ofp-actions: Factor OFPACT_PADDED_MEMBERS out into a more general form.

This makes it easier to reuse this idea elsewhere. Signed-off-by: Ben Pfaff <[email protected]> Acked-by: Ryan Moats <[email protected]>
water0615 · Aug 8, 2016 · 7b51295 · 7b51295
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commit 7b51295
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Showing 2 changed files with 22 additions and 14 deletions.
diff --git a/include/openvswitch/ofp-actions.h b/include/openvswitch/ofp-actions.h
@@ -185,19 +185,7 @@ BUILD_ASSERT_DECL(sizeof(struct ofpact) == 4);
 /* Alignment. */
 #define OFPACT_ALIGNTO 8
 #define OFPACT_ALIGN(SIZE) ROUND_UP(SIZE, OFPACT_ALIGNTO)
-
-/* Expands to an anonymous union that contains:
- *
- *    - MEMBERS in a nested anonymous struct.
- *
- *    - An array as large as MEMBERS plus padding to a multiple of 8 bytes.
- *
- * The effect is to pad MEMBERS to a multiple of 8 bytes. */
-#define OFPACT_PADDED_MEMBERS(MEMBERS)                          \
-    union {                                                     \
-        struct { MEMBERS };                                     \
-        uint8_t pad[OFPACT_ALIGN(sizeof(struct { MEMBERS }))];  \
-    }
+#define OFPACT_PADDED_MEMBERS(MEMBERS) PADDED_MEMBERS(OFPACT_ALIGNTO, MEMBERS)
 
 /* Returns the ofpact following 'ofpact'. */
 static inline struct ofpact *

diff --git a/include/openvswitch/util.h b/include/openvswitch/util.h
@@ -1,5 +1,5 @@
 /*
- * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014 Nicira, Inc.
+ * Copyright (c) 2008, 2009, 2010, 2011, 2012, 2013, 2014, 2016 Nicira, Inc.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -162,6 +162,26 @@ OVS_NO_RETURN void ovs_assert_failure(const char *, const char *, const char *);
 /* Returns true if X is a power of 2, otherwise false. */
 #define IS_POW2(X) ((X) && !((X) & ((X) - 1)))
 
+/* Expands to an anonymous union that contains:
+ *
+ *    - MEMBERS in a nested anonymous struct.
+ *
+ *    - An array as large as MEMBERS plus padding to a multiple of UNIT bytes.
+ *
+ * The effect is to pad MEMBERS to a multiple of UNIT bytes.
+ *
+ * For example, the struct below is 8 bytes long, with 6 bytes of padding:
+ *
+ *     struct padded_struct {
+ *         PADDED_MEMBERS(8, uint8_t x; uint8_t y;);
+ *     };
+ */
+#define PADDED_MEMBERS(UNIT, MEMBERS)                               \
+    union {                                                         \
+        struct { MEMBERS };                                         \
+        uint8_t pad[ROUND_UP(sizeof(struct { MEMBERS }), UNIT)];    \
+    }
+
 static inline bool
 is_pow2(uintmax_t x)
 {