[net-next-2.6 RFC PATCH] ethtool: allow custom interval for physical identification

[Bruce Allan <bruce.w.allan@intel.com>]

When physical identification of an adapter is done by toggling the
mechanism on and off through software utilizing the .set_phys_id operation,
it is done with a fixed duration for both on and off states.  Some drivers
may want to set a custom duration for the on/off intervals.  This patch
changes the API so the return code from the driver's entry point can
specify the interval duration as a positive number; -EINVAL is still
allowed in order to use the default single on/off interval per second.

Signed-off-by: Bruce Allan <bruce.w.allan@intel.com>
---

 net/core/ethtool.c |   11 +++++++----
 1 files changed, 7 insertions(+), 4 deletions(-)

diff --git a/net/core/ethtool.c b/net/core/ethtool.c
index 43ef09f..02db945 100644
--- a/net/core/ethtool.c
+++ b/net/core/ethtool.c
@@ -1640,7 +1640,7 @@ static int ethtool_phys_id(struct net_device *dev, void __user *useraddr)
 		return dev->ethtool_ops->phys_id(dev, id.data);
 
 	rc = dev->ethtool_ops->set_phys_id(dev, ETHTOOL_ID_ACTIVE);
-	if (rc && rc != -EINVAL)
+	if (rc < 0 && rc != -EINVAL)
 		return rc;
 
 	/* Drop the RTNL lock while waiting, but prevent reentry or
@@ -1656,22 +1656,25 @@ static int ethtool_phys_id(struct net_device *dev, void __user *useraddr)
 			id.data ? (id.data * HZ) : MAX_SCHEDULE_TIMEOUT);
 	} else {
 		/* Driver expects to be called periodically */
+		int i = 0, interval = ((rc > 0) ? rc : (HZ / 2));
+
 		do {
 			rtnl_lock();
 			rc = dev->ethtool_ops->set_phys_id(dev, ETHTOOL_ID_ON);
 			rtnl_unlock();
 			if (rc)
 				break;
-			schedule_timeout_interruptible(HZ / 2);
+			schedule_timeout_interruptible(interval);
 
 			rtnl_lock();
 			rc = dev->ethtool_ops->set_phys_id(dev, ETHTOOL_ID_OFF);
 			rtnl_unlock();
 			if (rc)
 				break;
-			schedule_timeout_interruptible(HZ / 2);
+			schedule_timeout_interruptible(interval);
 		} while (!signal_pending(current) &&
-			 (id.data == 0 || --id.data != 0));
+			 (id.data == 0 ||
+			  (++i * 2 * interval) < (id.data * HZ)));
 	}
 
 	rtnl_lock();