memblock: free allocated memblock_reserved_regions later

memblock_free_reserved_regions() calls memblock_free(), but
memblock_free() would double reserved.regions too, so we could free the
old range for reserved.regions.

Also tj said there is another bug which could be related to this.

| I don't think we're saving any noticeable
| amount by doing this "free - give it to page allocator - reserve
| again" dancing.  We should just allocate regions aligned to page
| boundaries and free them later when memblock is no longer in use.

in that case, when DEBUG_PAGEALLOC, will get panic:

     memblock_free: [0x0000102febc080-0x0000102febf080] memblock_free_reserved_regions+0x37/0x39
  BUG: unable to handle kernel paging request at ffff88102febd948
  IP: [<ffffffff836a5774>] __next_free_mem_range+0x9b/0x155
  PGD 4826063 PUD cf67a067 PMD cf7fa067 PTE 800000102febd160
  Oops: 0000 [#1] PREEMPT SMP DEBUG_PAGEALLOC
  CPU 0
  Pid: 0, comm: swapper Not tainted 3.5.0-rc2-next-20120614-sasha #447
  RIP: 0010:[<ffffffff836a5774>]  [<ffffffff836a5774>] __next_free_mem_range+0x9b/0x155

See the discussion at https://lkml.org/lkml/2012/6/13/469

So try to allocate with PAGE_SIZE alignment and free it later.

Reported-by: Sasha Levin <levinsasha928@gmail.com>
Acked-by: Tejun Heo <tj@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 23 insertions, 28 deletions

diff --git a/mm/memblock.c b/mm/memblock.c
index d4382095f8b..5cc6731b00c 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -143,30 +143,6 @@ phys_addr_t __init_memblock memblock_find_in_range(phys_addr_t start,
 					   MAX_NUMNODES);
 }
 
-/*
- * Free memblock.reserved.regions
- */
-int __init_memblock memblock_free_reserved_regions(void)
-{
-	if (memblock.reserved.regions == memblock_reserved_init_regions)
-		return 0;
-
-	return memblock_free(__pa(memblock.reserved.regions),
-		 sizeof(struct memblock_region) * memblock.reserved.max);
-}
-
-/*
- * Reserve memblock.reserved.regions
- */
-int __init_memblock memblock_reserve_reserved_regions(void)
-{
-	if (memblock.reserved.regions == memblock_reserved_init_regions)
-		return 0;
-
-	return memblock_reserve(__pa(memblock.reserved.regions),
-		 sizeof(struct memblock_region) * memblock.reserved.max);
-}
-
 static void __init_memblock memblock_remove_region(struct memblock_type *type, unsigned long r)
 {
 	type->total_size -= type->regions[r].size;
@@ -184,6 +160,18 @@ static void __init_memblock memblock_remove_region(struct memblock_type *type, u
 	}
 }
 
+phys_addr_t __init_memblock get_allocated_memblock_reserved_regions_info(
+					phys_addr_t *addr)
+{
+	if (memblock.reserved.regions == memblock_reserved_init_regions)
+		return 0;
+
+	*addr = __pa(memblock.reserved.regions);
+
+	return PAGE_ALIGN(sizeof(struct memblock_region) *
+			  memblock.reserved.max);
+}
+
 /**
  * memblock_double_array - double the size of the memblock regions array
  * @type: memblock type of the regions array being doubled
@@ -204,6 +192,7 @@ static int __init_memblock memblock_double_array(struct memblock_type *type,
 						phys_addr_t new_area_size)
 {
 	struct memblock_region *new_array, *old_array;
+	phys_addr_t old_alloc_size, new_alloc_size;
 	phys_addr_t old_size, new_size, addr;
 	int use_slab = slab_is_available();
 	int *in_slab;
@@ -217,6 +206,12 @@ static int __init_memblock memblock_double_array(struct memblock_type *type,
 	/* Calculate new doubled size */
 	old_size = type->max * sizeof(struct memblock_region);
 	new_size = old_size << 1;
+	/*
+	 * We need to allocated new one align to PAGE_SIZE,
+	 *   so we can free them completely later.
+	 */
+	old_alloc_size = PAGE_ALIGN(old_size);
+	new_alloc_size = PAGE_ALIGN(new_size);
 
 	/* Retrieve the slab flag */
 	if (type == &memblock.memory)
@@ -245,11 +240,11 @@ static int __init_memblock memblock_double_array(struct memblock_type *type,
 
 		addr = memblock_find_in_range(new_area_start + new_area_size,
 						memblock.current_limit,
-						new_size, sizeof(phys_addr_t));
+						new_alloc_size, PAGE_SIZE);
 		if (!addr && new_area_size)
 			addr = memblock_find_in_range(0,
 					min(new_area_start, memblock.current_limit),
-					new_size, sizeof(phys_addr_t));
+					new_alloc_size, PAGE_SIZE);
 
 		new_array = addr ? __va(addr) : 0;
 	}
@@ -279,13 +274,13 @@ static int __init_memblock memblock_double_array(struct memblock_type *type,
 		kfree(old_array);
 	else if (old_array != memblock_memory_init_regions &&
 		 old_array != memblock_reserved_init_regions)
-		memblock_free(__pa(old_array), old_size);
+		memblock_free(__pa(old_array), old_alloc_size);
 
 	/* Reserve the new array if that comes from the memblock.
 	 * Otherwise, we needn't do it
 	 */
 	if (!use_slab)
-		BUG_ON(memblock_reserve(addr, new_size));
+		BUG_ON(memblock_reserve(addr, new_alloc_size));
 
 	/* Update slab flag */
 	*in_slab = use_slab;