[PATCH tip/core/rcu 1/3] rcu: avoid build error for third-party modules

From: Paul E. McKenney
Date: Wed May 11 2011 - 17:00:18 EST


The initial definition of __kfree_rcu() checked a static inline function
argument to see if it was a compile-time constant. Apparently not all
compilers are willing to put up with this at all optimization levels.
Add a nasty comment and remove the warning, relying on the fact that
__kfree_rcu() is called only from kfree_rcu(), which always passes in
a compile-time constant.

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
include/linux/rcupdate.h | 5 +++--
1 files changed, 3 insertions(+), 2 deletions(-)

diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index 99f9aa7..58b13f1 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -814,13 +814,14 @@ static __always_inline bool __is_kfree_rcu_offset(unsigned long offset)
return offset < 4096;
}

+/*
+ * Intended to be called only from the kfree_rcu() macro.
+ */
static __always_inline
void __kfree_rcu(struct rcu_head *head, unsigned long offset)
{
typedef void (*rcu_callback)(struct rcu_head *);

- BUILD_BUG_ON(!__builtin_constant_p(offset));
-
/* See the kfree_rcu() header comment. */
BUILD_BUG_ON(!__is_kfree_rcu_offset(offset));

--
1.7.3.2

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