diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index b8b098be92fa..5d4c4d254679 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -30,6 +30,14 @@
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
 
+/*
+ * lock ordering:
+ *	page_lock
+ *	pool->migrate_lock
+ *	class->lock
+ *	zspage->lock
+ */
+
 #include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/sched.h>
@@ -100,15 +108,6 @@
 
 #define _PFN_BITS		(MAX_POSSIBLE_PHYSMEM_BITS - PAGE_SHIFT)
 
-/*
- * Memory for allocating for handle keeps object position by
- * encoding <page, obj_idx> and the encoded value has a room
- * in least bit(ie, look at obj_to_location).
- * We use the bit to synchronize between object access by
- * user and migration.
- */
-#define HANDLE_PIN_BIT	0
-
 /*
  * Head in allocated object should have OBJ_ALLOCATED_TAG
  * to identify the object was allocated or not.
@@ -255,6 +254,8 @@ struct zs_pool {
 	struct inode *inode;
 	struct work_struct free_work;
 #endif
+	/* protect page/zspage migration */
+	rwlock_t migrate_lock;
 };
 
 struct zspage {
@@ -297,6 +298,9 @@ static void zs_unregister_migration(struct zs_pool *pool);
 static void migrate_lock_init(struct zspage *zspage);
 static void migrate_read_lock(struct zspage *zspage);
 static void migrate_read_unlock(struct zspage *zspage);
+static void migrate_write_lock(struct zspage *zspage);
+static void migrate_write_lock_nested(struct zspage *zspage);
+static void migrate_write_unlock(struct zspage *zspage);
 static void kick_deferred_free(struct zs_pool *pool);
 static void init_deferred_free(struct zs_pool *pool);
 static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage);
@@ -308,6 +312,9 @@ static void zs_unregister_migration(struct zs_pool *pool) {}
 static void migrate_lock_init(struct zspage *zspage) {}
 static void migrate_read_lock(struct zspage *zspage) {}
 static void migrate_read_unlock(struct zspage *zspage) {}
+static void migrate_write_lock(struct zspage *zspage) {}
+static void migrate_write_lock_nested(struct zspage *zspage) {}
+static void migrate_write_unlock(struct zspage *zspage) {}
 static void kick_deferred_free(struct zs_pool *pool) {}
 static void init_deferred_free(struct zs_pool *pool) {}
 static void SetZsPageMovable(struct zs_pool *pool, struct zspage *zspage) {}
@@ -359,14 +366,10 @@ static void cache_free_zspage(struct zs_pool *pool, struct zspage *zspage)
 	kmem_cache_free(pool->zspage_cachep, zspage);
 }
 
+/* class->lock(which owns the handle) synchronizes races */
 static void record_obj(unsigned long handle, unsigned long obj)
 {
-	/*
-	 * lsb of @obj represents handle lock while other bits
-	 * represent object value the handle is pointing so
-	 * updating shouldn't do store tearing.
-	 */
-	WRITE_ONCE(*(unsigned long *)handle, obj);
+	*(unsigned long *)handle = obj;
 }
 
 /* zpool driver */
@@ -880,26 +883,6 @@ static bool obj_allocated(struct page *page, void *obj, unsigned long *phandle)
 	return true;
 }
 
-static inline int testpin_tag(unsigned long handle)
-{
-	return bit_spin_is_locked(HANDLE_PIN_BIT, (unsigned long *)handle);
-}
-
-static inline int trypin_tag(unsigned long handle)
-{
-	return bit_spin_trylock(HANDLE_PIN_BIT, (unsigned long *)handle);
-}
-
-static void pin_tag(unsigned long handle) __acquires(bitlock)
-{
-	bit_spin_lock(HANDLE_PIN_BIT, (unsigned long *)handle);
-}
-
-static void unpin_tag(unsigned long handle) __releases(bitlock)
-{
-	bit_spin_unlock(HANDLE_PIN_BIT, (unsigned long *)handle);
-}
-
 static void reset_page(struct page *page)
 {
 	__ClearPageMovable(page);
@@ -968,6 +951,11 @@ static void free_zspage(struct zs_pool *pool, struct size_class *class,
 	VM_BUG_ON(get_zspage_inuse(zspage));
 	VM_BUG_ON(list_empty(&zspage->list));
 
