mm: move mirrored memory specific code outside of memmap_init_zone

memmap_init_zone, is getting complex, because it is called from different
contexts: hotplug, and during boot, and also because it must handle some
architecture quirks.  One of them is mirrored memory.

Move the code that decides whether to skip mirrored memory outside of
memmap_init_zone, into a separate function.

[pasha.tatashin@oracle.com: uninline overlap_memmap_init()]
  Link: http://lkml.kernel.org/r/20180726193509.3326-4-pasha.tatashin@oracle.com
Link: http://lkml.kernel.org/r/20180724235520.10200-4-pasha.tatashin@oracle.comSigned-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
Reviewed-by: Oscar Salvador <osalvador@suse.de>
Cc: Pasha Tatashin <Pavel.Tatashin@microsoft.com>
Cc: Abdul Haleem <abdhalee@linux.vnet.ibm.com>
Cc: Baoquan He <bhe@redhat.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Cc: Steven Sistare <steven.sistare@oracle.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richard.weiyang@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/page_alloc.c

@@ -5450,6 +5450,30 @@ void __ref build_all_zonelists(pg_data_t *pgdat)
 #endif
 }
 
+/* If zone is ZONE_MOVABLE but memory is mirrored, it is an overlapped init */
+static bool __meminit
+overlap_memmap_init(unsigned long zone, unsigned long *pfn)
+{
+#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
+	static struct memblock_region *r;
+
+	if (mirrored_kernelcore && zone == ZONE_MOVABLE) {
+		if (!r || *pfn >= memblock_region_memory_end_pfn(r)) {
+			for_each_memblock(memory, r) {
+				if (*pfn < memblock_region_memory_end_pfn(r))
+					break;
+			}
+		}
+		if (*pfn >= memblock_region_memory_base_pfn(r) &&
+		    memblock_is_mirror(r)) {
+			*pfn = memblock_region_memory_end_pfn(r);
+			return true;
+		}
+	}
+#endif
+	return false;
+}
+
 /*
  * Initially all pages are reserved - free ones are freed
  * up by free_all_bootmem() once the early boot process is
@@ -5459,12 +5483,8 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
 		unsigned long start_pfn, enum memmap_context context,
 		struct vmem_altmap *altmap)
 {
-	unsigned long end_pfn = start_pfn + size;
-	unsigned long pfn;
+	unsigned long pfn, end_pfn = start_pfn + size;
 	struct page *page;
-#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
-	struct memblock_region *r = NULL, *tmp;
-#endif
 
 	if (highest_memmap_pfn < end_pfn - 1)
 		highest_memmap_pfn = end_pfn - 1;
@@ -5492,39 +5512,17 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
 		 * There can be holes in boot-time mem_map[]s handed to this
 		 * function.  They do not exist on hotplugged memory.
 		 */
-		if (context != MEMMAP_EARLY)
-			goto not_early;
-
-		if (!early_pfn_valid(pfn))
-			continue;
-		if (!early_pfn_in_nid(pfn, nid))
-			continue;
-
-#ifdef CONFIG_HAVE_MEMBLOCK_NODE_MAP
-		/*
-		 * Check given memblock attribute by firmware which can affect
-		 * kernel memory layout.  If zone==ZONE_MOVABLE but memory is
-		 * mirrored, it's an overlapped memmap init. skip it.
-		 */
-		if (mirrored_kernelcore && zone == ZONE_MOVABLE) {
-			if (!r || pfn >= memblock_region_memory_end_pfn(r)) {
-				for_each_memblock(memory, tmp)
-					if (pfn < memblock_region_memory_end_pfn(tmp))
-						break;
-				r = tmp;
-			}
-			if (pfn >= memblock_region_memory_base_pfn(r) &&
-			    memblock_is_mirror(r)) {
-				/* already initialized as NORMAL */
-				pfn = memblock_region_memory_end_pfn(r);
+		if (context == MEMMAP_EARLY) {
+			if (!early_pfn_valid(pfn))
 				continue;
-			}
+			if (!early_pfn_in_nid(pfn, nid))
+				continue;
+			if (overlap_memmap_init(zone, &pfn))
+				continue;
+			if (defer_init(nid, pfn, end_pfn))
+				break;
 		}
-#endif
-		if (defer_init(nid, pfn, end_pfn))
-			break;
 
-not_early:
 		page = pfn_to_page(pfn);
 		__init_single_page(page, pfn, zone, nid);
 		if (context == MEMMAP_HOTPLUG)
@@ -5541,9 +5539,6 @@ void __meminit memmap_init_zone(unsigned long size, int nid, unsigned long zone,
 		 * can be created for invalid pages (for alignment)
 		 * check here not to call set_pageblock_migratetype() against
 		 * pfn out of zone.
-		 *
-		 * Please note that MEMMAP_HOTPLUG path doesn't clear memmap
-		 * because this is done early in sparse_add_one_section
 		 */
 		if (!(pfn & (pageblock_nr_pages - 1))) {
 			set_pageblock_migratetype(page, MIGRATE_MOVABLE);