kasan: only define kasan_metadata_size for Generic mode

KASAN provides a helper for calculating the size of per-object metadata
stored in the redzone.

As now only the Generic mode uses per-object metadata, only define
kasan_metadata_size() for this mode.

Link: https://lkml.kernel.org/r/8f81d4938b80446bc72538a08217009f328a3e23.1662411799.git.andreyknvl@google.com
Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
Reviewed-by: Marco Elver <elver@google.com>
Cc: Alexander Potapenko <glider@google.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Evgenii Stepanov <eugenis@google.com>
Cc: Peter Collingbourne <pcc@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/kasan.h b/include/linux/kasan.h
index b092277..027df75 100644 (file)
--- a/include/linux/kasan.h
+++ b/include/linux/kasan.h
@@ -150,14 +150,6 @@ static __always_inline void kasan_cache_create_kmalloc(struct kmem_cache *cache)
                __kasan_cache_create_kmalloc(cache);
 }
 
-size_t __kasan_metadata_size(struct kmem_cache *cache);
-static __always_inline size_t kasan_metadata_size(struct kmem_cache *cache)
-{
-       if (kasan_enabled())
-               return __kasan_metadata_size(cache);
-       return 0;
-}
-
 void __kasan_poison_slab(struct slab *slab);
 static __always_inline void kasan_poison_slab(struct slab *slab)
 {
@@ -282,7 +274,6 @@ static inline void kasan_cache_create(struct kmem_cache *cache,
                                      unsigned int *size,
                                      slab_flags_t *flags) {}
 static inline void kasan_cache_create_kmalloc(struct kmem_cache *cache) {}
-static inline size_t kasan_metadata_size(struct kmem_cache *cache) { return 0; }
 static inline void kasan_poison_slab(struct slab *slab) {}
 static inline void kasan_unpoison_object_data(struct kmem_cache *cache,
                                        void *object) {}
@@ -333,6 +324,8 @@ static inline void kasan_unpoison_task_stack(struct task_struct *task) {}
 
 #ifdef CONFIG_KASAN_GENERIC
 
+size_t kasan_metadata_size(struct kmem_cache *cache);
+
 void kasan_cache_shrink(struct kmem_cache *cache);
 void kasan_cache_shutdown(struct kmem_cache *cache);
 void kasan_record_aux_stack(void *ptr);
@@ -340,6 +333,12 @@ void kasan_record_aux_stack_noalloc(void *ptr);
 
 #else /* CONFIG_KASAN_GENERIC */
 
+/* Tag-based KASAN modes do not use per-object metadata. */
+static inline size_t kasan_metadata_size(struct kmem_cache *cache)
+{
+       return 0;
+}
+
 static inline void kasan_cache_shrink(struct kmem_cache *cache) {}
 static inline void kasan_cache_shutdown(struct kmem_cache *cache) {}
 static inline void kasan_record_aux_stack(void *ptr) {}

diff --git a/mm/kasan/common.c b/mm/kasan/common.c
index b6a74fe..7c79c56 100644 (file)
--- a/mm/kasan/common.c
+++ b/mm/kasan/common.c
@@ -139,17 +139,6 @@ void __kasan_cache_create_kmalloc(struct kmem_cache *cache)
        cache->kasan_info.is_kmalloc = true;
 }
 
-size_t __kasan_metadata_size(struct kmem_cache *cache)
-{
-       if (!kasan_requires_meta())
-               return 0;
-       return (cache->kasan_info.alloc_meta_offset ?
-               sizeof(struct kasan_alloc_meta) : 0) +
-               ((cache->kasan_info.free_meta_offset &&
-                 cache->kasan_info.free_meta_offset != KASAN_NO_FREE_META) ?
-                sizeof(struct kasan_free_meta) : 0);
-}
-
 void __kasan_poison_slab(struct slab *slab)
 {
        struct page *page = slab_page(slab);

diff --git a/mm/kasan/generic.c b/mm/kasan/generic.c
index 5125fad..806ab92 100644 (file)
--- a/mm/kasan/generic.c
+++ b/mm/kasan/generic.c
@@ -427,6 +427,17 @@ void kasan_init_object_meta(struct kmem_cache *cache, const void *object)
                __memset(alloc_meta, 0, sizeof(*alloc_meta));
 }
 
+size_t kasan_metadata_size(struct kmem_cache *cache)
+{
+       if (!kasan_requires_meta())
+               return 0;
+       return (cache->kasan_info.alloc_meta_offset ?
+               sizeof(struct kasan_alloc_meta) : 0) +
+               ((cache->kasan_info.free_meta_offset &&
+                 cache->kasan_info.free_meta_offset != KASAN_NO_FREE_META) ?
+                sizeof(struct kasan_free_meta) : 0);
+}
+
 static void __kasan_record_aux_stack(void *addr, bool can_alloc)
 {
        struct slab *slab = kasan_addr_to_slab(addr);