fix rcu annotations noise in cred.h

task->cred is declared as __rcu, and access to other tasks' ->cred is, indeed, protected. Access to current->cred does not need rcu_dereference() at all, since only the task itself can change its ->cred. sparse, of course, has no way of knowing that... Add force-cast in current_cred(), make current_fsuid() et.al. use it. Signed-off-by: Al Viro <[email protected]> Signed-off-by: Linus Torvalds <[email protected]>
rtvt123 · Aug 7, 2011 · 3295514 · 3295514
1 parent 7813b94
commit 3295514
Showing 1 changed file with 6 additions and 5 deletions.
diff --git a/include/linux/cred.h b/include/linux/cred.h
@@ -265,10 +265,11 @@ static inline void put_cred(const struct cred *_cred)
 /**
  * current_cred - Access the current task's subjective credentials
  *
- * Access the subjective credentials of the current task.
+ * Access the subjective credentials of the current task.  RCU-safe,
+ * since nobody else can modify it.
  */
 #define current_cred() \
-	(current->cred)
+	(*(__force struct cred **)&current->cred)
 
 /**
  * __task_cred - Access a task's objective credentials
@@ -307,7 +308,7 @@ static inline void put_cred(const struct cred *_cred)
 ({							\
 	struct user_struct *__u;			\
 	struct cred *__cred;				\
-	__cred = (struct cred *) current_cred();	\
+	__cred = current_cred();			\
 	__u = get_uid(__cred->user);			\
 	__u;						\
 })
@@ -322,7 +323,7 @@ static inline void put_cred(const struct cred *_cred)
 ({							\
 	struct group_info *__groups;			\
 	struct cred *__cred;				\
-	__cred = (struct cred *) current_cred();	\
+	__cred = current_cred();			\
 	__groups = get_group_info(__cred->group_info);	\
 	__groups;					\
 })
@@ -341,7 +342,7 @@ static inline void put_cred(const struct cred *_cred)
 
 #define current_cred_xxx(xxx)			\
 ({						\
-	current->cred->xxx;			\
+	current_cred()->xxx;			\
 })
 
 #define current_uid()		(current_cred_xxx(uid))