bonding: add packets_per_slave attribute netlink support

Add IFLA_BOND_PACKETS_PER_SLAVE to allow get/set of bonding parameter
packets_per_slave via netlink.

Signed-off-by: Scott Feldman <sfeldma@cumulusnetworks.com>
Signed-off-by: Jiri Pirko <jiri@resnulli.us>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/bonding/bond_sysfs.c b/drivers/net/bonding/bond_sysfs.c
index c4cdbf6..a0a3476f 100644
--- a/drivers/net/bonding/bond_sysfs.c
+++ b/drivers/net/bonding/bond_sysfs.c
@@ -1409,28 +1409,22 @@
 					       const char *buf, size_t count)
 {
 	struct bonding *bond = to_bond(d);
-	int new_value, ret = count;
+	int new_value, ret;
 
 	if (sscanf(buf, "%d", &new_value) != 1) {
 		pr_err("%s: no packets_per_slave value specified.\n",
 		       bond->dev->name);
-		ret = -EINVAL;
-		goto out;
+		return -EINVAL;
 	}
-	if (new_value < 0 || new_value > USHRT_MAX) {
-		pr_err("%s: packets_per_slave must be between 0 and %u\n",
-		       bond->dev->name, USHRT_MAX);
-		ret = -EINVAL;
-		goto out;
-	}
-	if (bond->params.mode != BOND_MODE_ROUNDROBIN)
-		pr_warn("%s: Warning: packets_per_slave has effect only in balance-rr mode\n",
-			bond->dev->name);
-	if (new_value > 1)
-		bond->params.packets_per_slave = reciprocal_value(new_value);
-	else
-		bond->params.packets_per_slave = new_value;
-out:
+
+	if (!rtnl_trylock())
+		return restart_syscall();
+
+	ret = bond_option_packets_per_slave_set(bond, new_value);
+	if (!ret)
+		ret = count;
+
+	rtnl_unlock();
 	return ret;
 }