From: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Subject: mm/mmzone.h: simplify is_highmem_idx()
There is a lot of historical ifdefery in is_highmem_idx() and its helper
zone_movable_is_highmem() that was required because of two different paths
for nodes and zones initialization that were selected at compile time.
Until commit 3f08a302f533 ("mm: remove CONFIG_HAVE_MEMBLOCK_NODE_MAP
option") the movable_zone variable was only available for configurations
that had CONFIG_HAVE_MEMBLOCK_NODE_MAP enabled so the test in
zone_movable_is_highmem() used that variable only for such configurations.
For other configurations the test checked if the index of ZONE_MOVABLE
was greater by 1 than the index of ZONE_HIGMEM and then movable zone was
considered a highmem zone. Needless to say, ZONE_MOVABLE - 1 equals
ZONE_HIGHMEM by definition when CONFIG_HIGHMEM=y.
Commit 3f08a302f533 ("mm: remove CONFIG_HAVE_MEMBLOCK_NODE_MAP option")
made movable_zone variable always available. Since this variable is set
to ZONE_HIGHMEM if CONFIG_HIGHMEM is enabled and highmem zone is
populated, it is enough to check whether
zone_idx == ZONE_MOVABLE && movable_zone == ZONE_HIGMEM
to test if zone index points to a highmem zone.
Remove zone_movable_is_highmem() that is not used anywhere except
is_highmem_idx() and use the test above in is_highmem_idx() instead.
Link: https://lkml.kernel.org/r/20210426141927.1314326-3-rppt@xxxxxxxxxx
Signed-off-by: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Reviewed-by: Anshuman Khandual <anshuman.khandual@xxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/mmzone.h | 13 +------------
1 file changed, 1 insertion(+), 12 deletions(-)
--- a/include/linux/mmzone.h~mm-mmzoneh-simplify-is_highmem_idx
+++ a/include/linux/mmzone.h
@@ -982,22 +982,11 @@ static inline void zone_set_nid(struct z
extern int movable_zone;
-#ifdef CONFIG_HIGHMEM
-static inline int zone_movable_is_highmem(void)
-{
-#ifdef CONFIG_NEED_MULTIPLE_NODES
- return movable_zone == ZONE_HIGHMEM;
-#else
- return (ZONE_MOVABLE - 1) == ZONE_HIGHMEM;
-#endif
-}
-#endif
-
static inline int is_highmem_idx(enum zone_type idx)
{
#ifdef CONFIG_HIGHMEM
return (idx == ZONE_HIGHMEM ||
- (idx == ZONE_MOVABLE && zone_movable_is_highmem()));
+ (idx == ZONE_MOVABLE && movable_zone == ZONE_HIGHMEM));
#else
return 0;
#endif
_
