kasan: only define metadata offsets for Generic mode

Hide the definitions of alloc_meta_offset and free_meta_offset under an
ifdef CONFIG_KASAN_GENERIC check, as these fields are now only used when
the Generic mode is enabled.

Link: https://lkml.kernel.org/r/d4bafa0534facafd1a23c465a94261e64f366493.1662411799.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>

include/linux/kasan.h

@@ -98,8 +98,10 @@ static inline bool kasan_has_integrated_init(void)
 #ifdef CONFIG_KASAN
 
 struct kasan_cache {
+#ifdef CONFIG_KASAN_GENERIC
 	int alloc_meta_offset;
 	int free_meta_offset;
+#endif
 	bool is_kmalloc;
 };