[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>

9 files changed, 36 insertions, 27 deletions

diff --git a/arch/i386/kernel/setup.c b/arch/i386/kernel/setup.c
index 000cf03751fe..519e63c3c130 100644
--- a/arch/i386/kernel/setup.c
+++ b/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
 
diff --git a/arch/i386/mm/discontig.c b/arch/i386/mm/discontig.c
index 455597db84df..ddbdb0336f28 100644
--- a/arch/i386/mm/discontig.c
+++ b/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) {
diff --git a/arch/ia64/mm/contig.c b/arch/ia64/mm/contig.c
index daf977ff2920..82deaa3a7c48 100644
--- a/arch/ia64/mm/contig.c
+++ b/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;
 
diff --git a/arch/ia64/mm/discontig.c b/arch/ia64/mm/discontig.c
index d497b6b0f5b2..96722cb1b49d 100644
--- a/arch/ia64/mm/discontig.c
+++ b/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);
diff --git a/arch/powerpc/mm/mem.c b/arch/powerpc/mm/mem.c
index 16fe027bbc12..d1c0758c5611 100644
--- a/arch/powerpc/mm/mem.c
+++ b/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);
 }
diff --git a/arch/powerpc/mm/numa.c b/arch/powerpc/mm/numa.c
index 43c272075e1a..9da01dc8cfd9 100644
--- a/arch/powerpc/mm/numa.c
+++ b/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);
 }
 
diff --git a/arch/ppc/mm/init.c b/arch/ppc/mm/init.c
index 410200046af1..c374e53ae03a 100644
--- a/arch/ppc/mm/init.c
+++ b/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);
 }
diff --git a/arch/x86_64/mm/init.c b/arch/x86_64/mm/init.c
index 19c72520a868..971dc1181e69 100644
--- a/arch/x86_64/mm/init.c
+++ b/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);
diff --git a/arch/x86_64/mm/numa.c b/arch/x86_64/mm/numa.c
index 829a008bd39b..2ee2e003606c 100644
--- a/arch/x86_64/mm/numa.c
+++ b/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();