Messages in this thread | | | Subject | Re: [PATCH 3/5] net/mlx4_en: Call netif_carrier_off() after register_netdev() | From | Ben Hutchings <> | Date | Tue, 14 Aug 2012 15:56:35 +0100 |
| |
On Tue, 2012-08-14 at 12:36 +0000, Sathya.Perla@Emulex.Com wrote: > >-----Original Message----- > >From: netdev-owner@vger.kernel.org [mailto:netdev-owner@vger.kernel.org] On > >Behalf Of Ilya Shchepetkov > > > >For carrier detection to work properly when binding the driver with a > >cable unplugged, netif_carrier_off() should be called after > >register_netdev(), not before. > > > >Calling netif_carrier_off() before register_netdev() was causing the > >network interface to miss a linkwatch pending event leading to an > >inconsistent state if the link is not up when interface is initialized. > > ndo_open() may be called as soon register_netdev() completes... > When netif_carrier_off() is called *after* register_netdev(), isn't there > a possibility of a ndo_open()->netif_carrier_on() call racing this call, causing > incorrect results?
Yes, you should use something like:
rtnl_lock(); rc = register_netdevice(dev); if (rc) goto out_unlock; netif_carrier_off(dev); rtnl_unlock();
(Why do we even have register_netdev() when it's such an invitation to races?)
Ben.
-- Ben Hutchings, Staff Engineer, Solarflare Not speaking for my employer; that's the marketing department's job. They asked us to note that Solarflare product names are trademarked.
| |