tree c07d32656adeb46ad5deee4e6e4e65e9b0177177
parent 3c969095a3ccb15ae1b654f33b3cd5e4ff3c622f
author Oleg Nesterov <oleg@redhat.com> 1440528318 +0200
committer Paul E. McKenney <paulmck@linux.vnet.ibm.com> 1440534546 -0700

rcu: Change _wait_rcu_gp() to work around gcc 67055 bug

Code like this in inline functions can confuse 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/rcusync.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@redhat.com>
Reported-by: Guenter Roeck <linux@roeck-us.net>
Signed-off-by: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>