bridge: allow zero ageing time

This fixes a regression in the bridge ageing time caused by:
commit c62987bbd8a1 ("bridge: push bridge setting ageing_time down to switchdev")

There are users of Linux bridge which use the feature that if ageing time
is set to 0 it causes entries to never expire. See:
  https://www.linuxfoundation.org/collaborate/workgroups/networking/bridge

For a pure software bridge, it is unnecessary for the code to have
arbitrary restrictions on what values are allowable.

Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
Acked-by: Jiri Pirko <jiri@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/include/linux/if_bridge.h b/include/linux/if_bridge.h
index a338a68..dcb89e3 100644 (file)
--- a/include/linux/if_bridge.h
+++ b/include/linux/if_bridge.h
@@ -46,10 +46,6 @@ struct br_ip_list {
 #define BR_LEARNING_SYNC       BIT(9)
 #define BR_PROXYARP_WIFI       BIT(10)
 
-/* values as per ieee8021QBridgeFdbAgingTime */
-#define BR_MIN_AGEING_TIME     (10 * HZ)
-#define BR_MAX_AGEING_TIME     (1000000 * HZ)
-
 #define BR_DEFAULT_AGEING_TIME (300 * HZ)
 
 extern void brioctl_set(int (*ioctl_hook)(struct net *, unsigned int, void __user *));

diff --git a/net/bridge/br_stp.c b/net/bridge/br_stp.c
index c22816a..e234490 100644 (file)
--- a/net/bridge/br_stp.c
+++ b/net/bridge/br_stp.c
@@ -562,6 +562,14 @@ int br_set_max_age(struct net_bridge *br, unsigned long val)
 
 }
 
+/* Set time interval that dynamic forwarding entries live
+ * For pure software bridge, allow values outside the 802.1
+ * standard specification for special cases:
+ *  0 - entry never ages (all permanant)
+ *  1 - entry disappears (no persistance)
+ *
+ * Offloaded switch entries maybe more restrictive
+ */
 int br_set_ageing_time(struct net_bridge *br, u32 ageing_time)
 {
        struct switchdev_attr attr = {
@@ -573,9 +581,6 @@ int br_set_ageing_time(struct net_bridge *br, u32 ageing_time)
        unsigned long t = clock_t_to_jiffies(ageing_time);
        int err;
 
-       if (t < BR_MIN_AGEING_TIME || t > BR_MAX_AGEING_TIME)
-               return -ERANGE;
-
        err = switchdev_port_attr_set(br->dev, &attr);
        if (err)
                return err;