[dpdk-dev] [PATCH v2] net/failsafe: safer subdev iterator

[Gaetan Rivet]

The sub_device iterator macro should follow the general gist of the
tailq API for an easier understanding and safer use.

Once the loop has finished, the iterator should be set to NULL.
If no sub_device was iterated upon, the iterator should still be NULL.

Signed-off-by: Gaetan Rivet <gaetan.rivet at 6wind.com>
---

v2:

  - Rewrite fs_find_next to simplify the macro using it.

 drivers/net/failsafe/failsafe_private.h | 32 ++++++++++++++++++++------------
 1 file changed, 20 insertions(+), 12 deletions(-)

diff --git a/drivers/net/failsafe/failsafe_private.h b/drivers/net/failsafe/failsafe_private.h
index 0361cf4..19d36ab 100644
--- a/drivers/net/failsafe/failsafe_private.h
+++ b/drivers/net/failsafe/failsafe_private.h
@@ -220,10 +220,10 @@ extern int mac_from_arg;
  * dev:   (struct rte_eth_dev *), fail-safe ethdev
  * state: (enum dev_state), minimum acceptable device state
  */
-#define FOREACH_SUBDEV_STATE(s, i, dev, state)				\
-	for (i = fs_find_next((dev), 0, state);				\
-	     i < PRIV(dev)->subs_tail && (s = &PRIV(dev)->subs[i]);	\
-	     i = fs_find_next((dev), i + 1, state))
+#define FOREACH_SUBDEV_STATE(s, i, dev, state)		\
+	for (s = fs_find_next((dev), 0, state, &i);	\
+	     s != NULL;					\
+	     s = fs_find_next((dev), i + 1, state, &i))
 
 /**
  * Iterator construct over fail-safe sub-devices:
@@ -294,18 +294,26 @@ extern int mac_from_arg;
 
 /* inlined functions */
 
-static inline uint8_t
-fs_find_next(struct rte_eth_dev *dev, uint8_t sid,
-		enum dev_state min_state)
+static inline struct sub_device *
+fs_find_next(struct rte_eth_dev *dev,
+	     uint8_t sid,
+	     enum dev_state min_state,
+	     uint8_t *sid_out)
 {
-	while (sid < PRIV(dev)->subs_tail) {
-		if (PRIV(dev)->subs[sid].state >= min_state)
+	struct sub_device *subs;
+	uint8_t tail;
+
+	subs = PRIV(dev)->subs;
+	tail = PRIV(dev)->subs_tail;
+	while (sid < tail) {
+		if (subs[sid].state >= min_state)
 			break;
 		sid++;
 	}
-	if (sid >= PRIV(dev)->subs_tail)
-		return PRIV(dev)->subs_tail;
-	return sid;
+	*sid_out = sid;
+	if (sid >= tail)
+		return NULL;
+	return &subs[sid];
 }
 
 /*
-- 
2.1.4