[PATCH v4 02/25] mm/memory_hotplug: Allow check_hotplug_memory_addressable to be called from drivers

[Alastair D'Silva]

When setting up OpenCAPI connected persistent memory, the range check may
not be performed until quite late (or perhaps not at all, if the user does
not establish a DAX device).

This patch makes the range check callable so we can perform the check while
probing the OpenCAPI Persistent Memory device.

Signed-off-by: Alastair D'Silva <alastair@xxxxxxxxxxx>
Reviewed-by: Andrew Donnellan <ajd@xxxxxxxxxxxxx>
---
 include/linux/memory_hotplug.h | 5 +++++
 mm/memory_hotplug.c            | 4 ++--
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/include/linux/memory_hotplug.h b/include/linux/memory_hotplug.h
index f4d59155f3d4..9a19ae0d7e31 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -337,6 +337,11 @@ 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);
 
+#ifdef CONFIG_MEMORY_HOTPLUG_SPARSE
+int check_hotplug_memory_addressable(unsigned long pfn,
+				     unsigned long nr_pages);
+#endif /* CONFIG_MEMORY_HOTPLUG_SPARSE */
+
 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);
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 0a54ffac8c68..14945f033594 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -276,8 +276,8 @@ static int check_pfn_span(unsigned long pfn, unsigned long nr_pages,
 	return 0;
 }
 
-static int check_hotplug_memory_addressable(unsigned long pfn,
-					    unsigned long nr_pages)
+int check_hotplug_memory_addressable(unsigned long pfn,
+				     unsigned long nr_pages)
 {
 	const u64 max_addr = PFN_PHYS(pfn + nr_pages) - 1;
 
-- 
2.24.1