Re: fix rcu annotations noise in cred.h

David Howells
2011-08-08T12:54:48Z

Paul E. McKenney <paulmck@linux.vnet.ibm.com> wrote:

> This is indeed what rcu_dereference_protected() is intended for.

How about the attached patch?

David
---
From: David Howells <dhowells@redhat.com>
Subject: [PATCH] CRED: Restore const to current_cred()

Commit 3295514841c2112d94451ba5deaf54f5afb78ea9 accidentally dropped the const
of current->cred inside current_cred() by the insertion of a cast to deal with
an RCU annotation loss warning from sparce.

Use an appropriate RCU wrapper instead so as not to lose the const.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Al Viro <viro@zeniv.linux.org.uk>
---

include/linux/cred.h | 2 +-
1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/include/linux/cred.h b/include/linux/cred.h
index 98f46ef..8e2fd44 100644
--- a/include/linux/cred.h
+++ b/include/linux/cred.h
@@ -269,7 +269,7 @@ static inline void put_cred(const struct cred *_cred)
* since nobody else can modify it.
*/
#define current_cred() \
- (*(__force struct cred **)&current->cred)
+ rcu_dereference_protected(current->cred, 1)

/**
* __task_cred - Access a task's objective credentials