Merge tag 'slab-for-5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab

Pull slab updates from Vlastimil Babka:

 - Separate struct slab from struct page - an offshot of the page folio
   work.

   Struct page fields used by slab allocators are moved from struct page
   to a new struct slab, that uses the same physical storage. Similar to
   struct folio, it always is a head page. This brings better type
   safety, separation of large kmalloc allocations from true slabs, and
   cleanup of related objcg code.

 - A SLAB_MERGE_DEFAULT config optimization.

* tag 'slab-for-5.17' of git://git.kernel.org/pub/scm/linux/kernel/git/vbabka/slab: (33 commits)
  mm/slob: Remove unnecessary page_mapcount_reset() function call
  bootmem: Use page->index instead of page->freelist
  zsmalloc: Stop using slab fields in struct page
  mm/slub: Define struct slab fields for CONFIG_SLUB_CPU_PARTIAL only when enabled
  mm/slub: Simplify struct slab slabs field definition
  mm/sl*b: Differentiate struct slab fields by sl*b implementations
  mm/kfence: Convert kfence_guarded_alloc() to struct slab
  mm/kasan: Convert to struct folio and struct slab
  mm/slob: Convert SLOB to use struct slab and struct folio
  mm/memcg: Convert slab objcgs from struct page to struct slab
  mm: Convert struct page to struct slab in functions used by other subsystems
  mm/slab: Finish struct page to struct slab conversion
  mm/slab: Convert most struct page to struct slab by spatch
  mm/slab: Convert kmem_getpages() and kmem_freepages() to struct slab
  mm/slub: Finish struct page to struct slab conversion
  mm/slub: Convert most struct page to struct slab by spatch
  mm/slub: Convert pfmemalloc_match() to take a struct slab
  mm/slub: Convert __free_slab() to use struct slab
  mm/slub: Convert alloc_slab_page() to return a struct slab
  mm/slub: Convert print_page_info() to print_slab_info()
  ...

2 files changed, 12 insertions, 11 deletions

diff --git a/mm/kfence/core.c b/mm/kfence/core.c
index a19154a8d196..5ad40e3add45 100644
--- a/mm/kfence/core.c
+++ b/mm/kfence/core.c
@@ -360,7 +360,7 @@ static void *kfence_guarded_alloc(struct kmem_cache *cache, size_t size, gfp_t g
 {
 	struct kfence_metadata *meta = NULL;
 	unsigned long flags;
-	struct page *page;
+	struct slab *slab;
 	void *addr;
 
 	/* Try to obtain a free object. */
@@ -424,13 +424,14 @@ static void *kfence_guarded_alloc(struct kmem_cache *cache, size_t size, gfp_t g
 
 	alloc_covered_add(alloc_stack_hash, 1);
 
-	/* Set required struct page fields. */
-	page = virt_to_page(meta->addr);
-	page->slab_cache = cache;
-	if (IS_ENABLED(CONFIG_SLUB))
-		page->objects = 1;
-	if (IS_ENABLED(CONFIG_SLAB))
-		page->s_mem = addr;
+	/* Set required slab fields. */
+	slab = virt_to_slab((void *)meta->addr);
+	slab->slab_cache = cache;
+#if defined(CONFIG_SLUB)
+	slab->objects = 1;
+#elif defined(CONFIG_SLAB)
+	slab->s_mem = addr;
+#endif
 
 	/* Memory initialization. */
 	for_each_canary(meta, set_canary_byte);
diff --git a/mm/kfence/kfence_test.c b/mm/kfence/kfence_test.c
index 695030c1fff8..a22b1af85577 100644
--- a/mm/kfence/kfence_test.c
+++ b/mm/kfence/kfence_test.c
@@ -282,7 +282,7 @@ static void *test_alloc(struct kunit *test, size_t size, gfp_t gfp, enum allocat
 			alloc = kmalloc(size, gfp);
 
 		if (is_kfence_address(alloc)) {
-			struct page *page = virt_to_head_page(alloc);
+			struct slab *slab = virt_to_slab(alloc);
 			struct kmem_cache *s = test_cache ?:
 					kmalloc_caches[kmalloc_type(GFP_KERNEL)][__kmalloc_index(size, false)];
 
@@ -291,8 +291,8 @@ static void *test_alloc(struct kunit *test, size_t size, gfp_t gfp, enum allocat
 			 * even for KFENCE objects; these are required so that
 			 * memcg accounting works correctly.
 			 */
-			KUNIT_EXPECT_EQ(test, obj_to_index(s, page, alloc), 0U);
-			KUNIT_EXPECT_EQ(test, objs_per_slab_page(s, page), 1);
+			KUNIT_EXPECT_EQ(test, obj_to_index(s, slab, alloc), 0U);
+			KUNIT_EXPECT_EQ(test, objs_per_slab(s, slab), 1);
 
 			if (policy == ALLOCATE_ANY)
 				return alloc;