lkml.org 
[lkml]   [2020]   [Sep]   [24]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
/
SubjectRe: [PATCH] Revert "net: linkwatch: add check for netdevice being present to linkwatch_do_dev"
From
Date
On Thu, 2020-09-24 at 09:03 -0700, Jakub Kicinski wrote:
> On Wed, 23 Sep 2020 22:49:37 -0700 Saeed Mahameed wrote:
> > 2) Another problematic scenario which i see is repeated in many
> > drivers:
> >
> > shutdown/suspend()
> > rtnl_lock()
> > netif_device_detach()//Mark !present;
> > stop()->carrier_off()->linkwatch_event()
> > // at this point device is still IFF_UP and !present
> > // due to the early detach above..
> > rtnl_unlock();
>
> Maybe we can solve this by providing drivers with a better helper for
> the suspend use case?
>
> AFAIU netif_device_detach() is used by both IO errors and drivers
> willingly detaching the device during normal operation (e.g. for
> suspend).
>
> Since the suspend path can sleep if we have a separate helper perhaps
> we could fire off the appropriate events synchronously, and
> quiescence
> the stack properly?

I was thinking something similar, a more heavy
weight netif_device_detach(), which will be used in all drivers suspend
flows.

1) clear IFF_UP
2) ndo_stop()
3) fire events
4) mark !present
...

5) suspend device


but went and sampled some drivers and found there are many variations
for using netif_device_detach it is not going to be a simple task.

\
 
 \ /
  Last update: 2020-09-24 20:17    [W:0.105 / U:3.024 seconds]
©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site