Subject: [PATCH] memblock: Add checking about illegal using memblock.reserved

After memblock is not used anymore, Clear the memblock reserved so we will not
use it wrongly.

Signed-off-by: Yinghai Lu <yinghai@kernel.org>

---
 arch/x86/mm/init_32.c    |    3 +++
 arch/x86/mm/init_64.c    |    2 ++
 include/linux/memblock.h |    1 +
 mm/memblock.c            |   15 +++++++++++++++
 4 files changed, 21 insertions(+)

Index: linux-2.6/arch/x86/mm/init_32.c
===================================================================
--- linux-2.6.orig/arch/x86/mm/init_32.c
+++ linux-2.6/arch/x86/mm/init_32.c
@@ -759,6 +759,9 @@ void __init mem_init(void)
 		if (page_is_ram(tmp) && PageReserved(pfn_to_page(tmp)))
 			reservedpages++;
 
+	/* clear reserved to catch wrong usage */
+	memblock_clear_reserved();
+
 	codesize =  (unsigned long) &_etext - (unsigned long) &_text;
 	datasize =  (unsigned long) &_edata - (unsigned long) &_etext;
 	initsize =  (unsigned long) &__init_end - (unsigned long) &__init_begin;
Index: linux-2.6/arch/x86/mm/init_64.c
===================================================================
--- linux-2.6.orig/arch/x86/mm/init_64.c
+++ linux-2.6/arch/x86/mm/init_64.c
@@ -699,6 +699,8 @@ void __init mem_init(void)
 
 	absent_pages = absent_pages_in_range(0, max_pfn);
 	reservedpages = max_pfn - totalram_pages - absent_pages;
+	/* clear reserved to catch wrong usage */
+	memblock_clear_reserved();
 	after_bootmem = 1;
 
 	codesize =  (unsigned long) &_etext - (unsigned long) &_text;
Index: linux-2.6/include/linux/memblock.h
===================================================================
--- linux-2.6.orig/include/linux/memblock.h
+++ linux-2.6/include/linux/memblock.h
@@ -46,6 +46,7 @@ extern int memblock_debug;
 #define memblock_dbg(fmt, ...) \
 	if (memblock_debug) printk(KERN_INFO pr_fmt(fmt), ##__VA_ARGS__)
 
+void memblock_clear_reserved(void);
 phys_addr_t memblock_find_in_range_node(phys_addr_t start, phys_addr_t end,
 				phys_addr_t size, phys_addr_t align, int nid);
 phys_addr_t memblock_find_in_range(phys_addr_t start, phys_addr_t end,
Index: linux-2.6/mm/memblock.c
===================================================================
--- linux-2.6.orig/mm/memblock.c
+++ linux-2.6/mm/memblock.c
@@ -101,6 +101,8 @@ phys_addr_t __init_memblock memblock_fin
 	phys_addr_t this_start, this_end, cand;
 	u64 i;
 
+	WARN_ONCE(!memblock.reserved.max, "memblock.reserved was cleared already!");
+
 	/* pump up @end */
 	if (end == MEMBLOCK_ALLOC_ACCESSIBLE)
 		end = memblock.current_limit;
@@ -143,6 +145,14 @@ phys_addr_t __init_memblock memblock_fin
 					   MAX_NUMNODES);
 }
 
+/*
+ * Clear memblock.reserved
+ */
+void __init_memblock memblock_clear_reserved(void)
+{
+	memset(&memblock.reserved, 0, sizeof(memblock.reserved));
+}
+
 static void __init_memblock memblock_remove_region(struct memblock_type *type, unsigned long r)
 {
 	type->total_size -= type->regions[r].size;
@@ -535,6 +545,8 @@ int __init_memblock memblock_remove(phys
 
 int __init_memblock memblock_free(phys_addr_t base, phys_addr_t size)
 {
+	WARN_ONCE(!memblock.reserved.max, "memblock.reserved was cleared already!");
+
 	memblock_dbg("   memblock_free: [%#016llx-%#016llx] %pF\n",
 		     (unsigned long long)base,
 		     (unsigned long long)base + size,
@@ -547,6 +559,7 @@ int __init_memblock memblock_reserve(phy
 {
 	struct memblock_type *_rgn = &memblock.reserved;
 
+	WARN_ONCE(!memblock.reserved.max, "memblock.reserved was cleared already!");
 	memblock_dbg("memblock_reserve: [%#016llx-%#016llx] %pF\n",
 		     (unsigned long long)base,
 		     (unsigned long long)base + size,
@@ -587,6 +600,8 @@ void __init_memblock __next_free_mem_ran
 	int mi = *idx & 0xffffffff;
 	int ri = *idx >> 32;
 
+	WARN_ONCE(!rsv->max, "memblock.reserved was cleared already!");
+
 	for ( ; mi < mem->cnt; mi++) {
 		struct memblock_region *m = &mem->regions[mi];
 		phys_addr_t m_start = m->base;