Re: [PATCH 3/5] net/mlx4_en: Call netif_carrier_off() after register_netdev()
On Tue, 2012-08-14 at 12:36 +, sathya.pe...@emulex.com wrote: > >-Original Message- > >From: netdev-ow...@vger.kernel.org [mailto:netdev-ow...@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. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
RE: [PATCH 3/5] net/mlx4_en: Call netif_carrier_off() after register_netdev()
>-Original Message- >From: netdev-ow...@vger.kernel.org [mailto:netdev-ow...@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? -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
RE: [PATCH 3/5] net/mlx4_en: Call netif_carrier_off() after register_netdev()
-Original Message- From: netdev-ow...@vger.kernel.org [mailto:netdev-ow...@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? -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
Re: [PATCH 3/5] net/mlx4_en: Call netif_carrier_off() after register_netdev()
On Tue, 2012-08-14 at 12:36 +, sathya.pe...@emulex.com wrote: -Original Message- From: netdev-ow...@vger.kernel.org [mailto:netdev-ow...@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. -- To unsubscribe from this list: send the line unsubscribe linux-kernel in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
