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

Alastair D'Silva
2019-12-03T03:50:19Z

From: Alastair D'Silva <alastair@d-silva.org>

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@d-silva.org>
---
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