libceph: convert ceph_pagelist.refcnt from atomic_t to refcount_t

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>
Signed-off-by: Ilya Dryomov <idryomov@gmail.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/include/linux/ceph/pagelist.h b/include/linux/ceph/pagelist.h
index 13d71fe18b0c..75a7db21457d 100644
--- a/include/linux/ceph/pagelist.h
+++ b/include/linux/ceph/pagelist.h
@@ -2,7 +2,7 @@
 #define __FS_CEPH_PAGELIST_H
 
 #include <asm/byteorder.h>
-#include <linux/atomic.h>
+#include <linux/refcount.h>
 #include <linux/list.h>
 #include <linux/types.h>
 
@@ -13,7 +13,7 @@ struct ceph_pagelist {
 	size_t room;
 	struct list_head free_list;
 	size_t num_pages_free;
-	atomic_t refcnt;
+	refcount_t refcnt;
 };
 
 struct ceph_pagelist_cursor {
@@ -30,7 +30,7 @@ static inline void ceph_pagelist_init(struct ceph_pagelist *pl)
 	pl->room = 0;
 	INIT_LIST_HEAD(&pl->free_list);
 	pl->num_pages_free = 0;
-	atomic_set(&pl->refcnt, 1);
+	refcount_set(&pl->refcnt, 1);
 }
 
 extern void ceph_pagelist_release(struct ceph_pagelist *pl);