From a4b51a9f83c6d359ff8fc0c66009283b6fdeeaf8 Mon Sep 17 00:00:00 2001 From: Elena Reshetova Date: Fri, 20 Oct 2017 10:23:40 +0300 Subject: drivers, net, mlx5: convert mlx5_cq.refcount from atomic_t to refcount_t atomic_t variables are currently used to implement reference counters with the following properties: - counter is initialized to 1 using atomic_set() - a resource is freed upon counter reaching zero - once counter reaches zero, its further increments aren't allowed - counter schema uses basic atomic operations (set, inc, inc_not_zero, dec_and_test, etc.) Such atomic variables should be converted to a newly provided refcount_t type and API that prevents accidental counter overflows and underflows. This is important since overflows and underflows can lead to use-after-free situation and be exploitable. The variable mlx5_cq.refcount is used as pure reference counter. Convert it to refcount_t and fix up the operations. Suggested-by: Kees Cook Reviewed-by: David Windsor Reviewed-by: Hans Liljestrand Signed-off-by: Elena Reshetova Signed-off-by: David S. Miller --- include/linux/mlx5/cq.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'include') diff --git a/include/linux/mlx5/cq.h b/include/linux/mlx5/cq.h index 95898847c7d4..6a57ec2f1ef7 100644 --- a/include/linux/mlx5/cq.h +++ b/include/linux/mlx5/cq.h @@ -35,7 +35,7 @@ #include #include - +#include struct mlx5_core_cq { u32 cqn; @@ -43,7 +43,7 @@ struct mlx5_core_cq { __be32 *set_ci_db; __be32 *arm_db; struct mlx5_uars_page *uar; - atomic_t refcount; + refcount_t refcount; struct completion free; unsigned vector; unsigned int irqn; -- cgit v1.2.3