powerpc: Avoid extra indirect function call in sending IPIs

On many platforms (including pSeries), smp_ops->message_pass is always
smp_muxed_ipi_message_pass.  This changes arch/powerpc/kernel/smp.c so
that if smp_ops->message_pass is NULL, it calls smp_muxed_ipi_message_pass
directly.

This means that a platform doesn't need to set both .message_pass and
.cause_ipi, only one of them.  It is a slight performance improvement
in that it gets rid of an indirect function call at the expense of a
predictable conditional branch.

Signed-off-by: Paul Mackerras <paulus@samba.org>
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>

1 files changed, 1 insertions, 1 deletions

diff --git a/arch/powerpc/platforms/pseries/smp.c b/arch/powerpc/platforms/pseries/smp.c
index fbffd7e47ab..84dafd33edc 100644
--- a/arch/powerpc/platforms/pseries/smp.c
+++ b/arch/powerpc/platforms/pseries/smp.c
@@ -207,7 +207,7 @@ static struct smp_ops_t pSeries_mpic_smp_ops = {
 };
 
 static struct smp_ops_t pSeries_xics_smp_ops = {
-        .message_pass   = smp_muxed_ipi_message_pass,
+        .message_pass   = NULL, /* Use smp_muxed_ipi_message_pass */
         .cause_ipi      = NULL, /* Filled at runtime by xics_smp_probe() */
         .probe          = xics_smp_probe,
         .kick_cpu       = smp_pSeries_kick_cpu,