From: Elena Reshetova <elena.reshetova@intel.com>
To: axboe@kernel.dk
Cc: james.bottomley@hansenpartnership.com,
linux-kernel@vger.kernel.org, linux-block@vger.kernel.org,
linux-scsi@vger.kernel.org, linux-btrfs@vger.kernel.org,
peterz@infradead.org, gregkh@linuxfoundation.org,
keescook@chromium.org, fujita.tomonori@lab.ntt.co.jp,
mingo@redhat.com, clm@fb.com, jbacik@fb.com, dsterba@suse.com,
Elena Reshetova <elena.reshetova@intel.com>,
Hans Liljestrand <ishkamiel@gmail.com>,
David Windsor <dwindsor@gmail.com>
Subject: [PATCH 3/5] block: convert blkcg_gq.refcnt from atomic_t to refcount_t
Date: Tue, 27 Jun 2017 14:39:58 +0300 [thread overview]
Message-ID: <1498563601-10949-4-git-send-email-elena.reshetova@intel.com> (raw)
In-Reply-To: <1498563601-10949-1-git-send-email-elena.reshetova@intel.com>
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 <elena.reshetova@intel.com>
Signed-off-by: Hans Liljestrand <ishkamiel@gmail.com>
Signed-off-by: Kees Cook <keescook@chromium.org>
Signed-off-by: David Windsor <dwindsor@gmail.com>
---
block/blk-cgroup.c | 2 +-
include/linux/blk-cgroup.h | 9 ++++-----
2 files changed, 5 insertions(+), 6 deletions(-)
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 0480892..3762908 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -107,7 +107,7 @@ static struct blkcg_gq *blkg_alloc(struct blkcg *blkcg, struct request_queue *q,
blkg->q = q;
INIT_LIST_HEAD(&blkg->q_node);
blkg->blkcg = blkcg;
- atomic_set(&blkg->refcnt, 1);
+ refcount_set(&blkg->refcnt, 1);
/* root blkg uses @q->root_rl, init rl only for !root blkgs */
if (blkcg != &blkcg_root) {
diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h
index 01b62e7..e54f048 100644
--- a/include/linux/blk-cgroup.h
+++ b/include/linux/blk-cgroup.h
@@ -19,6 +19,7 @@
#include <linux/radix-tree.h>
#include <linux/blkdev.h>
#include <linux/atomic.h>
+#include <linux/refcount.h>
/* percpu_counter batch for blkg_[rw]stats, per-cpu drift doesn't matter */
#define BLKG_STAT_CPU_BATCH (INT_MAX / 2)
@@ -122,7 +123,7 @@ struct blkcg_gq {
struct request_list rl;
/* reference count */
- atomic_t refcnt;
+ refcount_t refcnt;
/* is this blkg online? protected by both blkcg and q locks */
bool online;
@@ -354,8 +355,7 @@ static inline int blkg_path(struct blkcg_gq *blkg, char *buf, int buflen)
*/
static inline void blkg_get(struct blkcg_gq *blkg)
{
- WARN_ON_ONCE(atomic_read(&blkg->refcnt) <= 0);
- atomic_inc(&blkg->refcnt);
+ refcount_inc(&blkg->refcnt);
}
void __blkg_release_rcu(struct rcu_head *rcu);
@@ -366,8 +366,7 @@ void __blkg_release_rcu(struct rcu_head *rcu);
*/
static inline void blkg_put(struct blkcg_gq *blkg)
{
- WARN_ON_ONCE(atomic_read(&blkg->refcnt) <= 0);
- if (atomic_dec_and_test(&blkg->refcnt))
+ if (refcount_dec_and_test(&blkg->refcnt))
call_rcu(&blkg->rcu_head, __blkg_release_rcu);
}
--
2.7.4
next prev parent reply other threads:[~2017-06-27 11:41 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-06-27 11:39 [PATCH 0/5] v3 block subsystem refcounter conversions Elena Reshetova
2017-06-27 11:39 ` [PATCH 1/5] block: convert bio.__bi_cnt from atomic_t to refcount_t Elena Reshetova
2017-06-27 11:39 ` [PATCH 2/5] block: convert blk_queue_tag.refcnt " Elena Reshetova
2017-06-27 11:39 ` Elena Reshetova [this message]
2017-06-27 11:39 ` [PATCH 4/5] block: convert io_context.active_ref " Elena Reshetova
2017-06-27 11:40 ` [PATCH 5/5] block: convert bsg_device.ref_count " Elena Reshetova
2017-06-27 13:26 ` [PATCH 0/5] v3 block subsystem refcounter conversions Jens Axboe
2017-06-27 22:13 ` Kees Cook
2017-06-28 11:58 ` Reshetova, Elena
2017-06-28 12:51 ` Jens Axboe
2017-06-29 7:38 ` Reshetova, Elena
-- strict thread matches above, loose matches on Subject: below --
2017-04-20 11:27 [PATCH 0/5] v2: " Elena Reshetova
2017-04-20 11:27 ` [PATCH 3/5] block: convert blkcg_gq.refcnt from atomic_t to refcount_t Elena Reshetova
2017-02-20 11:16 [PATCH 0/5] block subsystem refcounter conversions Elena Reshetova
2017-02-20 11:16 ` [PATCH 3/5] block: convert blkcg_gq.refcnt from atomic_t to refcount_t Elena Reshetova
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