+#define KDBUS_ITEM_NEXT(item) \
+ (typeof(item))(((uint8_t *)item) + ALIGN8((item)->size))
+
+#define KDBUS_ITEM_FOREACH(part, head, first) \
+ for (part = (head)->first; \
+ (uint8_t *)(part) < (uint8_t *)(head) + (head)->size; \
+ part = KDBUS_ITEM_NEXT(part))
+
+#define KDBUS_ITEM_HEADER_SIZE offsetof(struct kdbus_item, data)
+#define KDBUS_ITEM_SIZE(s) ALIGN8((s) + KDBUS_ITEM_HEADER_SIZE)
+
+#define MEMFD_CACHE_MAX 32
+
+/* When we cache a memfd block for reuse, we will truncate blocks
+ * longer than this in order not to keep too much data around. */
+#define MEMFD_CACHE_ITEM_SIZE_MAX (128*1024)
+
+/* This determines at which minimum size we prefer sending memfds over
+ * sending vectors */
+#define MEMFD_MIN_SIZE (128*1024)
+
+/* The size of the per-connection memory pool that we set up and where
+ * the kernel places our incoming messages */
+#define KDBUS_POOL_SIZE (16*1024*1024)
+
+struct memfd_cache {
+ int fd;
+ void *address;
+ size_t size;
+};
+