Revert "ANDROID: mm: add get_each_object_track function"

This reverts commit 1fb8e678a5.

It causes build errors in 5.15-rc1 and there are no in-kernel users of
this api so remove it.  If it is needed, someone can easily add a
working version of it back.

Bug: 177377077
Cc: Vijayanand Jitta <vjitta@codeaurora.org>
Cc: Palmer Dabbelt <palmerdabbelt@google.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@google.com>
Change-Id: I74fe57124b74e9695636d139b1f548b69fbc9039

mm/slab.h

@@ -91,24 +91,6 @@ struct kmem_cache *kmalloc_slab(size_t, gfp_t);
 
 gfp_t kmalloc_fix_flags(gfp_t flags);
 
-#ifdef CONFIG_SLUB
-/*
- * Tracking user of a slab.
- */
-#define TRACK_ADDRS_COUNT 16
-struct track {
-	unsigned long addr;	/* Called from address */
-#ifdef CONFIG_STACKTRACE
-	unsigned long addrs[TRACK_ADDRS_COUNT]; /* Called from address */
-#endif
-	int cpu;		/* Was running on cpu */
-	int pid;		/* Pid context */
-	unsigned long when;	/* When did the operation occur */
-};
-
-enum track_item { TRACK_ALLOC, TRACK_FREE };
-#endif
-
 /* Functions provided by the slab allocators */
 int __kmem_cache_create(struct kmem_cache *, slab_flags_t flags);
 
@@ -234,10 +216,6 @@ DECLARE_STATIC_KEY_FALSE(slub_debug_enabled);
 #endif
 extern void print_tracking(struct kmem_cache *s, void *object);
 long validate_slab_cache(struct kmem_cache *s);
-extern unsigned long get_each_object_track(struct kmem_cache *s,
-		struct page *page, enum track_item alloc,
-		int (*fn)(const struct kmem_cache *, const void *,
-		const struct track *, void *), void *private);
 static inline bool __slub_debug_enabled(void)
 {
 	return static_branch_unlikely(&slub_debug_enabled);
@@ -246,15 +224,6 @@ static inline bool __slub_debug_enabled(void)
 static inline void print_tracking(struct kmem_cache *s, void *object)
 {
 }
-#ifdef CONFIG_SLUB
-static inline unsigned long get_each_object_track(struct kmem_cache *s,
-		struct page *page, enum track_item alloc,
-		int (*fn)(const struct kmem_cache *, const void *,
-		const struct track *, void *), void *private)
-{
-	return 0;
-}
-#endif
 static inline bool __slub_debug_enabled(void)
 {
 	return false;

mm/slub.c

@@ -200,6 +200,22 @@ static inline bool kmem_cache_has_cpu_partial(struct kmem_cache *s)
 /* Use cmpxchg_double */
 #define __CMPXCHG_DOUBLE	((slab_flags_t __force)0x40000000U)
 
+/*
+ * Tracking user of a slab.
+ */
+#define TRACK_ADDRS_COUNT 16
+struct track {
+	unsigned long addr;	/* Called from address */
+#ifdef CONFIG_STACKTRACE
+	unsigned long addrs[TRACK_ADDRS_COUNT];	/* Called from address */
+#endif
+	int cpu;		/* Was running on cpu */
+	int pid;		/* Pid context */
+	unsigned long when;	/* When did the operation occur */
+};
+
+enum track_item { TRACK_ALLOC, TRACK_FREE };
+
 #ifdef CONFIG_SYSFS
 static int sysfs_slab_add(struct kmem_cache *);
 static int sysfs_slab_alias(struct kmem_cache *, const char *);
@@ -595,39 +611,6 @@ static struct track *get_track(struct kmem_cache *s, void *object,
 	return kasan_reset_tag(p + alloc);
 }
 
-/*
- * This function will be used to loop through all the slab objects in
- * a page to give track structure for each object, the function fn will
- * be using this track structure and extract required info into its private
- * data, the return value will be the number of track structures that are
- * processed.
- */
-unsigned long get_each_object_track(struct kmem_cache *s,
-		struct page *page, enum track_item alloc,
-		int (*fn)(const struct kmem_cache *, const void *,
-		const struct track *, void *), void *private)
-{
-	void *p;
-	struct track *t;
-	int ret;
-	unsigned long num_track = 0;
-
-	if (!slub_debug || !(s->flags & SLAB_STORE_USER))
-		return 0;
-
-	slab_lock(page);
-	for_each_object(p, s, page_address(page), page->objects) {
-		t = get_track(s, p, alloc);
-		ret = fn(s, p, t, private);
-		if (ret < 0)
-			break;
-		num_track += 1;
-	}
-	slab_unlock(page);
-	return num_track;
-}
-EXPORT_SYMBOL_GPL(get_each_object_track);
-
 static void set_track(struct kmem_cache *s, void *object,
 			enum track_item alloc, unsigned long addr)
 {