[PATCH 14/22] slab: Remove folio references from __do_krealloc()

["Matthew Wilcox (Oracle)" <willy@infradead.org>]

As with memcg_slab_post_charge(), we save a call to compound_head()
for large kmallocs.  This has a slight change of behaviour in that
non-vmalloc, non-slab, non-kmalloc pointers will now cause a NULL
pointer dereference rather than a warning.  We could add that back if
really needed.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
---
 mm/slub.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index e471716cbde3..f31206e5c89a 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -6320,16 +6320,16 @@ __do_krealloc(const void *p, size_t new_size, unsigned long align, gfp_t flags,
 	if (is_kfence_address(p)) {
 		ks = orig_size = kfence_ksize(p);
 	} else {
-		struct folio *folio;
+		struct page *page;
 
-		folio = virt_to_folio(p);
-		if (unlikely(!folio_test_slab(folio))) {
+		page = virt_to_page(p);
+		if (unlikely(PageLargeKmalloc(page))) {
 			/* Big kmalloc object */
-			WARN_ON(folio_size(folio) <= KMALLOC_MAX_CACHE_SIZE);
-			WARN_ON(p != folio_address(folio));
-			ks = folio_size(folio);
+			ks = page_size(page);
+			WARN_ON(ks <= KMALLOC_MAX_CACHE_SIZE);
+			WARN_ON(p != page_address(page));
 		} else {
-			s = folio_slab(folio)->slab_cache;
+			s = page_slab(page)->slab_cache;
 			orig_size = get_orig_size(s, (void *)p);
 			ks = s->object_size;
 		}
-- 
2.47.2