At the moment, powerpc and s390 have their own versions of do_softirq which
include local_bh_disable() and __local_bh_enable() calls.  They end up
calling __do_softirq (in kernel/softirq.c) which also does
local_bh_disable/enable.
Apparently the two levels of disable/enable trigger a warning from some
validation code that Ingo is working on, and he would like to see the outer
level removed.  But to do that, we have to move the account_system_vtime
calls that are currently in the arch do_softirq() implementations for
powerpc and s390 into the generic __do_softirq() (this is a no-op for other
archs because account_system_vtime is defined to be an empty inline
function on all other archs).  This patch does that.
Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
 
        local_irq_save(flags);
 
-       if (local_softirq_pending()) {
-               account_system_vtime(current);
-               local_bh_disable();
+       if (local_softirq_pending())
                do_softirq_onstack();
-               account_system_vtime(current);
-               _local_bh_enable();
-       }
 
        local_irq_restore(flags);
 }
 
 
        local_irq_save(flags);
 
-       account_system_vtime(current);
-
-       local_bh_disable();
-
        if (local_softirq_pending()) {
                /* Get current stack pointer. */
                asm volatile("la %0,0(15)" : "=a" (old));
                        __do_softirq();
        }
 
-       account_system_vtime(current);
-
-       _local_bh_enable();
-
        local_irq_restore(flags);
 }
 
 
        int cpu;
 
        pending = local_softirq_pending();
+       account_system_vtime(current);
+
        __local_bh_disable((unsigned long)__builtin_return_address(0));
        trace_softirq_enter();
 
                wakeup_softirqd();
 
        trace_softirq_exit();
+
+       account_system_vtime(current);
        _local_bh_enable();
 }