2018-05-08 17:42:15

by Mohammed Gamal

Subject: [PATCH] hv_netvsc: Fix net device attach on older Windows hosts

On older windows hosts the net_device instance is returned to
the caller of rndis_filter_device_add() without having the presence
bit set first. This would cause any subsequent calls to network device
operations (e.g. MTU change, channel change) to fail after the device
is detached once, returning -ENODEV.

Make sure we explicitly call netif_device_attach() before returning
the net_device instance to make sure the presence bit is set

Fixes: 7b2ee50c0cd5 ("hv_netvsc: common detach logic")

Signed-off-by: Mohammed Gamal <[email protected]>
---
drivers/net/hyperv/rndis_filter.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c
index 6b127be..09a3c1d 100644
--- a/drivers/net/hyperv/rndis_filter.c
+++ b/drivers/net/hyperv/rndis_filter.c
@@ -1287,8 +1287,10 @@ struct netvsc_device *rndis_filter_device_add(struct hv_device *dev,
rndis_device->hw_mac_adr,
rndis_device->link_state ? "down" : "up");

- if (net_device->nvsp_version < NVSP_PROTOCOL_VERSION_5)
+ if (net_device->nvsp_version < NVSP_PROTOCOL_VERSION_5) {
+ netif_device_attach(net);
return net_device;
+ }

rndis_filter_query_link_speed(rndis_device, net_device);

--
1.8.3.1

2018-05-08 18:14:34

by Stephen Hemminger

Subject: Re: [PATCH] hv_netvsc: Fix net device attach on older Windows hosts

On Tue, 8 May 2018 19:40:47 +0200
Mohammed Gamal <[email protected]> wrote:

> On older windows hosts the net_device instance is returned to
> the caller of rndis_filter_device_add() without having the presence
> bit set first. This would cause any subsequent calls to network device
> operations (e.g. MTU change, channel change) to fail after the device
> is detached once, returning -ENODEV.
>
> Make sure we explicitly call netif_device_attach() before returning
> the net_device instance to make sure the presence bit is set
>
> Fixes: 7b2ee50c0cd5 ("hv_netvsc: common detach logic")
>
> Signed-off-by: Mohammed Gamal <[email protected]>
> ---
> drivers/net/hyperv/rndis_filter.c | 4 +++-
> 1 file changed, 3 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c
> index 6b127be..09a3c1d 100644
> --- a/drivers/net/hyperv/rndis_filter.c
> +++ b/drivers/net/hyperv/rndis_filter.c
> @@ -1287,8 +1287,10 @@ struct netvsc_device *rndis_filter_device_add(struct hv_device *dev,
> rndis_device->hw_mac_adr,
> rndis_device->link_state ? "down" : "up");
>
> - if (net_device->nvsp_version < NVSP_PROTOCOL_VERSION_5)
> + if (net_device->nvsp_version < NVSP_PROTOCOL_VERSION_5) {
> + netif_device_attach(net);
> return net_device;
> + }

Yes, this looks right, but it might be easier to use goto existing exit
path.

diff --git a/drivers/net/hyperv/rndis_filter.c b/drivers/net/hyperv/rndis_filter.c
index 3b6dbacaf77d..ed941c5a0be9 100644
--- a/drivers/net/hyperv/rndis_filter.c
+++ b/drivers/net/hyperv/rndis_filter.c
@@ -1316,7 +1316,7 @@ struct netvsc_device *rndis_filter_device_add(struct hv_device *dev,
rndis_device->link_state ? "down" : "up");

if (net_device->nvsp_version < NVSP_PROTOCOL_VERSION_5)
- return net_device;
+ goto out;

rndis_filter_query_link_speed(rndis_device, net_device);

