s390/irq: select HAVE_IRQ_EXIT_ON_IRQ_STACK
irq_exit() is always called on async stack. Therefore select
HAVE_IRQ_EXIT_ON_IRQ_STACK and get a tiny optimization in
invoke_softirq().
Signed-off-by: Heiko Carstens <hca@linux.ibm.com>
diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index a60cc52..9e8895c 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -153,6 +153,7 @@
select HAVE_FUTEX_CMPXCHG if FUTEX
select HAVE_GCC_PLUGINS
select HAVE_GENERIC_VDSO
+ select HAVE_IRQ_EXIT_ON_IRQ_STACK
select HAVE_KERNEL_BZIP2
select HAVE_KERNEL_GZIP
select HAVE_KERNEL_LZ4