Revert "x86_64: allocate sparsemem memmap above 4G"

This reverts commit 2e1c49db.

First off, testing in Fedora has shown it to cause boot failures,
bisected down by Martin Ebourne, and reported by Dave Jobes.  So the
commit will likely be reverted in the 2.6.23 stable kernels.

Secondly, in the 2.6.24 model, x86-64 has now grown support for
SPARSEMEM_VMEMMAP, which disables the relevant code anyway, so while the
bug is not visible any more, it's become invisible due to the code just
being irrelevant and no longer enabled on the only architecture that
this ever affected.
Reported-by: Dave Jones <davej@redhat.com>
Tested-by: Martin Ebourne <fedora@ebourne.me.uk>
Cc: Zou Nan hai <nanhai.zou@intel.com>
Cc: Suresh Siddha <suresh.b.siddha@intel.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Acked-by: Andy Whitcroft <apw@shadowen.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/x86/mm/init_64.c

@@ -728,12 +728,6 @@ int in_gate_area_no_task(unsigned long addr)
 	return (addr >= VSYSCALL_START) && (addr < VSYSCALL_END);
 }
 
-void * __init alloc_bootmem_high_node(pg_data_t *pgdat, unsigned long size)
-{
-	return __alloc_bootmem_core(pgdat->bdata, size,
-			SMP_CACHE_BYTES, (4UL*1024*1024*1024), 0);
-}
-
 const char *arch_vma_name(struct vm_area_struct *vma)
 {
 	if (vma->vm_mm && vma->vm_start == (long)vma->vm_mm->context.vdso)

include/linux/bootmem.h

@@ -59,7 +59,6 @@ extern void *__alloc_bootmem_core(struct bootmem_data *bdata,
 				  unsigned long align,
 				  unsigned long goal,
 				  unsigned long limit);
-extern void *alloc_bootmem_high_node(pg_data_t *pgdat, unsigned long size);
 
 #ifndef CONFIG_HAVE_ARCH_BOOTMEM_NODE
 extern void reserve_bootmem(unsigned long addr, unsigned long size);

mm/sparse.c

@@ -220,12 +220,6 @@ static int __meminit sparse_init_one_section(struct mem_section *ms,
 	return 1;
 }
 
-__attribute__((weak)) __init
-void *alloc_bootmem_high_node(pg_data_t *pgdat, unsigned long size)
-{
-	return NULL;
-}
-
 static unsigned long usemap_size(void)
 {
 	unsigned long size_bytes;
@@ -267,11 +261,6 @@ struct page __init *sparse_mem_map_populate(unsigned long pnum, int nid)
 	if (map)
 		return map;
 
-  	map = alloc_bootmem_high_node(NODE_DATA(nid),
-                       sizeof(struct page) * PAGES_PER_SECTION);
-	if (map)
-		return map;
-
 	map = alloc_bootmem_node(NODE_DATA(nid),
 			sizeof(struct page) * PAGES_PER_SECTION);
 	return map;