Li <shli@kernel.org>
Date: 2017-03-07 19:11:24
Also in:
linux-bcache, linux-media, linux-pci, linux-raid, linux-s390, linux-scsi, linux-serial, lkml
On Mon, Mar 06, 2017 at 04:20:55PM +0200, Elena Reshetova wrote:
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.
Looks good. Let me know how do you want to route the patch to upstream.
quoted hunk ↗ jump to hunk
Signed-off-by: Elena Reshetova <elena.reshetova@intel.com> Signed-off-by: Hans Liljestrand <redacted> Signed-off-by: Kees Cook <redacted> Signed-off-by: David Windsor <redacted> --- drivers/md/md.c | 6 +++--- drivers/md/md.h | 3 ++- 2 files changed, 5 insertions(+), 4 deletions(-)diff --git a/drivers/md/md.c b/drivers/md/md.c index 985374f..94c8ebf 100644 --- a/drivers/md/md.c +++ b/drivers/md/md.c@@ -449,7 +449,7 @@ EXPORT_SYMBOL(md_unplug); static inline struct mddev *mddev_get(struct mddev *mddev) { - atomic_inc(&mddev->active); + refcount_inc(&mddev->active); return mddev; }@@ -459,7 +459,7 @@ static void mddev_put(struct mddev *mddev) { struct bio_set *bs = NULL; - if (!atomic_dec_and_lock(&mddev->active, &all_mddevs_lock)) + if (!refcount_dec_and_lock(&mddev->active, &all_mddevs_lock)) return; if (!mddev->raid_disks && list_empty(&mddev->disks) && mddev->ctime == 0 && !mddev->hold_active) {@@ -495,7 +495,7 @@ void mddev_init(struct mddev *mddev) INIT_LIST_HEAD(&mddev->all_mddevs); setup_timer(&mddev->safemode_timer, md_safemode_timeout, (unsigned long) mddev); - atomic_set(&mddev->active, 1); + refcount_set(&mddev->active, 1); atomic_set(&mddev->openers, 0); atomic_set(&mddev->active_io, 0); spin_lock_init(&mddev->lock);diff --git a/drivers/md/md.h b/drivers/md/md.h index b8859cb..4811663 100644 --- a/drivers/md/md.h +++ b/drivers/md/md.h@@ -22,6 +22,7 @@ #include <linux/list.h> #include <linux/mm.h> #include <linux/mutex.h> +#include <linux/refcount.h> #include <linux/timer.h> #include <linux/wait.h> #include <linux/workqueue.h>@@ -360,7 +361,7 @@ struct mddev { */ struct mutex open_mutex; struct mutex reconfig_mutex; - atomic_t active; /* general refcount */ + refcount_t active; /* general refcount */ atomic_t openers; /* number of active opens */ int changed; /* True if we might need to-- 2.7.4 -- To unsubscribe from this list: send the line "unsubscribe linux-raid" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html