From 236260b90dd94516982ad67aa6f5449c4c37db7b Mon Sep 17 00:00:00 2001
From: Jeremy Fitzhardinge <jeremy@goop.org>
Date: Wed, 6 Oct 2010 15:52:29 -0700
Subject: [PATCH] memblock: Allow memblock_init to be called early

The Xen setup code needs to call memblock_x86_reserve_range() very early,
so allow it to initialize the memblock subsystem before doing so.  The
second memblock_init() is ignored.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Cc: Yinghai Lu <yinghai@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
LKML-Reference: <4CACFDAD.3090900@goop.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
---
 arch/x86/xen/enlighten.c | 3 +++
 mm/memblock.c            | 6 ++++++
 2 files changed, 9 insertions(+)

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 7d46c8441418..63b83ceebd1a 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -30,6 +30,7 @@
 #include <linux/console.h>
 #include <linux/pci.h>
 #include <linux/gfp.h>
+#include <linux/memblock.h>
 
 #include <xen/xen.h>
 #include <xen/interface/xen.h>
@@ -1183,6 +1184,8 @@ asmlinkage void __init xen_start_kernel(void)
 	local_irq_disable();
 	early_boot_irqs_off();
 
+	memblock_init();
+
 	xen_raw_console_write("mapping kernel into physical memory\n");
 	pgd = xen_setup_kernel_pagetable(pgd, xen_start_info->nr_pages);
 
diff --git a/mm/memblock.c b/mm/memblock.c
index 9ad39690a2bd..ae8b06c828c7 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -752,6 +752,12 @@ void __init memblock_analyze(void)
 
 void __init memblock_init(void)
 {
+	static int init_done __initdata = 0;
+
+	if (init_done)
+		return;
+	init_done = 1;
+
 	/* Hookup the initial arrays */
 	memblock.memory.regions	= memblock_memory_init_regions;
 	memblock.memory.max		= INIT_MEMBLOCK_REGIONS;
-- 
2.34.1