[PATCH v3 08/17] slab: Remove folio references from kvfree()

["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 | 10 +++++-----
 1 file changed, 5 insertions(+), 5 deletions(-)

diff --git a/mm/slub.c b/mm/slub.c
index debe7132b343..100ed979312d 100644
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -6809,7 +6809,7 @@ void kvfree_rcu_cb(struct rcu_head *head)
  */
 void kfree(const void *object)
 {
-	struct folio *folio;
+	struct page *page;
 	struct slab *slab;
 	struct kmem_cache *s;
 	void *x = (void *)object;
@@ -6819,13 +6819,13 @@ void kfree(const void *object)
 	if (unlikely(ZERO_OR_NULL_PTR(object)))
 		return;
 
-	folio = virt_to_folio(object);
-	if (unlikely(!folio_test_slab(folio))) {
-		free_large_kmalloc(&folio->page, (void *)object);
+	page = virt_to_page(object);
+	if (unlikely(PageLargeKmalloc(page))) {
+		free_large_kmalloc(page, (void *)object);
 		return;
 	}
 
-	slab = folio_slab(folio);
+	slab = page_slab(page);
 	s = slab->slab_cache;
 	slab_free(s, slab, x, _RET_IP_);
 }
-- 
2.47.2