Re: [libvirt] [PATCH] virNetDevGetLinkInfo: Don't report link speed if NIC's down

On Fri, Jun 13, 2014 at 08:46:59AM +0200, Michal Privoznik wrote: > The kernel's more broken than one would think. Various drivers report > various (usually spurious) values if the interface is down. While on > some we experience -EINVAL when read()-ing the speed sysfs file, with > other drivers we might get anything from 0 to UINT_MAX. If that's the > case it's better to not report link speed. Well, the interface is down > anyway. > > Signed-off-by: Michal Privoznik <mprivozn(a)redhat.com&gt; > --- > src/util/virnetdev.c | 13 ++++++++++++- > 1 file changed, 12 insertions(+), 1 deletion(-) > > diff --git a/src/util/virnetdev.c b/src/util/virnetdev.c > index 6f3a202..80ef572 100644 > --- a/src/util/virnetdev.c > +++ b/src/util/virnetdev.c > @@ -1843,7 +1843,7 @@ virNetDevGetLinkInfo(const char *ifname, > char *buf = NULL; > char *tmp; > int tmp_state; > - unsigned int tmp_speed; > + unsigned int tmp_speed; /* virInterfaceState */ > You probably wanted to put this comment next to the line with tmp_state and not tmp_speed. > if (virNetDevSysfsFile(&path, ifname, "operstate") < 0) > goto cleanup; > @@ -1875,6 +1875,16 @@ virNetDevGetLinkInfo(const char *ifname, > > lnk->state = tmp_state; > > + /* Shortcut to avoid some kernel issues. If link is down (and > possibly in > + * other states too) several drivers report several values. > While igb > + * reports 65535, realtek goes with 10. To avoid muddying XML > with insane > + * values, don't report link speed */ > + if (lnk->state == VIR_INTERFACE_STATE_DOWN) {