mm/hugetlb: add folio_hstate()

[ Upstream commit e51da3a ]

Helper function to retrieve hstate information from a hugetlb folio.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Sidhartha Kumar <[email protected]>
Reported-by: kernel test robot <[email protected]>
Reviewed-by: Mike Kravetz <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Colin Cross <[email protected]>
Cc: David Howells <[email protected]>
Cc: "Eric W . Biederman" <[email protected]>
Cc: Hugh Dickins <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Muchun Song <[email protected]>
Cc: Peter Xu <[email protected]>
Cc: Vlastimil Babka <[email protected]>
Cc: William Kucharski <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Stable-dep-of: b76b469 ("mm/hugetlb: fix missing hugetlb_lock for resv uncharge")
Signed-off-by: Sasha Levin <[email protected]>

Author: sidkumar99

include/linux/hugetlb.h

@@ -863,10 +863,15 @@ static inline pte_t arch_make_huge_pte(pte_t entry, unsigned int shift,
 }
 #endif
 
+static inline struct hstate *folio_hstate(struct folio *folio)
+{
+	VM_BUG_ON_FOLIO(!folio_test_hugetlb(folio), folio);
+	return size_to_hstate(folio_size(folio));
+}
+
 static inline struct hstate *page_hstate(struct page *page)
 {
-	VM_BUG_ON_PAGE(!PageHuge(page), page);
-	return size_to_hstate(page_size(page));
+	return folio_hstate(page_folio(page));
 }
 
 static inline unsigned hstate_index_to_shift(unsigned index)
@@ -1077,6 +1082,11 @@ static inline struct hstate *hstate_vma(struct vm_area_struct *vma)
 	return NULL;
 }
 
+static inline struct hstate *folio_hstate(struct folio *folio)
+{
+	return NULL;
+}
+
 static inline struct hstate *page_hstate(struct page *page)
 {
 	return NULL;

mm/migrate.c

@@ -1632,7 +1632,7 @@ struct page *alloc_migration_target(struct page *page, unsigned long private)
 		nid = folio_nid(folio);
 
 	if (folio_test_hugetlb(folio)) {
-		struct hstate *h = page_hstate(&folio->page);
+		struct hstate *h = folio_hstate(folio);
 
 		gfp_mask = htlb_modify_alloc_mask(h, gfp_mask);
 		return alloc_huge_page_nodemask(h, nid, mtc->nmask, gfp_mask);