+	/*
+	 * Since zs_free couldn't be sleepable, this function cannot call
+	 * lock_page. The page locks trylock_zspage got will be released
+	 * by __free_zspage.
+	 */
 	if (!trylock_zspage(zspage)) {
 		kick_deferred_free(pool);
 		return;
@@ -1263,15 +1251,20 @@ void *zs_map_object(struct zs_pool *pool, unsigned long handle,
 	 */
 	BUG_ON(in_interrupt());
 
-	/* From now on, migration cannot move the object */
-	pin_tag(handle);
-
+	/* It guarantees it can get zspage from handle safely */
+	read_lock(&pool->migrate_lock);
 	obj = handle_to_obj(handle);
 	obj_to_location(obj, &page, &obj_idx);
 	zspage = get_zspage(page);
 
-	/* migration cannot move any subpage in this zspage */
+	/*
+	 * migration cannot move any zpages in this zspage. Here, class->lock
+	 * is too heavy since callers would take some time until they calls
+	 * zs_unmap_object API so delegate the locking from class to zspage
+	 * which is smaller granularity.
+	 */
 	migrate_read_lock(zspage);
+	read_unlock(&pool->migrate_lock);
 
 	class = zspage_class(pool, zspage);
 	off = (class->size * obj_idx) & ~PAGE_MASK;
@@ -1330,7 +1323,6 @@ void zs_unmap_object(struct zs_pool *pool, unsigned long handle)
 	put_cpu_var(zs_map_area);
 
 	migrate_read_unlock(zspage);
-	unpin_tag(handle);
 }
 EXPORT_SYMBOL_GPL(zs_unmap_object);
 
@@ -1424,6 +1416,7 @@ unsigned long zs_malloc(struct zs_pool *pool, size_t size, gfp_t gfp)
 	size += ZS_HANDLE_SIZE;
 	class = pool->size_class[get_size_class_index(size)];
 
+	/* class->lock effectively protects the zpage migration */
 	spin_lock(&class->lock);
 	zspage = find_get_zspage(class);
 	if (likely(zspage)) {
@@ -1501,30 +1494,27 @@ void zs_free(struct zs_pool *pool, unsigned long handle)
 	if (unlikely(!handle))
 		return;
 
-	pin_tag(handle);
+	/*
+	 * The pool->migrate_lock protects the race with zpage's migration
+	 * so it's safe to get the page from handle.
+	 */
+	read_lock(&pool->migrate_lock);
 	obj = handle_to_obj(handle);
 	obj_to_page(obj, &f_page);
 	zspage = get_zspage(f_page);
-
-	migrate_read_lock(zspage);
 	class = zspage_class(pool, zspage);
-
 	spin_lock(&class->lock);
+	read_unlock(&pool->migrate_lock);
+
 	obj_free(class->size, obj);
 	class_stat_dec(class, OBJ_USED, 1);
 	fullness = fix_fullness_group(class, zspage);
-	if (fullness != ZS_EMPTY) {
-		migrate_read_unlock(zspage);
+	if (fullness != ZS_EMPTY)
 		goto out;
-	}
 
-	migrate_read_unlock(zspage);
-	/* If zspage is isolated, zs_page_putback will free the zspage */
 	free_zspage(pool, class, zspage);
 out:
-
 	spin_unlock(&class->lock);
-	unpin_tag(handle);
 	cache_free_handle(pool, handle);
 }
 EXPORT_SYMBOL_GPL(zs_free);
@@ -1608,11 +1598,8 @@ static unsigned long find_alloced_obj(struct size_class *class,
 	offset += class->size * index;
 
 	while (offset < PAGE_SIZE) {
-		if (obj_allocated(page, addr + offset, &handle)) {
-			if (trypin_tag(handle))
-				break;
-			handle = 0;
-		}
+		if (obj_allocated(page, addr + offset, &handle))
+			break;
 
 		offset += class->size;
 		index++;
@@ -1658,7 +1645,6 @@ static int migrate_zspage(struct zs_pool *pool, struct size_class *class,
 
