keys: sparse: Fix key_fs[ug]id_changed()

Sparse warnings are incurred by key_fs[ug]id_changed() due to unprotected
accesses of tsk->cred, which is marked __rcu.

Fix this by passing the new cred struct to these functions from
commit_creds() rather than the task pointer.

Signed-off-by: David Howells <dhowells@redhat.com>
Reviewed-by: James Morris <jamorris@linux.microsoft.com>
diff --git a/include/linux/key.h b/include/linux/key.h
index 7099985..1f09aad 100644
--- a/include/linux/key.h
+++ b/include/linux/key.h
@@ -402,8 +402,8 @@ extern struct ctl_table key_sysctls[];
  * the userspace interface
  */
 extern int install_thread_keyring_to_cred(struct cred *cred);
-extern void key_fsuid_changed(struct task_struct *tsk);
-extern void key_fsgid_changed(struct task_struct *tsk);
+extern void key_fsuid_changed(struct cred *new_cred);
+extern void key_fsgid_changed(struct cred *new_cred);
 extern void key_init(void);
 
 #else /* CONFIG_KEYS */
@@ -418,8 +418,8 @@ extern void key_init(void);
 #define make_key_ref(k, p)		NULL
 #define key_ref_to_ptr(k)		NULL
 #define is_key_possessed(k)		0
-#define key_fsuid_changed(t)		do { } while(0)
-#define key_fsgid_changed(t)		do { } while(0)
+#define key_fsuid_changed(c)		do { } while(0)
+#define key_fsgid_changed(c)		do { } while(0)
 #define key_init()			do { } while(0)
 
 #endif /* CONFIG_KEYS */