CRED: Wrap task credential accesses in the RAMFS filesystem

Wrap access to task credentials so that they can be separated more easily from
the task_struct during the introduction of COW creds.

Change most current->(|e|s|fs)[ug]id to current_(|e|s|fs)[ug]id().

Change some task->e?[ug]id to task_e?[ug]id().  In some places it makes more
sense to use RCU directly rather than a convenient wrapper; these will be
addressed by later patches.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jmorris@namei.org>
Acked-by: Serge Hallyn <serue@us.ibm.com>
Signed-off-by: James Morris <jmorris@namei.org>
diff --git a/fs/ramfs/inode.c b/fs/ramfs/inode.c
index f031d1c..a83a351 100644
--- a/fs/ramfs/inode.c
+++ b/fs/ramfs/inode.c
@@ -55,8 +55,8 @@
 
 	if (inode) {
 		inode->i_mode = mode;
-		inode->i_uid = current->fsuid;
-		inode->i_gid = current->fsgid;
+		inode->i_uid = current_fsuid();
+		inode->i_gid = current_fsgid();
 		inode->i_blocks = 0;
 		inode->i_mapping->a_ops = &ramfs_aops;
 		inode->i_mapping->backing_dev_info = &ramfs_backing_dev_info;