[PATCH v4 3/8] mm/memory_hotplug: guard more declarations by CONFIG_MEMORY_HOTPLUG

From: David Hildenbrand
Date: Fri Sep 11 2020 - 06:35:54 EST

We soon want to pass flags via a new type to add_memory() and friends.
That revealed that we currently don't guard some declarations by

While some definitions could be moved to different places, let's keep it
minimal for now and use CONFIG_MEMORY_HOTPLUG for all functions only

Wrap sparse_decode_mem_map() into CONFIG_MEMORY_HOTPLUG, it's only
called from CONFIG_MEMORY_HOTPLUG code.

While at it, remove allow_online_pfn_range(), which is no longer around,
and mhp_notimplemented(), which is unused.

Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxxx>
Cc: Dan Williams <dan.j.williams@xxxxxxxxx>
Cc: Pankaj Gupta <pankaj.gupta.linux@xxxxxxxxx>
Cc: Baoquan He <bhe@xxxxxxxxxx>
Cc: Wei Yang <richardw.yang@xxxxxxxxxxxxxxx>
Signed-off-by: David Hildenbrand <david@xxxxxxxxxx>
include/linux/memory_hotplug.h | 12 +++---------
mm/sparse.c | 2 ++
2 files changed, 5 insertions(+), 9 deletions(-)

diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index 51a877fec8da8..1504b4d5ae6ce 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -247,13 +247,6 @@ static inline void zone_span_writelock(struct zone *zone) {}
static inline void zone_span_writeunlock(struct zone *zone) {}
static inline void zone_seqlock_init(struct zone *zone) {}

-static inline int mhp_notimplemented(const char *func)
- printk(KERN_WARNING "%s() called, with CONFIG_MEMORY_HOTPLUG disabled\n", func);
- dump_stack();
- return -ENOSYS;
static inline void register_page_bootmem_info_node(struct pglist_data *pgdat)
@@ -344,6 +337,7 @@ static inline void __remove_memory(int nid, u64 start, u64 size) {}
extern void set_zone_contiguous(struct zone *zone);
extern void clear_zone_contiguous(struct zone *zone);

extern void __ref free_area_init_core_hotplug(int nid);
extern int __add_memory(int nid, u64 start, u64 size);
extern int add_memory(int nid, u64 start, u64 size);
@@ -364,8 +358,8 @@ extern void sparse_remove_section(struct mem_section *ms,
unsigned long map_offset, struct vmem_altmap *altmap);
extern struct page *sparse_decode_mem_map(unsigned long coded_mem_map,
unsigned long pnum);
-extern bool allow_online_pfn_range(int nid, unsigned long pfn, unsigned long nr_pages,
- int online_type);
extern struct zone *zone_for_pfn_range(int online_type, int nid, unsigned start_pfn,
unsigned long nr_pages);
diff --git a/mm/sparse.c b/mm/sparse.c
index b25ad8e648392..7bd23f9d6cef6 100644
--- a/mm/sparse.c
+++ b/mm/sparse.c
@@ -312,6 +312,7 @@ static unsigned long sparse_encode_mem_map(struct page *mem_map, unsigned long p
return coded_mem_map;

* Decode mem_map from the coded memmap
@@ -321,6 +322,7 @@ struct page *sparse_decode_mem_map(unsigned long coded_mem_map, unsigned long pn
coded_mem_map &= SECTION_MAP_MASK;
return ((struct page *)coded_mem_map) + section_nr_to_pfn(pnum);

static void __meminit sparse_init_one_section(struct mem_section *ms,
unsigned long pnum, struct page *mem_map,