Fri, Jun 06, 2014 at 10:40:30AM CEST, mpriv...@redhat.com wrote:
>The link speed is available at /sys/class/net/$nic/speed.
>However, in some cases, depending on the driver, if the link is
>not plugged, -1 is reported (this is the case of e1000e for
>instance). To make things worse, the value is printed out as an
Actually, SPEED_UNKNOWN is also -1
So e1000e is not any exception.
>unsigned integer, so you'll get this shady number which you can't
>evaluate correctly. This is actually a regression in 3.X kernels
>as the commit that broke things is 8ae6daca. With this change,
>you'll get -EINVAL whenever a -1 is to be printed out.
>
>Before the change:
> # cat /sys/class/net/eth0/speed
> 4294967295
>
>After the change:
> # cat /sys/class/net/eth0/speed
> cat: /sys/class/net/eth0/speed: Invalid argument
>
>Signed-off-by: Michal Privoznik <mpriv...@redhat.com>
>---
> net/core/net-sysfs.c | 9 +++++++--
> 1 file changed, 7 insertions(+), 2 deletions(-)
>
>diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
>index 1cac29e..ce4b298 100644
>--- a/net/core/net-sysfs.c
>+++ b/net/core/net-sysfs.c
>@@ -172,8 +172,13 @@ static ssize_t speed_show(struct device *dev,
>
> if (netif_running(netdev)) {
> struct ethtool_cmd cmd;
>- if (!__ethtool_get_settings(netdev, &cmd))
>- ret = sprintf(buf, fmt_udec, ethtool_cmd_speed(&cmd));
>+ if (!__ethtool_get_settings(netdev, &cmd)) {
>+ __u32 speed = ethtool_cmd_speed(&cmd);
>+
>+ if (speed != (__u32) -1)
Just rather use SPEED_UNKNOWN instead of -1 here.
>+ ret = sprintf(buf, fmt_udec,
>+ ethtool_cmd_speed(&cmd));
>+ }
> }
> rtnl_unlock();
> return ret;
>--
>2.0.0
>
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