[PATCH] mm: use symbolic names instead of indices for zone initialisation

Arch-independent zone-sizing is using indices instead of symbolic names to
offset within an array related to zones (max_zone_pfns).  The unintended
impact is that ZONE_DMA and ZONE_NORMAL is initialised on powerpc instead
of ZONE_DMA and ZONE_HIGHMEM when CONFIG_HIGHMEM is set.  As a result, the
the machine fails to boot but will boot with CONFIG_HIGHMEM turned off.

The following patch properly initialises the max_zone_pfns[] array and uses
symbolic names instead of indices in each architecture using
arch-independent zone-sizing.  Two users have successfully booted their
powerpcs with it (one an ibook G4).  It has also been boot tested on x86,
x86_64, ppc64 and ia64.  Please merge for 2.6.19-rc2.

Credit to Benjamin Herrenschmidt for identifying the bug and rolling the
first fix.  Additional credit to Johannes Berg and Andreas Schwab for
reporting the problem and testing on powerpc.
Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

arch/i386/kernel/setup.c

@@ -1083,16 +1083,15 @@ static unsigned long __init setup_memory(void)
 
 void __init zone_sizes_init(void)
 {
+	unsigned long max_zone_pfns[MAX_NR_ZONES];
+	memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
+	max_zone_pfns[ZONE_DMA] =
+		virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
+	max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
 #ifdef CONFIG_HIGHMEM
-	unsigned long max_zone_pfns[MAX_NR_ZONES] = {
-			virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT,
-			max_low_pfn,
-			highend_pfn};
+	max_zone_pfns[ZONE_HIGHMEM] = highend_pfn;
 	add_active_range(0, 0, highend_pfn);
 #else
-	unsigned long max_zone_pfns[MAX_NR_ZONES] = {
-			virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT,
-			max_low_pfn};
 	add_active_range(0, 0, max_low_pfn);
 #endif
 

arch/i386/mm/discontig.c

@@ -356,11 +356,12 @@ void __init numa_kva_reserve(void)
 void __init zone_sizes_init(void)
 {
 	int nid;
-	unsigned long max_zone_pfns[MAX_NR_ZONES] = {
-		virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT,
-		max_low_pfn,
-		highend_pfn
-	};
+	unsigned long max_zone_pfns[MAX_NR_ZONES];
+	memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
+	max_zone_pfns[ZONE_DMA] =
+		virt_to_phys((char *)MAX_DMA_ADDRESS) >> PAGE_SHIFT;
+	max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
+	max_zone_pfns[ZONE_HIGHMEM] = highend_pfn;
 
 	/* If SRAT has not registered memory, register it now */
 	if (find_max_pfn_with_active_regions() == 0) {

arch/ia64/mm/contig.c

@@ -233,6 +233,7 @@ paging_init (void)
 	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));
 	max_zone_pfns[ZONE_DMA] = max_dma;
 	max_zone_pfns[ZONE_NORMAL] = max_low_pfn;
 

arch/ia64/mm/discontig.c

@@ -709,6 +709,7 @@ void __init paging_init(void)
 			max_pfn = mem_data[node].max_pfn;
 	}
 
+	memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
 	max_zone_pfns[ZONE_DMA] = max_dma;
 	max_zone_pfns[ZONE_NORMAL] = max_pfn;
 	free_area_init_nodes(max_zone_pfns);

arch/powerpc/mm/mem.c

@@ -307,11 +307,12 @@ void __init paging_init(void)
 	       top_of_ram, total_ram);
 	printk(KERN_DEBUG "Memory hole size: %ldMB\n",
 	       (top_of_ram - total_ram) >> 20);
+	memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
 #ifdef CONFIG_HIGHMEM
-	max_zone_pfns[0] = total_lowmem >> PAGE_SHIFT;
-	max_zone_pfns[1] = top_of_ram >> PAGE_SHIFT;
+	max_zone_pfns[ZONE_DMA] = total_lowmem >> PAGE_SHIFT;
+	max_zone_pfns[ZONE_HIGHMEM] = top_of_ram >> PAGE_SHIFT;
 #else
-	max_zone_pfns[0] = top_of_ram >> PAGE_SHIFT;
+	max_zone_pfns[ZONE_DMA] = top_of_ram >> PAGE_SHIFT;
 #endif
 	free_area_init_nodes(max_zone_pfns);
 }

arch/powerpc/mm/numa.c

@@ -617,9 +617,9 @@ void __init do_init_bootmem(void)
 
 void __init paging_init(void)
 {
-	unsigned long max_zone_pfns[MAX_NR_ZONES] = {
-				lmb_end_of_DRAM() >> PAGE_SHIFT
-	};
+	unsigned long max_zone_pfns[MAX_NR_ZONES];
+	memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
+	max_zone_pfns[ZONE_DMA] = lmb_end_of_DRAM() >> PAGE_SHIFT;
 	free_area_init_nodes(max_zone_pfns);
 }
 

arch/ppc/mm/init.c

@@ -374,11 +374,12 @@ void __init paging_init(void)
 	end_pfn = start_pfn + (total_memory >> PAGE_SHIFT);
 	add_active_range(0, start_pfn, end_pfn);
 
+	memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
 #ifdef CONFIG_HIGHMEM
-	max_zone_pfns[0] = total_lowmem >> PAGE_SHIFT;
-	max_zone_pfns[1] = total_memory >> PAGE_SHIFT;
+	max_zone_pfns[ZONE_DMA] = total_lowmem >> PAGE_SHIFT;
+	max_zone_pfns[ZONE_HIGHMEM] = total_memory >> PAGE_SHIFT;
 #else
-	max_zone_pfns[0] = total_memory >> PAGE_SHIFT;
+	max_zone_pfns[ZONE_DMA] = total_memory >> PAGE_SHIFT;
 #endif /* CONFIG_HIGHMEM */
 	free_area_init_nodes(max_zone_pfns);
 }

arch/x86_64/mm/init.c

@@ -406,9 +406,12 @@ void __cpuinit zap_low_mappings(int cpu)
 #ifndef CONFIG_NUMA
 void __init paging_init(void)
 {
-	unsigned long max_zone_pfns[MAX_NR_ZONES] = {MAX_DMA_PFN,
-							MAX_DMA32_PFN,
-							end_pfn};
+	unsigned long max_zone_pfns[MAX_NR_ZONES];
+	memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
+	max_zone_pfns[ZONE_DMA] = MAX_DMA_PFN;
+	max_zone_pfns[ZONE_DMA32] = MAX_DMA32_PFN;
+	max_zone_pfns[ZONE_NORMAL] = end_pfn;
+
 	memory_present(0, 0, end_pfn);
 	sparse_init();
 	free_area_init_nodes(max_zone_pfns);

arch/x86_64/mm/numa.c

@@ -338,9 +338,11 @@ static void __init arch_sparse_init(void)
 void __init paging_init(void)
 { 
 	int i;
-	unsigned long max_zone_pfns[MAX_NR_ZONES] = { MAX_DMA_PFN,
-		MAX_DMA32_PFN,
-		end_pfn};
+	unsigned long max_zone_pfns[MAX_NR_ZONES];
+	memset(max_zone_pfns, 0, sizeof(max_zone_pfns));
+	max_zone_pfns[ZONE_DMA] = MAX_DMA_PFN;
+	max_zone_pfns[ZONE_DMA32] = MAX_DMA32_PFN;
+	max_zone_pfns[ZONE_NORMAL] = end_pfn;
 
 	arch_sparse_init();