fix rcu annotations noise in cred.h

Al Viro
2011-08-07T17:55:18Z

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 <viro@zeniv.linux.org.uk>
---
diff --git a/include/linux/cred.h b/include/linux/cred.h
index 48e82af..98f46ef 100644
--- 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))