[PATCH v2 04/27] mm/memory_hotplug: Allow check_hotplug_memory_addressable to be called from drivers

[Alastair D'Silva]

From: Alastair D'Silva <alastair@xxxxxxxxxxx>

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 SCM device.

Signed-off-by: Alastair D'Silva <alastair@xxxxxxxxxxx>
---
 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 f46ea71b4ffd..3f3a010b60d2 100644
--- a/include/linux/memory_hotplug.h
+++ b/include/linux/memory_hotplug.h
@@ -339,6 +339,11 @@ static inline int remove_memory(int nid, u64 start, u64 size)
 static inline void __remove_memory(int nid, u64 start, u64 size) {}
 #endif /* CONFIG_MEMORY_HOTREMOVE */
 
+#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 b5be827ecda5..abd9624bd0c1 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -278,8 +278,8 @@ 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;
 
-- 
2.23.0