batman-adv: iv_ogm, Reduce code duplication

The difference between tq1 and tq2 are calculated the same way in two
separate functions.

This patch moves the common code to a separate function
'batadv_iv_ogm_neigh_diff' which handles everything necessary. The other
two functions can then handle errors and use the difference directly.

Signed-off-by: Markus Pargmann <mpa@pengutronix.de>
[sven@narfation.org: rebased on current version, initialize return variable
in batadv_iv_ogm_neigh_diff, add kerneldoc, convert to bool return type]
Signed-off-by: Sven Eckelmann <sven@narfation.org>
Signed-off-by: Marek Lindner <mareklindner@neomailbox.ch>
Signed-off-by: Simon Wunderlich <sw@simonwunderlich.de>

diff --git a/net/batman-adv/bat_iv_ogm.c b/net/batman-adv/bat_iv_ogm.c
index d04874fc034def63e443788e15208482b332bb57..57e0af9b39e41d2e7f81be0eedb3a72d49989353 100644 (file)
--- a/net/batman-adv/bat_iv_ogm.c
+++ b/net/batman-adv/bat_iv_ogm.c
@@ -2019,35 +2019,40 @@ static void batadv_iv_neigh_print(struct batadv_priv *bat_priv,
 }
 
 /**
- * batadv_iv_ogm_neigh_cmp - compare the metrics of two neighbors
+ * batadv_iv_ogm_neigh_diff - calculate tq difference of two neighbors
  * @neigh1: the first neighbor object of the comparison
  * @if_outgoing1: outgoing interface for the first neighbor
  * @neigh2: the second neighbor object of the comparison
  * @if_outgoing2: outgoing interface for the second neighbor
+ * @diff: pointer to integer receiving the calculated difference
  *
- * Return: a value less, equal to or greater than 0 if the metric via neigh1 is
- * lower, the same as or higher than the metric via neigh2
+ * The content of *@diff is only valid when this function returns true.
+ * It is less, equal to or greater than 0 if the metric via neigh1 is lower,
+ * the same as or higher than the metric via neigh2
+ *
+ * Return: true when the difference could be calculated, false otherwise
  */
-static int batadv_iv_ogm_neigh_cmp(struct batadv_neigh_node *neigh1,
-                                  struct batadv_hard_iface *if_outgoing1,
-                                  struct batadv_neigh_node *neigh2,
-                                  struct batadv_hard_iface *if_outgoing2)
+static bool batadv_iv_ogm_neigh_diff(struct batadv_neigh_node *neigh1,
+                                    struct batadv_hard_iface *if_outgoing1,
+                                    struct batadv_neigh_node *neigh2,
+                                    struct batadv_hard_iface *if_outgoing2,
+                                    int *diff)
 {
        struct batadv_neigh_ifinfo *neigh1_ifinfo, *neigh2_ifinfo;
        u8 tq1, tq2;
-       int diff;
+       bool ret = true;
 
        neigh1_ifinfo = batadv_neigh_ifinfo_get(neigh1, if_outgoing1);
        neigh2_ifinfo = batadv_neigh_ifinfo_get(neigh2, if_outgoing2);
 
        if (!neigh1_ifinfo || !neigh2_ifinfo) {
-               diff = 0;
+               ret = false;
                goto out;
        }
 
        tq1 = neigh1_ifinfo->bat_iv.tq_avg;
        tq2 = neigh2_ifinfo->bat_iv.tq_avg;
-       diff = tq1 - tq2;
+       *diff = (int)tq1 - (int)tq2;
 
 out:
        if (neigh1_ifinfo)
@@ -2055,6 +2060,32 @@ out:
        if (neigh2_ifinfo)
                batadv_neigh_ifinfo_put(neigh2_ifinfo);
 
+       return ret;
+}
+
+/**
+ * batadv_iv_ogm_neigh_cmp - compare the metrics of two neighbors
+ * @neigh1: the first neighbor object of the comparison
+ * @if_outgoing1: outgoing interface for the first neighbor
+ * @neigh2: the second neighbor object of the comparison
+ * @if_outgoing2: outgoing interface for the second neighbor
+ *
+ * Return: a value less, equal to or greater than 0 if the metric via neigh1 is
+ * lower, the same as or higher than the metric via neigh2
+ */
+static int batadv_iv_ogm_neigh_cmp(struct batadv_neigh_node *neigh1,
+                                  struct batadv_hard_iface *if_outgoing1,
+                                  struct batadv_neigh_node *neigh2,
+                                  struct batadv_hard_iface *if_outgoing2)
+{
+       bool ret;
+       int diff;
+
+       ret = batadv_iv_ogm_neigh_diff(neigh1, if_outgoing1, neigh2,
+                                      if_outgoing2, &diff);
+       if (!ret)
+               return 0;
+
        return diff;
 }
 
@@ -2075,29 +2106,15 @@ batadv_iv_ogm_neigh_is_sob(struct batadv_neigh_node *neigh1,
                           struct batadv_neigh_node *neigh2,
                           struct batadv_hard_iface *if_outgoing2)
 {
-       struct batadv_neigh_ifinfo *neigh1_ifinfo, *neigh2_ifinfo;
-       u8 tq1, tq2;
        bool ret;
+       int diff;
 
-       neigh1_ifinfo = batadv_neigh_ifinfo_get(neigh1, if_outgoing1);
-       neigh2_ifinfo = batadv_neigh_ifinfo_get(neigh2, if_outgoing2);
-
-       /* we can't say that the metric is better */
-       if (!neigh1_ifinfo || !neigh2_ifinfo) {
-               ret = false;
-               goto out;
-       }
-
-       tq1 = neigh1_ifinfo->bat_iv.tq_avg;
-       tq2 = neigh2_ifinfo->bat_iv.tq_avg;
-       ret = (tq1 - tq2) > -BATADV_TQ_SIMILARITY_THRESHOLD;
-
-out:
-       if (neigh1_ifinfo)
-               batadv_neigh_ifinfo_put(neigh1_ifinfo);
-       if (neigh2_ifinfo)
-               batadv_neigh_ifinfo_put(neigh2_ifinfo);
+       ret = batadv_iv_ogm_neigh_diff(neigh1, if_outgoing1, neigh2,
+                                      if_outgoing2, &diff);
+       if (!ret)
+               return false;
 
+       ret = diff > -BATADV_TQ_SIMILARITY_THRESHOLD;
        return ret;
 }