On 01/27/2014 06:30 PM, Ben Hutchings wrote: > On Mon, 2014-01-27 at 18:28 +0800, Jason Wang wrote: >> On 01/27/2014 06:22 PM, Ben Hutchings wrote: >>> On Mon, 2014-01-27 at 17:40 +0800, Jason Wang wrote: >>>> On 01/27/2014 04:35 PM, David Miller wrote: >>>>> From: Jason Wang <jasowang@xxxxxxxxxx> >>>>> Date: Mon, 27 Jan 2014 15:30:54 +0800 >>>>> >>>>>> Call netif_carrier_on() after register_device(). Otherwise it won't work since >>>>>> the device was still in NETREG_UNINITIALIZED state. >>>>>> >>>>>> Fixes a68f9614614749727286f675d15f1e09d13cb54a >>>>>> (hyperv: Fix race between probe and open calls) >>>>>> >>>>>> Cc: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx> >>>>>> Cc: K. Y. Srinivasan <kys@xxxxxxxxxxxxx> >>>>>> Reported-by: Di Nie <dnie@xxxxxxxxxx> >>>>>> Tested-by: Di Nie <dnie@xxxxxxxxxx> >>>>>> Signed-off-by: Jason Wang <jasowang@xxxxxxxxxx> >>>>> A device up can occur at the moment you call register_netdevice(), >>>>> therefore that up call can see the carrier as down and fail or >>>>> similar. So you really cannot resolve the carrier to be on in this >>>>> way. >>>> True, we need a workqueue to synchronize them. >>> Whatever for? All you need to do is: >>> >>> rtnl_lock(); >>> register_netdevice(); >>> netif_carrier_on(); >>> rtnl_unlock(); >>> >>> It would be nice if we could make the current code work with a change in >>> the core, though. >>> >>> Ben. >>> >> Looks like the link status interrupt may happen during this (after >> netvsc_device_add() was called by rndis_filter_device_add()) without any >> synchronization. This may lead a wrong link status here. > Now I'm confused - if there's a link status interrupt, why are you > setting the carrier on initially? > > Ben. > I realize that setting carrier on initially was a bug after David's comment. So I think we need a workqueue. _______________________________________________ devel mailing list devel@xxxxxxxxxxxxxxxxxxxxxx http://driverdev.linuxdriverproject.org/mailman/listinfo/driverdev-devel
