slab: pass struct kmem_cache_args to do_kmem_cache_create()

and initialize most things in do_kmem_cache_create(). In a follow-up
patch we'll remove rcu_freeptr_offset from struct kmem_cache.
Reviewed-by: Kees Cook <kees@kernel.org>
Reviewed-by: Jens Axboe <axboe@kernel.dk>
Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Christian Brauner <brauner@kernel.org>
Reviewed-by: Roman Gushchin <roman.gushchin@linux.dev>
Signed-off-by: Vlastimil Babka <vbabka@suse.cz>

mm/slab.h

@@ -424,7 +424,9 @@ kmalloc_slab(size_t size, kmem_buckets *b, gfp_t flags, unsigned long caller)
 gfp_t kmalloc_fix_flags(gfp_t flags);
 
 /* Functions provided by the slab allocators */
-int do_kmem_cache_create(struct kmem_cache *, slab_flags_t flags);
+int do_kmem_cache_create(struct kmem_cache *s, const char *name,
+			 unsigned int size, struct kmem_cache_args *args,
+			 slab_flags_t flags);
 
 void __init kmem_cache_init(void);
 extern void create_boot_cache(struct kmem_cache *, const char *name,

mm/slab_common.c

@@ -224,20 +224,7 @@ static struct kmem_cache *create_cache(const char *name,
 	s = kmem_cache_zalloc(kmem_cache, GFP_KERNEL);
 	if (!s)
 		goto out;
-
-	s->name = name;
-	s->size = s->object_size = object_size;
-	if (args->use_freeptr_offset)
-		s->rcu_freeptr_offset = args->freeptr_offset;
-	else
-		s->rcu_freeptr_offset = UINT_MAX;
-	s->align = args->align;
-	s->ctor = args->ctor;
-#ifdef CONFIG_HARDENED_USERCOPY
-	s->useroffset = args->useroffset;
-	s->usersize = args->usersize;
-#endif
-	err = do_kmem_cache_create(s, flags);
+	err = do_kmem_cache_create(s, name, object_size, args, flags);
 	if (err)
 		goto out_free_cache;
 
@@ -788,9 +775,7 @@ void __init create_boot_cache(struct kmem_cache *s, const char *name,
 {
 	int err;
 	unsigned int align = ARCH_KMALLOC_MINALIGN;
-
-	s->name = name;
-	s->size = s->object_size = size;
+	struct kmem_cache_args kmem_args = {};
 
 	/*
 	 * kmalloc caches guarantee alignment of at least the largest
@@ -799,14 +784,14 @@ void __init create_boot_cache(struct kmem_cache *s, const char *name,
 	 */
 	if (flags & SLAB_KMALLOC)
 		align = max(align, 1U << (ffs(size) - 1));
-	s->align = calculate_alignment(flags, align, size);
+	kmem_args.align = calculate_alignment(flags, align, size);
 
 #ifdef CONFIG_HARDENED_USERCOPY
-	s->useroffset = useroffset;
-	s->usersize = usersize;
+	kmem_args.useroffset = useroffset;
+	kmem_args.usersize = usersize;
 #endif
 
-	err = do_kmem_cache_create(s, flags);
+	err = do_kmem_cache_create(s, name, size, &kmem_args, flags);
 
 	if (err)
 		panic("Creation of kmalloc slab %s size=%u failed. Reason %d\n",

mm/slub.c

@@ -5843,14 +5843,29 @@ __kmem_cache_alias(const char *name, unsigned int size, unsigned int align,
 	return s;
 }
 
-int do_kmem_cache_create(struct kmem_cache *s, slab_flags_t flags)
+int do_kmem_cache_create(struct kmem_cache *s, const char *name,
+			 unsigned int size, struct kmem_cache_args *args,
+			 slab_flags_t flags)
 {
 	int err = -EINVAL;
 
+	s->name = name;
+	s->size = s->object_size = size;
+
 	s->flags = kmem_cache_flags(flags, s->name);
 #ifdef CONFIG_SLAB_FREELIST_HARDENED
 	s->random = get_random_long();
 #endif
+	if (args->use_freeptr_offset)
+		s->rcu_freeptr_offset = args->freeptr_offset;
+	else
+		s->rcu_freeptr_offset = UINT_MAX;
+	s->align = args->align;
+	s->ctor = args->ctor;
+#ifdef CONFIG_HARDENED_USERCOPY
+	s->useroffset = args->useroffset;
+	s->usersize = args->usersize;
+#endif
 
 	if (!calculate_sizes(s))
 		goto out;