[PATCH v2 07/22] numa: Introduce a generic memory_add_physaddr_to_nid()

[Dan Williams <dan.j.williams@xxxxxxxxx>]

For architectures that opt into storing their numa data in memblock
(only ARM64 currently), add a memblock generic way to interrogate that
data for memory_add_physaddr_to_nid(). This requires ARCH_KEEP_MEMBLOCK
to keep memblock text and data around after boot.

Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Cc: Jia He <justin.he@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Dan Williams <dan.j.williams@xxxxxxxxx>
---
 include/linux/mm.h |   11 +++++++++++
 mm/Kconfig         |    6 ++++++
 mm/page_alloc.c    |   23 ++++++++++++++++++++++-
 3 files changed, 39 insertions(+), 1 deletion(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index dc7b87310c10..1e76ee5da20b 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -2425,6 +2425,17 @@ unsigned long __absent_pages_in_range(int nid, unsigned long start_pfn,
 						unsigned long end_pfn);
 extern unsigned long absent_pages_in_range(unsigned long start_pfn,
 						unsigned long end_pfn);
+
+/*
+ * Allow archs to opt-in to keeping get_pfn_range_for_nid() available
+ * after boot.
+ */
+#ifdef CONFIG_ARCH_KEEP_MEMBLOCK
+#define __init_or_memblock
+#else
+#define __init_or_memblock __init
+#endif
+
 extern void get_pfn_range_for_nid(unsigned int nid,
 			unsigned long *start_pfn, unsigned long *end_pfn);
 extern unsigned long find_min_pfn_with_active_regions(void);
diff --git a/mm/Kconfig b/mm/Kconfig
index 0051f735ad98..178ed76cae1b 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -139,6 +139,12 @@ config HAVE_FAST_GUP
 config ARCH_KEEP_MEMBLOCK
 	bool
 
+# If the arch populates numa data into memblock, it can use memblock
+# apis to interrogate that data at runtime.
+config MEMBLOCK_NUMA_INFO
+	bool
+	depends on ARCH_KEEP_MEMBLOCK
+
 config MEMORY_ISOLATION
 	bool
 
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 48eb0f1410d4..df8bd169dbb4 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6351,7 +6351,7 @@ void __init sparse_memory_present_with_active_regions(int nid)
  * with no available memory, a warning is printed and the start and end
  * PFNs will be 0.
  */
-void __init get_pfn_range_for_nid(unsigned int nid,
+void __init_or_memblock get_pfn_range_for_nid(unsigned int nid,
 			unsigned long *start_pfn, unsigned long *end_pfn)
 {
 	unsigned long this_start_pfn, this_end_pfn;
@@ -6369,6 +6369,27 @@ void __init get_pfn_range_for_nid(unsigned int nid,
 		*start_pfn = 0;
 }
 
+/*
+ * Generic implementation of memory_add_physaddr_to_nid() depends on
+ * architecture using memblock data for numa information.
+ */
+#ifdef CONFIG_MEMBLOCK_NUMA_INFO
+int __init_or_memblock memory_add_physaddr_to_nid(u64 addr)
+{
+	unsigned long start_pfn, end_pfn, pfn = PHYS_PFN(addr);
+	int nid;
+
+	for_each_online_node(nid) {
+		get_pfn_range_for_nid(nid, &start_pfn, &end_pfn);
+		if (pfn >= start_pfn && pfn <= end_pfn)
+			return nid;
+	}
+	/* Default to node0 as not all callers are prepared for this to fail */
+	return 0;
+}
+EXPORT_SYMBOL_GPL(memory_add_physaddr_to_nid);
+#endif /* CONFIG_MEMBLOCK_NUMA_INFO */
+
 /*
  * This finds a zone that can be used for ZONE_MOVABLE pages. The
  * assumption is made that zones within a node are ordered in monotonic