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

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 */

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) { + lnk->speed = 0; + ret = 0; + goto cleanup; + } +

VIR_FREE(path); VIR_FREE(buf); @@ -1884,6 +1894,7 @@ virNetDevGetLinkInfo(const char *ifname, if (virFileReadAll(path, 1024, &buf) < 0) { /* Some devices doesn't report speed, in which case we get EINVAL */ if (errno == EINVAL) { + lnk->speed = 0; ret = 0; goto cleanup; } -- 1.8.5.5