Bluetooth: Mesh: Invalidate pending entries before calling settings API

If, while storing app or net key, or changing cdb, we receive another
mesh message that affects setting of the same key that the mesh
currently stores, the new change won't be stored.

The settings subsystem API has rescheduling point inside. The mesh
settings are stored in the system workqueue and by default mesh messages
are processed from BT RX thread which has higher priority than the
system workqueue.

When the case above happens, a new change will be written to the same
cache entry. But this cache entry will be invalidated after leaving
settings API, which in turns will invalidate the new change:

- Receive Config AppKey Add message
cfg_srv.c -> app_keys.c: bt_mesh_app_key_add()
app_keys.c: update_app_key_settings()
app_keys.c: bt_mesh_settings_store_schedule()
- store_pending() in settings.c is scheduled
settings.c -> app_keys.c: bt_mesh_app_key_pending_store()
app_keys.c: store_app_key() called to store new app key
app_keys.c: settings_save_one() calls flash driver and sleeps
- Receive Config AppKey Delete message while in sleep,
  which wakes up BT RX thread before returning to the system workqueue
cfg_srv.c -> app_keys.c: bt_mesh_app_key_del()
app_keys.c: update_app_key_settings()
app_keys.c: app_key_update_find() finds entry and returns it
app_keys.c: update->clear = 1
app_keys.c: bt_mesh_settings_store_schedule()
- returning back to bt_mesh_app_key_pending_store() from
  settings_save_one()
app_keys.c: update->valid = 0
- the key won't be deleted next time store_pending() is scheduled.

This change moves entry invalidation before calling settings API so that
after returning from settings API, a new change won't be unintentionally
invalidated.

Signed-off-by: Pavel Vasilyev <pavel.vasilyev@nordicsemi.no>

subsys/bluetooth/mesh/app_keys.c

@@ -665,12 +665,12 @@ void bt_mesh_app_key_pending_store(void)
 			continue;
 		}
 
+		update->valid = 0U;
+
 		if (update->clear) {
 			clear_app_key(update->key_idx);
 		} else {
 			store_app_key(update->key_idx);
 		}
-
-		update->valid = 0U;
 	}
 }

subsys/bluetooth/mesh/cdb.c

@@ -1023,27 +1023,29 @@ static void store_cdb_pending_nodes(void)
 
 	for (i = 0; i < ARRAY_SIZE(cdb_node_updates); ++i) {
 		struct node_update *update = &cdb_node_updates[i];
+		uint16_t addr;
 
 		if (update->addr == BT_MESH_ADDR_UNASSIGNED) {
 			continue;
 		}
 
-		LOG_DBG("addr: 0x%04x, clear: %d", update->addr, update->clear);
+		addr = update->addr;
+		update->addr = BT_MESH_ADDR_UNASSIGNED;
+
+		LOG_DBG("addr: 0x%04x, clear: %d", addr, update->clear);
 
 		if (update->clear) {
-			clear_cdb_node(update->addr);
+			clear_cdb_node(addr);
 		} else {
 			struct bt_mesh_cdb_node *node;
 
-			node = bt_mesh_cdb_node_get(update->addr);
+			node = bt_mesh_cdb_node_get(addr);
 			if (node) {
 				store_cdb_node(node);
 			} else {
-				LOG_WRN("Node 0x%04x not found", update->addr);
+				LOG_WRN("Node 0x%04x not found", addr);
 			}
 		}
-
-		update->addr = BT_MESH_ADDR_UNASSIGNED;
 	}
 }
 
@@ -1058,6 +1060,8 @@ static void store_cdb_pending_keys(void)
 			continue;
 		}
 
+		update->valid = 0U;
+
 		if (update->clear) {
 			if (update->app_key) {
 				clear_cdb_app_key(update->key_idx);
@@ -1085,8 +1089,6 @@ static void store_cdb_pending_keys(void)
 				}
 			}
 		}
-
-		update->valid = 0U;
 	}
 }
 

subsys/bluetooth/mesh/subnet.c

@@ -831,12 +831,12 @@ void bt_mesh_subnet_pending_store(void)
 			continue;
 		}
 
+		update->valid = 0U;
+
 		if (update->clear) {
 			clear_net_key(update->key_idx);
 		} else {
 			store_subnet(update->key_idx);
 		}
-
-		update->valid = 0U;
 	}
 }