memblock: Make MEMBLOCK_ERROR be 0
And ensure we don't hand out 0 as a valid allocation. We put the
low limit at PAGE_SIZE arbitrarily.
Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
diff --git a/include/linux/memblock.h b/include/linux/memblock.h
index 1a9c29c..dfa6449 100644
--- a/include/linux/memblock.h
+++ b/include/linux/memblock.h
@@ -19,7 +19,7 @@
#include <asm/memblock.h>
#define INIT_MEMBLOCK_REGIONS 128
-#define MEMBLOCK_ERROR (~(phys_addr_t)0)
+#define MEMBLOCK_ERROR 0
struct memblock_region {
phys_addr_t base;
diff --git a/mm/memblock.c b/mm/memblock.c
index 85cfa1d..cb520df 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -105,6 +105,12 @@
phys_addr_t base, res_base;
long j;
+ /* Prevent allocations returning 0 as it's also used to
+ * indicate an allocation failure
+ */
+ if (start == 0)
+ start = PAGE_SIZE;
+
base = memblock_align_down((end - size), align);
while (start <= base) {
j = memblock_overlaps_region(&memblock.reserved, base, size);