cred: add get_cred_rcu()
Sometimes we want to opportunistically get a
ref to a cred in an rcu_read_lock protected section.
get_task_cred() does this, and NFS does as similar thing
with its own credential structures.
To prepare for NFS converting to use 'struct cred' more
uniformly, define get_cred_rcu(), and use it in
get_task_cred().
Signed-off-by: NeilBrown <neilb@suse.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
diff --git a/kernel/cred.c b/kernel/cred.c
index 0b3ac72..ba60162 100644
--- a/kernel/cred.c
+++ b/kernel/cred.c
@@ -195,7 +195,7 @@
do {
cred = __task_cred((task));
BUG_ON(!cred);
- } while (!atomic_inc_not_zero(&((struct cred *)cred)->usage));
+ } while (!get_cred_rcu(cred));
rcu_read_unlock();
return cred;