[patch 03/18] smp: Add generic smpboot facility

From: Thomas Gleixner
Date: Fri Apr 20 2012 - 09:07:48 EST


Start a new file, which will hold SMP and CPU hotplug related generic
infrastructure.

Signed-off-by: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Matt Turner <mattst88@xxxxxxxxx>
Cc: Russell King <linux@xxxxxxxxxxxxxxxx>
Cc: Mike Frysinger <vapier@xxxxxxxxxx>
Cc: Jesper Nilsson <jesper.nilsson@xxxxxxxx>
Cc: Richard Kuo <rkuo@xxxxxxxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Cc: Hirokazu Takata <takata@xxxxxxxxxxxxxx>
Cc: Ralf Baechle <ralf@xxxxxxxxxxxxxx>
Cc: David Howells <dhowells@xxxxxxxxxx>
Cc: "James E.J. Bottomley" <jejb@xxxxxxxxxxxxxxxx>
Cc: Benjamin Herrenschmidt <benh@xxxxxxxxxxxxxxxxxxx>
Cc: Martin Schwidefsky <schwidefsky@xxxxxxxxxx>
Cc: Paul Mundt <lethal@xxxxxxxxxxxx>
Cc: "David S. Miller" <davem@xxxxxxxxxxxxx>
Cc: Chris Metcalf <cmetcalf@xxxxxxxxxx>
Cc: Richard Weinberger <richard@xxxxxx>
Cc: x86@xxxxxxxxxx
---
kernel/Makefile | 1 +
kernel/cpu.c | 8 ++++++++
kernel/smpboot.c | 12 ++++++++++++
kernel/smpboot.h | 6 ++++++
4 files changed, 27 insertions(+)

Index: linux-2.6/kernel/Makefile
===================================================================
--- linux-2.6.orig/kernel/Makefile
+++ linux-2.6/kernel/Makefile
@@ -43,6 +43,7 @@ obj-$(CONFIG_DEBUG_RT_MUTEXES) += rtmute
obj-$(CONFIG_RT_MUTEX_TESTER) += rtmutex-tester.o
obj-$(CONFIG_GENERIC_ISA_DMA) += dma.o
obj-$(CONFIG_SMP) += smp.o
+obj-$(CONFIG_SMP) += smpboot.o
ifneq ($(CONFIG_SMP),y)
obj-y += up.o
endif
Index: linux-2.6/kernel/cpu.c
===================================================================
--- linux-2.6.orig/kernel/cpu.c
+++ linux-2.6/kernel/cpu.c
@@ -17,6 +17,8 @@
#include <linux/gfp.h>
#include <linux/suspend.h>

+#include "smpboot.h"
+
#ifdef CONFIG_SMP
/* Serializes the updates to cpu_online_mask, cpu_present_mask */
static DEFINE_MUTEX(cpu_add_remove_lock);
@@ -300,6 +302,11 @@ static int __cpuinit _cpu_up(unsigned in
return -EINVAL;

cpu_hotplug_begin();
+
+ ret = smpboot_prepare(cpu);
+ if (ret)
+ goto out;
+
ret = __cpu_notify(CPU_UP_PREPARE | mod, hcpu, -1, &nr_calls);
if (ret) {
nr_calls--;
@@ -320,6 +327,7 @@ static int __cpuinit _cpu_up(unsigned in
out_notify:
if (ret != 0)
__cpu_notify(CPU_UP_CANCELED | mod, hcpu, nr_calls, NULL);
+out:
cpu_hotplug_done();

return ret;
Index: linux-2.6/kernel/smpboot.c
===================================================================
--- /dev/null
+++ linux-2.6/kernel/smpboot.c
@@ -0,0 +1,12 @@
+/*
+ * Common SMP CPU bringup/teardown functions
+ */
+
+#include "smpboot.h"
+
+/**
+ * smpboot_prepare - generic smpboot preparation
+ */
+int __cpuinit smpboot_prepare(unsigned int cpu)
+{
+}
Index: linux-2.6/kernel/smpboot.h
===================================================================
--- /dev/null
+++ linux-2.6/kernel/smpboot.h
@@ -0,0 +1,6 @@
+#ifndef SMPBOOT_H
+#define SMPBOOT_H
+
+int smpboot_prepare(unsigned int cpu);
+
+#endif


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