[PATCH 4/4] mm/page_alloc: initialize node_possible_map like the other node maps

[Sang-Heon Jeon <ekffu200098@gmail.com>]

node_states[N_POSSIBLE], aliased by node_possible_map, is initialized to
NODE_MASK_ALL, unlike the other entries, which are initialized with only
node 0 set.

On !NUMA, MAX_NUMNODES == 1, so initializing node_possible_map to
NODE_MASK_ALL is equivalent to initializing it with only node 0 set.

On NUMA, every architecture now sets node_possible_map after parsing its
NUMA topology, so nothing relies on the initial value.

So, instead of initializing node_possible_map to NODE_MASK_ALL, set only
node 0, like the other entries. Then NODE_MASK_ALL is no longer used, so
remove it and its only helper NODE_MASK_LAST_WORD.

No functional change.

Signed-off-by: Sang-Heon Jeon <ekffu200098@gmail.com>
---
 include/linux/nodemask.h | 20 --------------------
 mm/page_alloc.c          |  2 +-
 2 files changed, 1 insertion(+), 21 deletions(-)

diff --git a/include/linux/nodemask.h b/include/linux/nodemask.h
index b842aa525546..484fe366a94c 100644
--- a/include/linux/nodemask.h
+++ b/include/linux/nodemask.h
@@ -47,7 +47,6 @@
  *					MAX_NUMNODES
  *
  * nodemask_t nodemask_of_node(node)	Return nodemask with bit 'node' set
- * NODE_MASK_ALL			Initializer - all bits set
  * NODE_MASK_NONE			Initializer - no bits set
  * unsigned long *nodes_addr(mask)	Array of unsigned long's in mask
  *
@@ -296,25 +295,6 @@ static __always_inline unsigned int __first_unset_node(const nodemask_t *maskp)
 	return min(MAX_NUMNODES, find_first_zero_bit(maskp->bits, MAX_NUMNODES));
 }
 
-#define NODE_MASK_LAST_WORD BITMAP_LAST_WORD_MASK(MAX_NUMNODES)
-
-#if MAX_NUMNODES <= BITS_PER_LONG
-
-#define NODE_MASK_ALL							\
-((nodemask_t) { {							\
-	[BITS_TO_LONGS(MAX_NUMNODES)-1] = NODE_MASK_LAST_WORD		\
-} })
-
-#else
-
-#define NODE_MASK_ALL							\
-((nodemask_t) { {							\
-	[0 ... BITS_TO_LONGS(MAX_NUMNODES)-2] = ~0UL,			\
-	[BITS_TO_LONGS(MAX_NUMNODES)-1] = NODE_MASK_LAST_WORD		\
-} })
-
-#endif
-
 #define NODE_MASK_NONE							\
 ((nodemask_t) { {							\
 	[0 ... BITS_TO_LONGS(MAX_NUMNODES)-1] =  0UL			\
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 784a6e2f8ba0..c0f17dede824 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -191,7 +191,7 @@ EXPORT_SYMBOL(latent_entropy);
  * Array of node states.
  */
 nodemask_t node_states[NR_NODE_STATES] __read_mostly = {
-	[N_POSSIBLE] = NODE_MASK_ALL,
+	[N_POSSIBLE] = { { [0] = 1UL } },
 	[N_ONLINE] = { { [0] = 1UL } },
 #ifndef CONFIG_NUMA
 	[N_NORMAL_MEMORY] = { { [0] = 1UL } },
-- 
2.43.0