[PATCH v23 1/4] flow: Flow table traversing macros

[David Gibson <david@gibson.dropbear.id.au>]

The migration code adds more places that need to iterate through the flow
table.  Introduce some macros to make that easier.

Signed-off-by: David Gibson <david@gibson.dropbear.id.au>
---
 flow.c       | 14 +++++++-------
 flow_table.h | 31 +++++++++++++++++++++++++++++++
 2 files changed, 38 insertions(+), 7 deletions(-)

diff --git a/flow.c b/flow.c
index 3ac551bd..d9b888ce 100644
--- a/flow.c
+++ b/flow.c
@@ -771,7 +771,7 @@ void flow_defer_handler(const struct ctx *c, const struct timespec *now)
 	struct flow_free_cluster *free_head = NULL;
 	unsigned *last_next = &flow_first_free;
 	bool timer = false;
-	unsigned idx;
+	union flow *flow;
 
 	if (timespec_diff_ms(now, &flow_timer_run) >= FLOW_TIMER_INTERVAL) {
 		timer = true;
@@ -780,8 +780,7 @@ void flow_defer_handler(const struct ctx *c, const struct timespec *now)
 
 	ASSERT(!flow_new_entry); /* Incomplete flow at end of cycle */
 
-	for (idx = 0; idx < FLOW_MAX; idx++) {
-		union flow *flow = &flowtab[idx];
+	flow_foreach_slot(flow) {
 		bool closed = false;
 
 		switch (flow->f.state) {
@@ -798,12 +797,12 @@ void flow_defer_handler(const struct ctx *c, const struct timespec *now)
 			} else {
 				/* New free cluster, add to chain */
 				free_head = &flow->free;
-				*last_next = idx;
+				*last_next = FLOW_IDX(flow);
 				last_next = &free_head->next;
 			}
 
 			/* Skip remaining empty entries */
-			idx += skip - 1;
+			flow += skip - 1;
 			continue;
 		}
 
@@ -856,14 +855,15 @@ void flow_defer_handler(const struct ctx *c, const struct timespec *now)
 
 			if (free_head) {
 				/* Add slot to current free cluster */
-				ASSERT(idx == FLOW_IDX(free_head) + free_head->n);
+				ASSERT(FLOW_IDX(flow) ==
+				       FLOW_IDX(free_head) + free_head->n);
 				free_head->n++;
 				flow->free.n = flow->free.next = 0;
 			} else {
 				/* Create new free cluster */
 				free_head = &flow->free;
 				free_head->n = 1;
-				*last_next = idx;
+				*last_next = FLOW_IDX(flow);
 				last_next = &free_head->next;
 			}
 		} else {
diff --git a/flow_table.h b/flow_table.h
index 9a2ff24a..6ff6d0f6 100644
--- a/flow_table.h
+++ b/flow_table.h
@@ -74,6 +74,37 @@ static inline unsigned flow_idx(const struct flow_common *f)
  */
 #define FLOW(idx)		(&flowtab[(idx)])
 
+/**
+ * flow_foreach_slot() - 'for' type macro to step through every flow slot
+ * @flow_:	Points to each flow entry in order, including free slots
+ */
+#define flow_foreach_slot(flow_)					\
+	for ((flow_) = flowtab;	FLOW_IDX(flow_) < FLOW_MAX; (flow_)++)
+
+/**
+ * flow_foreach() - 'for' type macro to step through every active flow
+ * @flow_:	Points to each active flow in order
+ */
+#define flow_foreach(flow_)						\
+	flow_foreach_slot(flow_)					\
+		if ((flow_)->f.state == FLOW_STATE_FREE) {		\
+			(flow_) += (flow_)->free.n - 1;			\
+		} else if ((flow)->f.state != FLOW_STATE_ACTIVE) {	\
+			flow_err((flow_), "BUG: Traversing non-active flow"); \
+			continue;					\
+		} else
+
+/**
+ * flow_foreach_of_type() - step through active flows of one type
+ * @flow_:	Points to each active flow in order
+ * @type_:	Flow type to select
+ */
+#define flow_foreach_of_type(flow_, type_)				\
+	flow_foreach(flow_)						\
+		if ((flow_)->f.type != (type_))				\
+			continue;					\
+		else
+
 /** flow_at_sidx() - Flow entry for a given sidx
  * @sidx:	Flow & side index
  *
-- 
@@ -74,6 +74,37 @@ static inline unsigned flow_idx(const struct flow_common *f)
  */
 #define FLOW(idx)		(&flowtab[(idx)])
 
+/**
+ * flow_foreach_slot() - 'for' type macro to step through every flow slot
+ * @flow_:	Points to each flow entry in order, including free slots
+ */
+#define flow_foreach_slot(flow_)					\
+	for ((flow_) = flowtab;	FLOW_IDX(flow_) < FLOW_MAX; (flow_)++)
+
+/**
+ * flow_foreach() - 'for' type macro to step through every active flow
+ * @flow_:	Points to each active flow in order
+ */
+#define flow_foreach(flow_)						\
+	flow_foreach_slot(flow_)					\
+		if ((flow_)->f.state == FLOW_STATE_FREE) {		\
+			(flow_) += (flow_)->free.n - 1;			\
+		} else if ((flow)->f.state != FLOW_STATE_ACTIVE) {	\
+			flow_err((flow_), "BUG: Traversing non-active flow"); \
+			continue;					\
+		} else
+
+/**
+ * flow_foreach_of_type() - step through active flows of one type
+ * @flow_:	Points to each active flow in order
+ * @type_:	Flow type to select
+ */
+#define flow_foreach_of_type(flow_, type_)				\
+	flow_foreach(flow_)						\
+		if ((flow_)->f.type != (type_))				\
+			continue;					\
+		else
+
 /** flow_at_sidx() - Flow entry for a given sidx
  * @sidx:	Flow & side index
  *
-- 
2.48.1