[PATCH v5 06/16] hashtable: add macro HASHTABLE_INIT

[Changyuan Lyu <changyuanl@google.com>]

Similar to HLIST_HEAD_INIT, HASHTABLE_INIT allows a hashtable embedded
in another structure to be initialized at compile time.

Example,

struct tree_node {
    DECLARE_HASHTABLE(properties, 4);
    DECLARE_HASHTABLE(sub_nodes, 4);
};

static struct tree_node root_node = {
    .properties = HASHTABLE_INIT(4),
    .sub_nodes = HASHTABLE_INIT(4),
};

Signed-off-by: Changyuan Lyu <changyuanl@google.com>
---
 include/linux/hashtable.h | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

diff --git a/include/linux/hashtable.h b/include/linux/hashtable.h
index f6c666730b8c..27e07a436e2a 100644
--- a/include/linux/hashtable.h
+++ b/include/linux/hashtable.h
@@ -13,13 +13,14 @@
 #include <linux/hash.h>
 #include <linux/rculist.h>
 
+#define HASHTABLE_INIT(bits) { [0 ... ((1 << (bits)) - 1)] = HLIST_HEAD_INIT }
+
 #define DEFINE_HASHTABLE(name, bits)						\
-	struct hlist_head name[1 << (bits)] =					\
-			{ [0 ... ((1 << (bits)) - 1)] = HLIST_HEAD_INIT }
+	struct hlist_head name[1 << (bits)] =	HASHTABLE_INIT(bits)	\
 
 #define DEFINE_READ_MOSTLY_HASHTABLE(name, bits)				\
 	struct hlist_head name[1 << (bits)] __read_mostly =			\
-			{ [0 ... ((1 << (bits)) - 1)] = HLIST_HEAD_INIT }
+		HASHTABLE_INIT(bits)
 
 #define DECLARE_HASHTABLE(name, bits)                                   	\
 	struct hlist_head name[1 << (bits)]
-- 
2.48.1.711.g2feabab25a-goog