 		/* Stop if there is no more space */
 		if (zspage_full(class, get_zspage(d_page))) {
-			unpin_tag(handle);
 			ret = -ENOMEM;
 			break;
 		}
@@ -1667,15 +1653,7 @@ static int migrate_zspage(struct zs_pool *pool, struct size_class *class,
 		free_obj = obj_malloc(pool, get_zspage(d_page), handle);
 		zs_object_copy(class, free_obj, used_obj);
 		obj_idx++;
-		/*
-		 * record_obj updates handle's value to free_obj and it will
-		 * invalidate lock bit(ie, HANDLE_PIN_BIT) of handle, which
-		 * breaks synchronization using pin_tag(e,g, zs_free) so
-		 * let's keep the lock bit.
-		 */
-		free_obj |= BIT(HANDLE_PIN_BIT);
 		record_obj(handle, free_obj);
-		unpin_tag(handle);
 		obj_free(class->size, used_obj);
 	}
 
@@ -1789,6 +1767,11 @@ static void migrate_write_lock(struct zspage *zspage)
 	write_lock(&zspage->lock);
 }
 
+static void migrate_write_lock_nested(struct zspage *zspage)
+{
+	write_lock_nested(&zspage->lock, SINGLE_DEPTH_NESTING);
+}
+
 static void migrate_write_unlock(struct zspage *zspage)
 {
 	write_unlock(&zspage->lock);
@@ -1856,11 +1839,10 @@ static int zs_page_migrate(struct address_space *mapping, struct page *newpage,
 	struct zspage *zspage;
 	struct page *dummy;
 	void *s_addr, *d_addr, *addr;
-	int offset, pos;
+	int offset;
 	unsigned long handle;
 	unsigned long old_obj, new_obj;
 	unsigned int obj_idx;
-	int ret = -EAGAIN;
 
 	/*
 	 * We cannot support the _NO_COPY case here, because copy needs to
@@ -1873,32 +1855,25 @@ static int zs_page_migrate(struct address_space *mapping, struct page *newpage,
 	VM_BUG_ON_PAGE(!PageMovable(page), page);
 	VM_BUG_ON_PAGE(!PageIsolated(page), page);
 
-	zspage = get_zspage(page);
-
-	/* Concurrent compactor cannot migrate any subpage in zspage */
-	migrate_write_lock(zspage);
 	pool = mapping->private_data;
+
+	/*
+	 * The pool migrate_lock protects the race between zpage migration
+	 * and zs_free.
+	 */
+	write_lock(&pool->migrate_lock);
+	zspage = get_zspage(page);
 	class = zspage_class(pool, zspage);
-	offset = get_first_obj_offset(page);
 
+	/*
+	 * the class lock protects zpage alloc/free in the zspage.
+	 */
 	spin_lock(&class->lock);
-	if (!get_zspage_inuse(zspage)) {
-		/*
-		 * Set "offset" to end of the page so that every loops
-		 * skips unnecessary object scanning.
-		 */
-		offset = PAGE_SIZE;
-	}
+	/* the migrate_write_lock protects zpage access via zs_map_object */
+	migrate_write_lock(zspage);
 
-	pos = offset;
+	offset = get_first_obj_offset(page);
 	s_addr = kmap_atomic(page);
-	while (pos < PAGE_SIZE) {
-		if (obj_allocated(page, s_addr + pos, &handle)) {
-			if (!trypin_tag(handle))
-				goto unpin_objects;
-		}
-		pos += class->size;
-	}
 
 	/*
 	 * Here, any user cannot access all objects in the zspage so let's move.
@@ -1907,25 +1882,30 @@ static int zs_page_migrate(struct address_space *mapping, struct page *newpage,
 	memcpy(d_addr, s_addr, PAGE_SIZE);
 	kunmap_atomic(d_addr);
 
-	for (addr = s_addr + offset; addr < s_addr + pos;
+	for (addr = s_addr + offset; addr < s_addr + PAGE_SIZE;
 					addr += class->size) {
 		if (obj_allocated(page, addr, &handle)) {
-			BUG_ON(!testpin_tag(handle));
 
 			old_obj = handle_to_obj(handle);
 			obj_to_location(old_obj, &dummy, &obj_idx);
 			new_obj = (unsigned long)location_to_obj(newpage,
 								obj_idx);
-			new_obj |= BIT(HANDLE_PIN_BIT);
 			record_obj(handle, new_obj);
 		}
 	}
+	kunmap_atomic(s_addr);
 
 	replace_sub_page(class, zspage, newpage, page);
-	get_page(newpage);
-
+	/*
+	 * Since we complete the data copy and set up new zspage structure,
+	 * it's okay to release migration_lock.
+	 */
+	write_unlock(&pool->migrate_lock);
+	spin_unlock(&class->lock);
 	dec_zspage_isolation(zspage);
+	migrate_write_unlock(zspage);
 
