1 files changed, 9 insertions, 41 deletions

diff --git a/mm/debug.c b/mm/debug.c
index db83e381a8ae..b4388f4dcd4d 100644
--- a/mm/debug.c
+++ b/mm/debug.c
@@ -71,10 +71,12 @@ static void __dump_folio(struct folio *folio, struct page *page,
 		unsigned long pfn, unsigned long idx)
 {
 	struct address_space *mapping = folio_mapping(folio);
-	int mapcount = atomic_read(&page->_mapcount);
+	int mapcount = atomic_read(&page->_mapcount) + 1;
 	char *type = "";
 
-	mapcount = page_mapcount_is_type(mapcount) ? 0 : mapcount + 1;
+	if (page_mapcount_is_type(mapcount))
+		mapcount = 0;
+
 	pr_warn("page: refcount:%d mapcount:%d mapping:%p index:%#lx pfn:%#lx\n",
 			folio_ref_count(folio), mapcount, mapping,
 			folio->index + idx, pfn);
@@ -127,47 +129,13 @@ static void __dump_folio(struct folio *folio, struct page *page,
 
 static void __dump_page(const struct page *page)
 {
-	struct folio *foliop, folio;
-	struct page precise;
-	unsigned long head;
-	unsigned long pfn = page_to_pfn(page);
-	unsigned long idx, nr_pages = 1;
-	int loops = 5;
-
-again:
-	memcpy(&precise, page, sizeof(*page));
-	head = precise.compound_head;
-	if ((head & 1) == 0) {
-		foliop = (struct folio *)&precise;
-		idx = 0;
-		if (!folio_test_large(foliop))
-			goto dump;
-		foliop = (struct folio *)page;
-	} else {
-		foliop = (struct folio *)(head - 1);
-		idx = folio_page_idx(foliop, page);
-	}
+	struct page_snapshot ps;
 
-	if (idx < MAX_FOLIO_NR_PAGES) {
-		memcpy(&folio, foliop, 2 * sizeof(struct page));
-		nr_pages = folio_nr_pages(&folio);
-		if (nr_pages > 1)
-			memcpy(&folio.__page_2, &foliop->__page_2,
-			       sizeof(struct page));
-		foliop = &folio;
-	}
-
-	if (idx > nr_pages) {
-		if (loops-- > 0)
-			goto again;
+	snapshot_page(&ps, page);
+	if (!snapshot_page_is_faithful(&ps))
 		pr_warn("page does not match folio\n");
-		precise.compound_head &= ~1UL;
-		foliop = (struct folio *)&precise;
-		idx = 0;
-	}
 
-dump:
-	__dump_folio(foliop, &precise, pfn, idx);
+	__dump_folio(&ps.folio_snapshot, &ps.page_snapshot, ps.pfn, ps.idx);
 }
 
 void dump_page(const struct page *page, const char *reason)
@@ -288,7 +256,7 @@ void dump_vmg(const struct vma_merge_struct *vmg, const char *reason)
 		vmg->vmi, vmg->vmi ? vma_iter_addr(vmg->vmi) : 0,
 		vmg->vmi ? vma_iter_end(vmg->vmi) : 0,
 		vmg->prev, vmg->middle, vmg->next, vmg->target,
-		vmg->start, vmg->end, vmg->flags,
+		vmg->start, vmg->end, vmg->vm_flags,
 		vmg->file, vmg->anon_vma, vmg->policy,
 #ifdef CONFIG_USERFAULTFD
 		vmg->uffd_ctx.ctx,