> Quoting Michael S. Tsirkin <[EMAIL PROTECTED]>:
> Subject: Re: [ofa-general] Re: dst_ifdown breaks infiniband?
>
> > Quoting Eric W. Biederman <ebiederman@lnxi.com>:
> > Subject: Re: [ofa-general] Re: dst_ifdown breaks infiniband?
> >
> > "Michael S. Tsirkin" <[EMAIL PROTECTED]> writes:
> >
> > >> > Why is neighbour->dev changed here?
> > >>
> > >> It holds reference to device and prevents its destruction.
> > >> If dst is held somewhere, we cannot destroy the device and deadlock
> > >> while unregister.
> > >
> > > BTW, can this ever happen for the loopback device itself?
> > > Is it ever unregistered?
> >
> > Well I don't think the loopback device is currently but as soon
> > as we get network namespace support we will have multiple loopback
> > devices and they will get unregistered when we remove the network
> > namespace.
>
> Hmm. Then the code moving dst->dev to point to the loopback
> device will have to be fixed too. I'll post a patch a bit later.
Does this look sane (untested)?
Signed-off-by: Michael S. Tsirkin <[EMAIL PROTECTED]>
diff --git a/net/core/dst.c b/net/core/dst.c
index 764bccb..8283158 100644
--- a/net/core/dst.c
+++ b/net/core/dst.c
@@ -235,6 +236,8 @@ again:
static inline void dst_ifdown(struct dst_entry *dst, struct net_device *dev,
int unregister)
{
+ struct neighbour *neigh;
+
if (dst->ops->ifdown)
dst->ops->ifdown(dst, dev, unregister);
@@ -245,14 +248,13 @@ static inline void dst_ifdown(struct dst_entry *dst,
struct net_device *dev,
dst->input = dst_discard_in;
dst->output = dst_discard_out;
} else {
- dst->dev = &loopback_dev;
- dev_hold(&loopback_dev);
- dev_put(dev);
- if (dst->neighbour && dst->neighbour->dev == dev) {
- dst->neighbour->dev = &loopback_dev;
- dev_put(dev);
- dev_hold(&loopback_dev);
+ neigh = dst->neighbour;
+ if (neigh && neigh->dev == dev) {
+ dst->neighbour = NULL;
+ neigh_release(neigh);
}
+ dst->dev = NULL;
+ dev_put(dev);
}
}
--
MST
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