Applied base-0027-Prevent abandoning the mailbox state machines early

Fixup for f943348d - caused deadlock.

Fixes the exit condition of the mailbox FSMs -- previously they returned
whether they were sending a datagram or not, and the parent assumed that
this meant they were done if they didn't want to send a datagram. Since
earlier patches can cause idle cycles now, this could cause unexpected
early exit, so they now return whether they're complete or not
explicitly.

master/fsm_coe.c

@@ -230,35 +230,34 @@ void ec_fsm_coe_transfer(
 
 /** Executes the current state of the state machine.
  *
- * \return 1 if the datagram was used, else 0.
+ * \return 1 if the state machine is still in progress, else 0.
  */
 int ec_fsm_coe_exec(
         ec_fsm_coe_t *fsm, /**< Finite state machine. */
         ec_datagram_t *datagram /**< Datagram to use. */
         )
 {
-    int datagram_used = 0;
-
+    if (fsm->state == ec_fsm_coe_end || fsm->state == ec_fsm_coe_error)
+        return 0;
     if (fsm->datagram &&
             (fsm->datagram->state == EC_DATAGRAM_INIT ||
              fsm->datagram->state == EC_DATAGRAM_QUEUED ||
              fsm->datagram->state == EC_DATAGRAM_SENT)) {
         // datagram not received yet
-        return datagram_used;
+        if (datagram != fsm->datagram)
+            datagram->state = EC_DATAGRAM_INVALID;
+        return 1;
     }
 
     fsm->state(fsm, datagram);
 
-    datagram_used =
-        fsm->state != ec_fsm_coe_end && fsm->state != ec_fsm_coe_error;
-
-    if (datagram_used) {
-        fsm->datagram = datagram;
-    } else {
+    if (fsm->state == ec_fsm_coe_end || fsm->state == ec_fsm_coe_error) {
         fsm->datagram = NULL;
+        return 0;
     }
 
-    return datagram_used;
+    fsm->datagram = datagram;
+    return 1;
 }
 
 /*****************************************************************************/

master/fsm_eoe.c

@@ -101,35 +101,35 @@ void ec_fsm_eoe_set_ip_param(
 
 /** Executes the current state of the state machine.
  *
- * \return 1 if the datagram was used, else 0.
+ * \return 1 if the state machine is still in progress, else 0.
  */
 int ec_fsm_eoe_exec(
         ec_fsm_eoe_t *fsm, /**< finite state machine */
         ec_datagram_t *datagram /**< Datagram to use. */
         )
 {
-    int datagram_used = 0;
+    if (fsm->state == ec_fsm_eoe_end || fsm->state == ec_fsm_eoe_error)
+        return 0;
 
     if (fsm->datagram &&
             (fsm->datagram->state == EC_DATAGRAM_INIT ||
              fsm->datagram->state == EC_DATAGRAM_QUEUED ||
              fsm->datagram->state == EC_DATAGRAM_SENT)) {
         // datagram not received yet
-        return datagram_used;
+        if (datagram != fsm->datagram)
+            datagram->state = EC_DATAGRAM_INVALID;
+        return 1;
     }
 
     fsm->state(fsm, datagram);
 
-    datagram_used =
-        fsm->state != ec_fsm_eoe_end && fsm->state != ec_fsm_eoe_error;
-
-    if (datagram_used) {
-        fsm->datagram = datagram;
-    } else {
+    if (fsm->state == ec_fsm_eoe_end || fsm->state == ec_fsm_eoe_error) {
         fsm->datagram = NULL;
+        return 0;
     }
 
-    return datagram_used;
+    fsm->datagram = datagram;
+    return 1;
 }
 
 /*****************************************************************************/

master/fsm_foe.c

@@ -123,35 +123,35 @@ void ec_fsm_foe_clear(ec_fsm_foe_t *fsm /**< finite state machine */)
 
 /** Executes the current state of the state machine.
  *
- * \return 1, if the datagram was used, else 0.
+ * \return 1 if the state machine is still in progress, else 0.
  */
 int ec_fsm_foe_exec(
         ec_fsm_foe_t *fsm, /**< finite state machine */
         ec_datagram_t *datagram /**< Datagram to use. */
         )
 {
-    int datagram_used = 0;
+    if (fsm->state == ec_fsm_foe_end || fsm->state == ec_fsm_foe_error)
+        return 0;
 
     if (fsm->datagram &&
             (fsm->datagram->state == EC_DATAGRAM_INIT ||
              fsm->datagram->state == EC_DATAGRAM_QUEUED ||
              fsm->datagram->state == EC_DATAGRAM_SENT)) {
         // datagram not received yet
-        return datagram_used;
+        if (datagram != fsm->datagram)
+            datagram->state = EC_DATAGRAM_INVALID;
+        return 1;
     }
 
     fsm->state(fsm, datagram);
 
-    datagram_used =
-        fsm->state != ec_fsm_foe_end && fsm->state != ec_fsm_foe_error;
-
-    if (datagram_used) {
-        fsm->datagram = datagram;
-    } else {
+    if (fsm->state == ec_fsm_foe_end || fsm->state == ec_fsm_foe_error) {
         fsm->datagram = NULL;
+        return 0;
     }
 
-    return datagram_used;
+    fsm->datagram = datagram;
+    return 1;
 }
 
 /*****************************************************************************/

master/fsm_soe.c

@@ -147,35 +147,35 @@ void ec_fsm_soe_transfer(
 
 /** Executes the current state of the state machine.
  *
- * \return 1 if the datagram was used, else 0.
+ * \return 1 if the state machine is still in progress, else 0.
  */
 int ec_fsm_soe_exec(
         ec_fsm_soe_t *fsm, /**< finite state machine */
         ec_datagram_t *datagram /**< Datagram to use. */
         )
 {
-    int datagram_used = 0;
+    if (fsm->state == ec_fsm_soe_end || fsm->state == ec_fsm_soe_error)
+        return 0;
 
     if (fsm->datagram &&
             (fsm->datagram->state == EC_DATAGRAM_INIT ||
              fsm->datagram->state == EC_DATAGRAM_QUEUED ||
              fsm->datagram->state == EC_DATAGRAM_SENT)) {
         // datagram not received yet
-        return datagram_used;
+        if (datagram != fsm->datagram)
+            datagram->state = EC_DATAGRAM_INVALID;
+        return 1;
     }
 
     fsm->state(fsm, datagram);
 
-    datagram_used =
-        fsm->state != ec_fsm_soe_end && fsm->state != ec_fsm_soe_error;
-
-    if (datagram_used) {
-        fsm->datagram = datagram;
-    } else {
+    if (fsm->state == ec_fsm_soe_end || fsm->state == ec_fsm_soe_error) {
         fsm->datagram = NULL;
+        return 0;
     }
 
-    return datagram_used;
+    fsm->datagram = datagram;
+    return 1;
 }
 
 /*****************************************************************************/