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>

5 files changed, 5 insertions, 5 deletions

diff --git a/arch/powerpc/platforms/85xx/smp.c b/arch/powerpc/platforms/85xx/smp.c
index d6a93a10c0f5..8eef8d2b4472 100644
--- a/arch/powerpc/platforms/85xx/smp.c
+++ b/arch/powerpc/platforms/85xx/smp.c
@@ -236,7 +236,7 @@ void __init mpc85xx_smp_init(void)
         }
 
         if (cpu_has_feature(CPU_FTR_DBELL)) {
-                smp_85xx_ops.message_pass = smp_muxed_ipi_message_pass;
+                /* .message_pass defaults to smp_muxed_ipi_message_pass */
                 smp_85xx_ops.cause_ipi = doorbell_cause_ipi;
         }
 
diff --git a/arch/powerpc/platforms/iseries/smp.c b/arch/powerpc/platforms/iseries/smp.c
index e3265adde5d3..2df48c2287bd 100644
--- a/arch/powerpc/platforms/iseries/smp.c
+++ b/arch/powerpc/platforms/iseries/smp.c
@@ -75,7 +75,7 @@ static void __devinit smp_iSeries_setup_cpu(int nr)
 }
 
 static struct smp_ops_t iSeries_smp_ops = {
-        .message_pass = smp_muxed_ipi_message_pass,
+        .message_pass = NULL,   /* Use smp_muxed_ipi_message_pass */
         .cause_ipi    = smp_iSeries_cause_ipi,
         .probe        = smp_iSeries_probe,
         .kick_cpu     = smp_iSeries_kick_cpu,
diff --git a/arch/powerpc/platforms/powermac/smp.c b/arch/powerpc/platforms/powermac/smp.c
index db092d7c4c5b..d15fca322978 100644
--- a/arch/powerpc/platforms/powermac/smp.c
+++ b/arch/powerpc/platforms/powermac/smp.c
@@ -447,7 +447,7 @@ void __init smp_psurge_give_timebase(void)
 
 /* PowerSurge-style Macs */
 struct smp_ops_t psurge_smp_ops = {
-        .message_pass   = smp_muxed_ipi_message_pass,
+        .message_pass   = NULL, /* Use smp_muxed_ipi_message_pass */
         .cause_ipi      = smp_psurge_cause_ipi,
         .probe          = smp_psurge_probe,
         .kick_cpu       = smp_psurge_kick_cpu,
diff --git a/arch/powerpc/platforms/pseries/smp.c b/arch/powerpc/platforms/pseries/smp.c
index fbffd7e47ab8..84dafd33edc5 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,
diff --git a/arch/powerpc/platforms/wsp/smp.c b/arch/powerpc/platforms/wsp/smp.c
index 9d20fa9d3710..71bd105f3863 100644
--- a/arch/powerpc/platforms/wsp/smp.c
+++ b/arch/powerpc/platforms/wsp/smp.c
@@ -75,7 +75,7 @@ static int __init smp_a2_probe(void)
 }
 
 static struct smp_ops_t a2_smp_ops = {
-        .message_pass   = smp_muxed_ipi_message_pass,
+        .message_pass   = NULL, /* Use smp_muxed_ipi_message_pass */
         .cause_ipi      = doorbell_cause_ipi,
         .probe          = smp_a2_probe,
         .kick_cpu       = smp_a2_kick_cpu,