+	get_page(newpage);
 	if (page_zone(newpage) != page_zone(page)) {
 		dec_zone_page_state(page, NR_ZSPAGES);
 		inc_zone_page_state(newpage, NR_ZSPAGES);
@@ -1933,22 +1913,8 @@ static int zs_page_migrate(struct address_space *mapping, struct page *newpage,
 
 	reset_page(page);
 	put_page(page);
-	page = newpage;
-
-	ret = MIGRATEPAGE_SUCCESS;
-unpin_objects:
-	for (addr = s_addr + offset; addr < s_addr + pos;
-						addr += class->size) {
-		if (obj_allocated(page, addr, &handle)) {
-			BUG_ON(!testpin_tag(handle));
-			unpin_tag(handle);
-		}
-	}
-	kunmap_atomic(s_addr);
-	spin_unlock(&class->lock);
-	migrate_write_unlock(zspage);
 
-	return ret;
+	return MIGRATEPAGE_SUCCESS;
 }
 
 static void zs_page_putback(struct page *page)
@@ -2077,8 +2043,13 @@ static unsigned long __zs_compact(struct zs_pool *pool,
 	struct zspage *dst_zspage = NULL;
 	unsigned long pages_freed = 0;
 
+	/* protect the race between zpage migration and zs_free */
+	write_lock(&pool->migrate_lock);
+	/* protect zpage allocation/free */
 	spin_lock(&class->lock);
 	while ((src_zspage = isolate_zspage(class, true))) {
+		/* protect someone accessing the zspage(i.e., zs_map_object) */
+		migrate_write_lock(src_zspage);
 
 		if (!zs_can_compact(class))
 			break;
@@ -2087,6 +2058,8 @@ static unsigned long __zs_compact(struct zs_pool *pool,
 		cc.s_page = get_first_page(src_zspage);
 
 		while ((dst_zspage = isolate_zspage(class, false))) {
+			migrate_write_lock_nested(dst_zspage);
+
 			cc.d_page = get_first_page(dst_zspage);
 			/*
 			 * If there is no more space in dst_page, resched
@@ -2096,6 +2069,10 @@ static unsigned long __zs_compact(struct zs_pool *pool,
 				break;
 
 			putback_zspage(class, dst_zspage);
+			migrate_write_unlock(dst_zspage);
+			dst_zspage = NULL;
+			if (rwlock_is_contended(&pool->migrate_lock))
+				break;
 		}
 
 		/* Stop if we couldn't find slot */
@@ -2103,19 +2080,28 @@ static unsigned long __zs_compact(struct zs_pool *pool,
 			break;
 
 		putback_zspage(class, dst_zspage);
+		migrate_write_unlock(dst_zspage);
+
 		if (putback_zspage(class, src_zspage) == ZS_EMPTY) {
+			migrate_write_unlock(src_zspage);
 			free_zspage(pool, class, src_zspage);
 			pages_freed += class->pages_per_zspage;
-		}
+		} else
+			migrate_write_unlock(src_zspage);
 		spin_unlock(&class->lock);
+		write_unlock(&pool->migrate_lock);
 		cond_resched();
+		write_lock(&pool->migrate_lock);
 		spin_lock(&class->lock);
 	}
 
-	if (src_zspage)
+	if (src_zspage) {
 		putback_zspage(class, src_zspage);
+		migrate_write_unlock(src_zspage);
+	}
 
 	spin_unlock(&class->lock);
+	write_unlock(&pool->migrate_lock);
 
 	return pages_freed;
 }
@@ -2221,6 +2207,7 @@ struct zs_pool *zs_create_pool(const char *name)
 		return NULL;
 
 	init_deferred_free(pool);
+	rwlock_init(&pool->migrate_lock);
 
 	pool->name = kstrdup(name, GFP_KERNEL);
 	if (!pool->name)
