[PATCH] optional ZONE_DMA: optional ZONE_DMA for ia64

ZONE_DMA less operation for IA64 SGI platform

Disable ZONE_DMA for SGI SN2.  All memory is addressable by all devices and we
do not need any special memory pool.
Signed-off-by: Christoph Lameter <clameter@sgi.com>
Cc: "Luck, Tony" <tony.luck@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

arch/ia64/Kconfig

@@ -25,8 +25,8 @@ config 64BIT
 	default y
 
 config ZONE_DMA
-	bool
-	default y
+	def_bool y
+	depends on !IA64_SGI_SN2
 
 config MMU
 	bool

arch/ia64/mm/contig.c

@@ -259,9 +259,11 @@ paging_init (void)
 	num_physpages = 0;
 	efi_memmap_walk(count_pages, &num_physpages);
 
-	max_dma = virt_to_phys((void *) MAX_DMA_ADDRESS) >> PAGE_SHIFT;
 	memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
+#ifdef CONFIG_ZONE_DMA
+	max_dma = virt_to_phys((void *) MAX_DMA_ADDRESS) >> PAGE_SHIFT;
 	max_zone_pfns[ZONE_DMA] = max_dma;
+#endif
 	max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
 
 #ifdef CONFIG_VIRTUAL_MEM_MAP

arch/ia64/mm/discontig.c

@@ -37,7 +37,9 @@ struct early_node_data {
 	unsigned long pernode_size;
 	struct bootmem_data bootmem_data;
 	unsigned long num_physpages;
+#ifdef CONFIG_ZONE_DMA
 	unsigned long num_dma_physpages;
+#endif
 	unsigned long min_pfn;
 	unsigned long max_pfn;
 };
@@ -633,9 +635,11 @@ static __init int count_node_pages(unsigned long start, unsigned long len, int n
 	unsigned long end = start + len;
 
 	mem_data[node].num_physpages += len >> PAGE_SHIFT;
+#ifdef CONFIG_ZONE_DMA
 	if (start <= __pa(MAX_DMA_ADDRESS))
 		mem_data[node].num_dma_physpages +=
 			(min(end, __pa(MAX_DMA_ADDRESS)) - start) >>PAGE_SHIFT;
+#endif
 	start = GRANULEROUNDDOWN(start);
 	start = ORDERROUNDDOWN(start);
 	end = GRANULEROUNDUP(end);
@@ -688,7 +692,9 @@ void __init paging_init(void)
 	}
 
 	memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
+#ifdef CONFIG_ZONE_DMA
 	max_zone_pfns[ZONE_DMA] = max_dma;
+#endif
 	max_zone_pfns[ZONE_NORMAL] = max_pfn;
 	free_area_init_nodes(max_zone_pfns);