[IA64] cleanup contig/discontig/virt_mem_map macros

I got this patch from Zou Nan hai to resolve the problem that
Andrew Morton has been having booting his ia64 system.  The code
is quite a bit cleaner as he has reduced the number of different
definitions of pfn_valid/page_to_pfn/pfn_to_page, and left the
only remaining ones next to each other in page.h ... so this
should be easier to maintain going forward.
Signed-off-by: Tony Luck <tony.luck@intel.com>

arch/ia64/mm/contig.c

@@ -269,7 +269,6 @@ paging_init (void)
 		vmem_map = (struct page *) 0;
 		free_area_init_node(0, &contig_page_data, zones_size, 0,
 				    zholes_size);
-		mem_map = contig_page_data.node_mem_map;
 	} else {
 		unsigned long map_size;
 
@@ -280,11 +279,10 @@ paging_init (void)
 		vmem_map = (struct page *) vmalloc_end;
 		efi_memmap_walk(create_mem_map_page_table, 0);
 
-		contig_page_data.node_mem_map = vmem_map;
+		mem_map = contig_page_data.node_mem_map = vmem_map;
 		free_area_init_node(0, &contig_page_data, zones_size,
 				    0, zholes_size);
 
-		mem_map = contig_page_data.node_mem_map;
 		printk("Virtual mem_map starts at 0x%p\n", mem_map);
 	}
 #else /* !CONFIG_VIRTUAL_MEM_MAP */

include/asm-ia64/mmzone.h

@@ -27,12 +27,6 @@
 # define NR_NODE_MEMBLKS	(NR_NODES * 4)
 #endif
 
-extern unsigned long max_low_pfn;
-
-#define pfn_valid(pfn)		(((pfn) < max_low_pfn) && ia64_pfn_valid(pfn))
-#define page_to_pfn(page)	((unsigned long) (page - vmem_map))
-#define pfn_to_page(pfn)	(vmem_map + (pfn))
-
 #else /* CONFIG_DISCONTIGMEM */
 # define NR_NODE_MEMBLKS	4
 #endif /* CONFIG_DISCONTIGMEM */

include/asm-ia64/page.h

@@ -84,17 +84,16 @@ extern int ia64_pfn_valid (unsigned long pfn);
 #endif
 
 #ifndef CONFIG_DISCONTIGMEM
-# ifdef CONFIG_VIRTUAL_MEM_MAP
-extern struct page *vmem_map;
-#  define pfn_valid(pfn)	(((pfn) < max_mapnr) && ia64_pfn_valid(pfn))
-#  define page_to_pfn(page)	((unsigned long) (page - vmem_map))
-#  define pfn_to_page(pfn)	(vmem_map + (pfn))
-# else
 # define pfn_valid(pfn)		(((pfn) < max_mapnr) && ia64_pfn_valid(pfn))
 # define page_to_pfn(page)	((unsigned long) (page - mem_map))
 # define pfn_to_page(pfn)	(mem_map + (pfn))
-# endif
-#endif /* CONFIG_DISCONTIGMEM */
+#else
+extern struct page *vmem_map;
+extern unsigned long max_low_pfn;
+# define pfn_valid(pfn)		(((pfn) < max_low_pfn) && ia64_pfn_valid(pfn))
+# define page_to_pfn(page)	((unsigned long) (page - vmem_map))
+# define pfn_to_page(pfn)	(vmem_map + (pfn))
+#endif
 
 #define page_to_phys(page)	(page_to_pfn(page) << PAGE_SHIFT)
 #define virt_to_page(kaddr)	pfn_to_page(__pa(kaddr) >> PAGE_SHIFT)