mm: move page zone helpers from mm.h to mmzone.h

It makes more sense to have these helpers in zone specific header
file, rather than the generic mm.h

Link: https://lkml.kernel.org/r/20220715150521.18165-3-alex.sierra@amd.com
Signed-off-by: Alex Sierra <alex.sierra@amd.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: David Hildenbrand <david@redhat.com>
Cc: Felix Kuehling <Felix.Kuehling@amd.com>
Cc: Jason Gunthorpe <jgg@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 80 insertions, 0 deletions

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 735bf5b37949..5da1135e6755 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -730,6 +730,86 @@ static inline bool zone_is_empty(struct zone *zone)
 	return zone->spanned_pages == 0;
 }
 
+#ifndef BUILD_VDSO32_64
+/*
+ * The zone field is never updated after free_area_init_core()
+ * sets it, so none of the operations on it need to be atomic.
+ */
+
+/* Page flags: | [SECTION] | [NODE] | ZONE | [LAST_CPUPID] | ... | FLAGS | */
+#define SECTIONS_PGOFF		((sizeof(unsigned long)*8) - SECTIONS_WIDTH)
+#define NODES_PGOFF		(SECTIONS_PGOFF - NODES_WIDTH)
+#define ZONES_PGOFF		(NODES_PGOFF - ZONES_WIDTH)
+#define LAST_CPUPID_PGOFF	(ZONES_PGOFF - LAST_CPUPID_WIDTH)
+#define KASAN_TAG_PGOFF		(LAST_CPUPID_PGOFF - KASAN_TAG_WIDTH)
+
+/*
+ * Define the bit shifts to access each section.  For non-existent
+ * sections we define the shift as 0; that plus a 0 mask ensures
+ * the compiler will optimise away reference to them.
+ */
+#define SECTIONS_PGSHIFT	(SECTIONS_PGOFF * (SECTIONS_WIDTH != 0))
+#define NODES_PGSHIFT		(NODES_PGOFF * (NODES_WIDTH != 0))
+#define ZONES_PGSHIFT		(ZONES_PGOFF * (ZONES_WIDTH != 0))
+#define LAST_CPUPID_PGSHIFT	(LAST_CPUPID_PGOFF * (LAST_CPUPID_WIDTH != 0))
+#define KASAN_TAG_PGSHIFT	(KASAN_TAG_PGOFF * (KASAN_TAG_WIDTH != 0))
+
+/* NODE:ZONE or SECTION:ZONE is used to ID a zone for the buddy allocator */
+#ifdef NODE_NOT_IN_PAGE_FLAGS
+#define ZONEID_SHIFT		(SECTIONS_SHIFT + ZONES_SHIFT)
+#define ZONEID_PGOFF		((SECTIONS_PGOFF < ZONES_PGOFF) ? \
+						SECTIONS_PGOFF : ZONES_PGOFF)
+#else
+#define ZONEID_SHIFT		(NODES_SHIFT + ZONES_SHIFT)
+#define ZONEID_PGOFF		((NODES_PGOFF < ZONES_PGOFF) ? \
+						NODES_PGOFF : ZONES_PGOFF)
+#endif
+
+#define ZONEID_PGSHIFT		(ZONEID_PGOFF * (ZONEID_SHIFT != 0))
+
+#define ZONES_MASK		((1UL << ZONES_WIDTH) - 1)
+#define NODES_MASK		((1UL << NODES_WIDTH) - 1)
+#define SECTIONS_MASK		((1UL << SECTIONS_WIDTH) - 1)
+#define LAST_CPUPID_MASK	((1UL << LAST_CPUPID_SHIFT) - 1)
+#define KASAN_TAG_MASK		((1UL << KASAN_TAG_WIDTH) - 1)
+#define ZONEID_MASK		((1UL << ZONEID_SHIFT) - 1)
+
+static inline enum zone_type page_zonenum(const struct page *page)
+{
+	ASSERT_EXCLUSIVE_BITS(page->flags, ZONES_MASK << ZONES_PGSHIFT);
+	return (page->flags >> ZONES_PGSHIFT) & ZONES_MASK;
+}
+
+static inline enum zone_type folio_zonenum(const struct folio *folio)
+{
+	return page_zonenum(&folio->page);
+}
+
+#ifdef CONFIG_ZONE_DEVICE
+static inline bool is_zone_device_page(const struct page *page)
+{
+	return page_zonenum(page) == ZONE_DEVICE;
+}
+extern void memmap_init_zone_device(struct zone *, unsigned long,
+				    unsigned long, struct dev_pagemap *);
+#else
+static inline bool is_zone_device_page(const struct page *page)
+{
+	return false;
+}
+#endif
+
+static inline bool folio_is_zone_device(const struct folio *folio)
+{
+	return is_zone_device_page(&folio->page);
+}
+
+static inline bool is_zone_movable_page(const struct page *page)
+{
+	return page_zonenum(page) == ZONE_MOVABLE;
+}
+#endif
+
 /*
  * Return true if [start_pfn, start_pfn + nr_pages) range has a non-empty
  * intersection with the given zone