mm/kasan: Convert to struct folio and struct slab

KASAN accesses some slab related struct page fields so we need to
convert it to struct slab. Some places are a bit simplified thanks to
kasan_addr_to_slab() encapsulating the PageSlab flag check through
virt_to_slab().  When resolving object address to either a real slab or
a large kmalloc, use struct folio as the intermediate type for testing
the slab flag to avoid unnecessary implicit compound_head().

[ vbabka@suse.cz: use struct folio, adjust to differences in previous
  patches ]

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>
Reviewed-by: Andrey Konovalov <andreyknvl@gmail.com>
Reviewed-by: Roman Gushchin <guro@fb.com>
Tested-by: Hyeongogn Yoo <42.hyeyoo@gmail.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Konovalov <andreyknvl@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: <kasan-dev@googlegroups.com>

1 files changed, 13 insertions, 10 deletions

diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index 6a1cd2d38bff..7c06db78a76c 100644
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -247,8 +247,9 @@ struct kasan_free_meta *kasan_get_free_meta(struct kmem_cache *cache,
 }
 #endif
 
-void __kasan_poison_slab(struct page *page)
+void __kasan_poison_slab(struct slab *slab)
 {
+	struct page *page = slab_page(slab);
 	unsigned long i;
 
 	for (i = 0; i < compound_nr(page); i++)
@@ -401,9 +402,9 @@ void __kasan_kfree_large(void *ptr, unsigned long ip)
 
 void __kasan_slab_free_mempool(void *ptr, unsigned long ip)
 {
-	struct page *page;
+	struct folio *folio;
 
-	page = virt_to_head_page(ptr);
+	folio = virt_to_folio(ptr);
 
 	/*
 	 * Even though this function is only called for kmem_cache_alloc and
@@ -411,12 +412,14 @@ void __kasan_slab_free_mempool(void *ptr, unsigned long ip)
 	 * !PageSlab() when the size provided to kmalloc is larger than
 	 * KMALLOC_MAX_SIZE, and kmalloc falls back onto page_alloc.
 	 */
-	if (unlikely(!PageSlab(page))) {
+	if (unlikely(!folio_test_slab(folio))) {
 		if (____kasan_kfree_large(ptr, ip))
 			return;
-		kasan_poison(ptr, page_size(page), KASAN_FREE_PAGE, false);
+		kasan_poison(ptr, folio_size(folio), KASAN_FREE_PAGE, false);
 	} else {
-		____kasan_slab_free(page->slab_cache, ptr, ip, false, false);
+		struct slab *slab = folio_slab(folio);
+
+		____kasan_slab_free(slab->slab_cache, ptr, ip, false, false);
 	}
 }
 
@@ -560,7 +563,7 @@ void * __must_check __kasan_kmalloc_large(const void *ptr, size_t size,
 
 void * __must_check __kasan_krealloc(const void *object, size_t size, gfp_t flags)
 {
-	struct page *page;
+	struct slab *slab;
 
 	if (unlikely(object == ZERO_SIZE_PTR))
 		return (void *)object;
@@ -572,13 +575,13 @@ void * __must_check __kasan_krealloc(const void *object, size_t size, gfp_t flag
 	 */
 	kasan_unpoison(object, size, false);
 
-	page = virt_to_head_page(object);
+	slab = virt_to_slab(object);
 
 	/* Piggy-back on kmalloc() instrumentation to poison the redzone. */
-	if (unlikely(!PageSlab(page)))
+	if (unlikely(!slab))
 		return __kasan_kmalloc_large(object, size, flags);
 	else
-		return ____kasan_kmalloc(page->slab_cache, object, size, flags);
+		return ____kasan_kmalloc(slab->slab_cache, object, size, flags);
 }
 
 bool __kasan_check_byte(const void *address, unsigned long ip)