kasan: clear metadata functions for tag-based modes

Remove implementations of the metadata-related functions for the tag-based
modes.

The following patches in the series will provide alternative
implementations.

As of this patch, the tag-based modes no longer collect alloc and free
stack traces.  This functionality will be restored later in the series.

Link: https://lkml.kernel.org/r/470fbe5d15e8015092e76e395de354be18ccceab.1662411799.git.andreyknvl@google.comSigned-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>

mm/kasan/tags.c

@@ -19,54 +19,25 @@
 
 void kasan_init_object_meta(struct kmem_cache *cache, const void *object)
 {
-	struct kasan_alloc_meta *alloc_meta;
-
-	alloc_meta = kasan_get_alloc_meta(cache, object);
-	if (alloc_meta)
-		__memset(alloc_meta, 0, sizeof(*alloc_meta));
 }
 
 void kasan_save_alloc_info(struct kmem_cache *cache, void *object, gfp_t flags)
 {
-	struct kasan_alloc_meta *alloc_meta;
-
-	alloc_meta = kasan_get_alloc_meta(cache, object);
-	if (alloc_meta)
-		kasan_set_track(&alloc_meta->alloc_track, flags);
 }
 
 void kasan_save_free_info(struct kmem_cache *cache,
 				void *object, u8 tag)
 {
-	struct kasan_alloc_meta *alloc_meta;
-
-	alloc_meta = kasan_get_alloc_meta(cache, object);
-	if (!alloc_meta)
-		return;
-
-	kasan_set_track(&alloc_meta->free_track, GFP_NOWAIT);
 }
 
 struct kasan_track *kasan_get_alloc_track(struct kmem_cache *cache,
 						void *object)
 {
-	struct kasan_alloc_meta *alloc_meta;
-
-	alloc_meta = kasan_get_alloc_meta(cache, object);
-	if (!alloc_meta)
-		return NULL;
-
-	return &alloc_meta->alloc_track;
+	return NULL;
 }
 
 struct kasan_track *kasan_get_free_track(struct kmem_cache *cache,
 						void *object, u8 tag)
 {
-	struct kasan_alloc_meta *alloc_meta;
-
-	alloc_meta = kasan_get_alloc_meta(cache, object);
-	if (!alloc_meta)
-		return NULL;
-
-	return &alloc_meta->free_track;
+	return NULL;
 }