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>

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>
Benjamin Herrenschmidt
1 parent 37d8d4bf48
Showing 2 changed files with 7 additions and 1 deletions Side-by-side Diff
include/linux/memblock.h
mm/memblock.c
@@ -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;
@@ -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);
...	...	@@ -19,7 +19,7 @@
19	19	#include <asm/memblock.h>
20	20
21	21	#define INIT_MEMBLOCK_REGIONS 128
22		-#define MEMBLOCK_ERROR (~(phys_addr_t)0)
	22	+#define MEMBLOCK_ERROR 0
23	23
24	24	struct memblock_region {
25	25	phys_addr_t base;
...	...	@@ -105,6 +105,12 @@
105	105	phys_addr_t base, res_base;
106	106	long j;
107	107
	108	+ /* Prevent allocations returning 0 as it's also used to
	109	+ * indicate an allocation failure
	110	+ */
	111	+ if (start == 0)
	112	+ start = PAGE_SIZE;
	113	+
108	114	base = memblock_align_down((end - size), align);
109	115	while (start <= base) {
110	116	j = memblock_overlaps_region(&memblock.reserved, base, size);