2018-05-08 18:20:03

by Mohammed Gamal

Subject: Re: [PATCH] hv_netvsc: Fix net device attach on older Windows hosts

On Tue, 2018-05-08 at 11:13 -0700, Stephen Hemminger wrote:
> On Tue,  8 May 2018 19:40:47 +0200
> Mohammed Gamal <[email protected]> wrote:
>
> > On older windows hosts the net_device instance is returned to
> > the caller of rndis_filter_device_add() without having the presence
> > bit set first. This would cause any subsequent calls to network
> > device
> > operations (e.g. MTU change, channel change) to fail after the
> > device
> > is detached once, returning -ENODEV.
> >
> > Make sure we explicitly call netif_device_attach() before returning
> > the net_device instance to make sure the presence bit is set
> >
> > Fixes: 7b2ee50c0cd5 ("hv_netvsc: common detach logic")
> >
> > Signed-off-by: Mohammed Gamal <[email protected]>
> > ---
> >  drivers/net/hyperv/rndis_filter.c | 4 +++-
> >  1 file changed, 3 insertions(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/hyperv/rndis_filter.c
> > b/drivers/net/hyperv/rndis_filter.c
> > index 6b127be..09a3c1d 100644
> > --- a/drivers/net/hyperv/rndis_filter.c
> > +++ b/drivers/net/hyperv/rndis_filter.c
> > @@ -1287,8 +1287,10 @@ struct netvsc_device
> > *rndis_filter_device_add(struct hv_device *dev,
> >      rndis_device->hw_mac_adr,
> >      rndis_device->link_state ? "down" : "up");
> >  
> > - if (net_device->nvsp_version < NVSP_PROTOCOL_VERSION_5)
> > + if (net_device->nvsp_version < NVSP_PROTOCOL_VERSION_5) {
> > + netif_device_attach(net);
> >   return net_device;
> > + }
>
> Yes, this looks right, but it might be easier to use goto existing
> exit
> path.
>

I was just not sure if we should set max_chn and num_chn here. I will
modify the patch and resend.

> diff --git a/drivers/net/hyperv/rndis_filter.c
> b/drivers/net/hyperv/rndis_filter.c
> index 3b6dbacaf77d..ed941c5a0be9 100644
> --- a/drivers/net/hyperv/rndis_filter.c
> +++ b/drivers/net/hyperv/rndis_filter.c
> @@ -1316,7 +1316,7 @@ struct netvsc_device
> *rndis_filter_device_add(struct hv_device *dev,
>                    rndis_device->link_state ? "down" : "up");
>  
>         if (net_device->nvsp_version < NVSP_PROTOCOL_VERSION_5)
> -               return net_device;
> +               goto out;
>  
>         rndis_filter_query_link_speed(rndis_device, net_device);
>

2018-05-08 22:52:21

by Stephen Hemminger

Subject: Re: [PATCH] hv_netvsc: Fix net device attach on older Windows hosts

On Tue, 08 May 2018 20:17:51 +0200
Mohammed Gamal <[email protected]> wrote:

> On Tue, 2018-05-08 at 11:13 -0700, Stephen Hemminger wrote:
> > On Tue,  8 May 2018 19:40:47 +0200
> > Mohammed Gamal <[email protected]> wrote:
> >
> > > On older windows hosts the net_device instance is returned to
> > > the caller of rndis_filter_device_add() without having the presence
> > > bit set first. This would cause any subsequent calls to network
> > > device
> > > operations (e.g. MTU change, channel change) to fail after the
> > > device
> > > is detached once, returning -ENODEV.
> > >
> > > Make sure we explicitly call netif_device_attach() before returning
> > > the net_device instance to make sure the presence bit is set
> > >
> > > Fixes: 7b2ee50c0cd5 ("hv_netvsc: common detach logic")
> > >
> > > Signed-off-by: Mohammed Gamal <[email protected]>
> > > ---
> > >  drivers/net/hyperv/rndis_filter.c | 4 +++-
> > >  1 file changed, 3 insertions(+), 1 deletion(-)
> > >
> > > diff --git a/drivers/net/hyperv/rndis_filter.c
> > > b/drivers/net/hyperv/rndis_filter.c
> > > index 6b127be..09a3c1d 100644
> > > --- a/drivers/net/hyperv/rndis_filter.c
> > > +++ b/drivers/net/hyperv/rndis_filter.c
> > > @@ -1287,8 +1287,10 @@ struct netvsc_device
> > > *rndis_filter_device_add(struct hv_device *dev,
> > >      rndis_device->hw_mac_adr,
> > >      rndis_device->link_state ? "down" : "up");
> > >  
> > > - if (net_device->nvsp_version < NVSP_PROTOCOL_VERSION_5)
> > > + if (net_device->nvsp_version < NVSP_PROTOCOL_VERSION_5) {
> > > + netif_device_attach(net);
> > >   return net_device;
> > > + }
> >
> > Yes, this looks right, but it might be easier to use goto existing
> > exit
> > path.
> >
>
> I was just not sure if we should set max_chn and num_chn here. I will
> modify the patch and resend.


On older code it was just a goto. At that point: num_chn = max_chn = 1