Commit-ID: 66e8c57da6bf6b847a48a5a6fda59512f733ed78
Gitweb: http://git.kernel.org/tip/66e8c57da6bf6b847a48a5a6fda59512f733ed78
Author: Oleg Nesterov <oleg@xxxxxxxxxx>
AuthorDate: Tue, 25 Aug 2015 20:45:18 +0200
Committer: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
CommitDate: Sun, 20 Sep 2015 20:50:06 -0700
rcu: Change _wait_rcu_gp() to work around GCC bug 67055
Code like this in inline functions confuses some recent versions of gcc:
const int n = const-expr;
whatever_t array[n];
For more details, see:
https://gcc.gnu.org/bugzilla/show_bug.cgi?id=67055#c13
This compiler bug results in the following failure after 114b7fd4b (rcu:
Create rcu_sync infrastructure):
In file included from include/linux/rcupdate.h:429:0,
from include/linux/rcu_sync.h:5,
from kernel/rcu/sync.c:1:
include/linux/rcutiny.h: In function 'rcu_barrier_sched':
include/linux/rcutiny.h:55:20: internal compiler error: Segmentation fault
static inline void rcu_barrier_sched(void)
This commit therefore eliminates the constant local variable in favor of
direct use of the expression.
Reported-and-tested-by: Mark Salter <msalter@xxxxxxxxxx>
Reported-by: Guenter Roeck <linux@xxxxxxxxxxxx>
Signed-off-by: Oleg Nesterov <oleg@xxxxxxxxxx>
Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
include/linux/rcupdate.h | 11 +++++------
1 file changed, 5 insertions(+), 6 deletions(-)
diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h
index ff47651..581abf8 100644
--- a/include/linux/rcupdate.h
+++ b/include/linux/rcupdate.h
@@ -230,12 +230,11 @@ void __wait_rcu_gp(bool checktiny, int n, call_rcu_func_t *crcu_array,
struct rcu_synchronize *rs_array);
#define _wait_rcu_gp(checktiny, ...) \
-do { \
- call_rcu_func_t __crcu_array[] = { __VA_ARGS__ }; \
- const int __n = ARRAY_SIZE(__crcu_array); \
- struct rcu_synchronize __rs_array[__n]; \
- \
- __wait_rcu_gp(checktiny, __n, __crcu_array, __rs_array); \
+do { \
+ call_rcu_func_t __crcu_array[] = { __VA_ARGS__ }; \
+ struct rcu_synchronize __rs_array[ARRAY_SIZE(__crcu_array)]; \
+ __wait_rcu_gp(checktiny, ARRAY_SIZE(__crcu_array), \
+ __crcu_array, __rs_array); \
} while (0)
#define wait_rcu_gp(...) _wait_rcu_gp(false, __VA_ARGS__)
--
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