[RFC 2/3] rcu: allow functions to declare they need RCU locking

[Johannes Berg <johannes@sipsolutions.net>]

[-- Attachment #1: 012-rcu-requires.patch --]
[-- Type: text/plain, Size: 897 bytes --]

Often enough, subsystems have a lookup function that goes from some
sort of key to an RCU-protected structure. They can then declare the
function as such:

struct mystruct *get_mystruct(...) __requires_rcu;

and sparse will automatically be able to check that the function is
invoked under rcu_read_lock().

Not-yet-signed-off-by: Johannes Berg <johannes@sipsolutions.net>
---
 include/linux/rcupdate.h |    4 ++++
 1 file changed, 4 insertions(+)

--- everything.orig/include/linux/rcupdate.h	2008-04-10 15:36:18.000000000 +0200
+++ everything/include/linux/rcupdate.h	2008-04-10 15:36:43.000000000 +0200
@@ -65,6 +65,10 @@ struct rcu_head {
        (ptr)->next = NULL; (ptr)->func = NULL; \
 } while (0)
 
+
+#define __requires_rcu		__requires(RCU)
+#define __macro_requires_rcu	__macro_requires(RCU)
+
 /**
  * rcu_read_lock - mark the beginning of an RCU read-side critical section.
  *

--