nfsd: silence sparse warning about accessing credentials

sparse says:

    fs/nfsd/auth.c:31:38: warning: incorrect type in argument 1 (different address spaces)
    fs/nfsd/auth.c:31:38:    expected struct cred const *cred
    fs/nfsd/auth.c:31:38:    got struct cred const [noderef] <asn:4>*real_cred

Add a new accessor for the ->real_cred and use that to fetch the
pointer. Accessing current->real_cred directly is actually quite safe
since we know that they can't go away so this is mostly a cosmetic fixup
to silence sparse.

Signed-off-by: Jeff Layton <jlayton@primarydata.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

diff --git a/fs/nfsd/auth.c b/fs/nfsd/auth.c
index 72f44823adbbaca47890feaf735255646d66674c..9d46a0bdd9f9aea4d882a77ac3c22454d0f2b634 100644 (file)
--- a/fs/nfsd/auth.c
+++ b/fs/nfsd/auth.c
@@ -28,7 +28,7 @@ int nfsd_setuser(struct svc_rqst *rqstp, struct svc_export *exp)
        validate_process_creds();
 
        /* discard any old override before preparing the new set */
-       revert_creds(get_cred(current->real_cred));
+       revert_creds(get_cred(current_real_cred()));
        new = prepare_creds();
        if (!new)
                return -ENOMEM;

diff --git a/include/linux/cred.h b/include/linux/cred.h
index f61d6c8f5ef317579adcc17d873f4694327c2c53..b2d0820837c4259915c42208e696b09bf56c365d 100644 (file)
--- a/include/linux/cred.h
+++ b/include/linux/cred.h
@@ -258,6 +258,15 @@ static inline void put_cred(const struct cred *_cred)
 #define current_cred() \
        rcu_dereference_protected(current->cred, 1)
 
+/**
+ * current_real_cred - Access the current task's objective credentials
+ *
+ * Access the objective credentials of the current task.  RCU-safe,
+ * since nobody else can modify it.
+ */
+#define current_real_cred() \
+       rcu_dereference_protected(current->real_cred, 1)
+
 /**
  * __task_cred - Access a task's objective credentials
  * @task: The task to query