[PATCH V2 1/2] zpool: Add malloc_support_movable to zpool_driver

[Hui Zhu <teawaterz@xxxxxxxxxxxxxxxxx>]

As a zpool_driver, zsmalloc can allocate movable memory because it
support migate pages.
But zbud and z3fold cannot allocate movable memory.

This commit adds malloc_support_movable to zpool_driver.
If a zpool_driver support allocate movable memory, set it to true.
And add zpool_malloc_support_movable check malloc_support_movable
to make sure if a zpool support allocate movable memory.

Signed-off-by: Hui Zhu <teawaterz@xxxxxxxxxxxxxxxxx>
---
 include/linux/zpool.h |  3 +++
 mm/zpool.c            | 16 ++++++++++++++++
 mm/zsmalloc.c         | 19 ++++++++++---------
 3 files changed, 29 insertions(+), 9 deletions(-)

diff --git a/include/linux/zpool.h b/include/linux/zpool.h
index 7238865e75b0..51bf43076165 100644
--- a/include/linux/zpool.h
+++ b/include/linux/zpool.h
@@ -46,6 +46,8 @@ const char *zpool_get_type(struct zpool *pool);
 
 void zpool_destroy_pool(struct zpool *pool);
 
+bool zpool_malloc_support_movable(struct zpool *pool);
+
 int zpool_malloc(struct zpool *pool, size_t size, gfp_t gfp,
 			unsigned long *handle);
 
@@ -90,6 +92,7 @@ struct zpool_driver {
 			struct zpool *zpool);
 	void (*destroy)(void *pool);
 
+	bool malloc_support_movable;
 	int (*malloc)(void *pool, size_t size, gfp_t gfp,
 				unsigned long *handle);
 	void (*free)(void *pool, unsigned long handle);
diff --git a/mm/zpool.c b/mm/zpool.c
index a2dd9107857d..863669212070 100644
--- a/mm/zpool.c
+++ b/mm/zpool.c
@@ -238,6 +238,22 @@ const char *zpool_get_type(struct zpool *zpool)
 	return zpool->driver->type;
 }
 
+/**
+ * zpool_malloc_support_movable() - Check if the zpool support
+ * allocate movable memory
+ * @zpool:	The zpool to check
+ *
+ * This returns if the zpool support allocate movable memory.
+ *
+ * Implementations must guarantee this to be thread-safe.
+ *
+ * Returns: true if if the zpool support allocate movable memory, false if not
+ */
+bool zpool_malloc_support_movable(struct zpool *zpool)
+{
+	return zpool->driver->malloc_support_movable;
+}
+
 /**
  * zpool_malloc() - Allocate memory
  * @zpool:	The zpool to allocate from.
diff --git a/mm/zsmalloc.c b/mm/zsmalloc.c
index 0787d33b80d8..8f3d9a4d46f4 100644
--- a/mm/zsmalloc.c
+++ b/mm/zsmalloc.c
@@ -437,15 +437,16 @@ static u64 zs_zpool_total_size(void *pool)
 }
 
 static struct zpool_driver zs_zpool_driver = {
-	.type =		"zsmalloc",
-	.owner =	THIS_MODULE,
-	.create =	zs_zpool_create,
-	.destroy =	zs_zpool_destroy,
-	.malloc =	zs_zpool_malloc,
-	.free =		zs_zpool_free,
-	.map =		zs_zpool_map,
-	.unmap =	zs_zpool_unmap,
-	.total_size =	zs_zpool_total_size,
+	.type =			  "zsmalloc",
+	.owner =		  THIS_MODULE,
+	.create =		  zs_zpool_create,
+	.destroy =		  zs_zpool_destroy,
+	.malloc_support_movable = true,
+	.malloc =		  zs_zpool_malloc,
+	.free =			  zs_zpool_free,
+	.map =			  zs_zpool_map,
+	.unmap =		  zs_zpool_unmap,
+	.total_size =		  zs_zpool_total_size,
 };
 
 MODULE_ALIAS("zpool-zsmalloc");
-- 
2.20.1 (Apple Git-117)