zsmalloc: remove zs_compact_control

__zs_compact always putback src_zspage into class list after
migrate_zspage.  Thus, we don't need to keep last position of src_zspage
any more.  Let's remove it.

Link: https://lkml.kernel.org/r/20230624053120.643409-4-senozhatsky@chromium.orgSigned-off-by: Minchan Kim <minchan@kernel.org>
Signed-off-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Acked-by: Sergey Senozhatsky <senozhatsky@chromium.org>
Cc: Alexey Romanov <avromanov@sberdevices.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/zsmalloc.c

@@ -1590,25 +1590,14 @@ static unsigned long find_alloced_obj(struct size_class *class,
 	return find_tagged_obj(class, page, obj_idx, OBJ_ALLOCATED_TAG);
 }
 
-struct zs_compact_control {
-	/* Source spage for migration which could be a subpage of zspage */
-	struct page *s_page;
-	/* Destination page for migration which should be a first page
-	 * of zspage. */
-	struct page *d_page;
-	 /* Starting object index within @s_page which used for live object
-	  * in the subpage. */
-	int obj_idx;
-};
-
-static void migrate_zspage(struct zs_pool *pool, struct size_class *class,
-			   struct zs_compact_control *cc)
+static void migrate_zspage(struct zs_pool *pool, struct zspage *src_zspage,
+			   struct zspage *dst_zspage)
 {
 	unsigned long used_obj, free_obj;
 	unsigned long handle;
-	struct page *s_page = cc->s_page;
-	struct page *d_page = cc->d_page;
-	int obj_idx = cc->obj_idx;
+	int obj_idx = 0;
+	struct page *s_page = get_first_page(src_zspage);
+	struct size_class *class = pool->size_class[src_zspage->class];
 
 	while (1) {
 		handle = find_alloced_obj(class, s_page, &obj_idx);
@@ -1621,24 +1610,20 @@ static void migrate_zspage(struct zs_pool *pool, struct size_class *class,
 		}
 
 		used_obj = handle_to_obj(handle);
-		free_obj = obj_malloc(pool, get_zspage(d_page), handle);
+		free_obj = obj_malloc(pool, dst_zspage, handle);
 		zs_object_copy(class, free_obj, used_obj);
 		obj_idx++;
 		record_obj(handle, free_obj);
 		obj_free(class->size, used_obj);
 
 		/* Stop if there is no more space */
-		if (zspage_full(class, get_zspage(d_page)))
+		if (zspage_full(class, dst_zspage))
 			break;
 
 		/* Stop if there are no more objects to migrate */
-		if (zspage_empty(get_zspage(s_page)))
+		if (zspage_empty(src_zspage))
 			break;
 	}
-
-	/* Remember last position in this iteration */
-	cc->s_page = s_page;
-	cc->obj_idx = obj_idx;
 }
 
 static struct zspage *isolate_src_zspage(struct size_class *class)
@@ -2013,7 +1998,6 @@ static unsigned long zs_can_compact(struct size_class *class)
 static unsigned long __zs_compact(struct zs_pool *pool,
 				  struct size_class *class)
 {
-	struct zs_compact_control cc;
 	struct zspage *src_zspage = NULL;
 	struct zspage *dst_zspage = NULL;
 	unsigned long pages_freed = 0;
@@ -2031,7 +2015,6 @@ static unsigned long __zs_compact(struct zs_pool *pool,
 			if (!dst_zspage)
 				break;
 			migrate_write_lock(dst_zspage);
-			cc.d_page = get_first_page(dst_zspage);
 		}
 
 		src_zspage = isolate_src_zspage(class);
@@ -2040,9 +2023,7 @@ static unsigned long __zs_compact(struct zs_pool *pool,
 
 		migrate_write_lock_nested(src_zspage);
 
-		cc.obj_idx = 0;
-		cc.s_page = get_first_page(src_zspage);
-		migrate_zspage(pool, class, &cc);
+		migrate_zspage(pool, src_zspage, dst_zspage);
 		fg = putback_zspage(class, src_zspage);
 		migrate_write_unlock(src_zspage);