Messages in this thread | | | From | Florian Fainelli <> | Date | Mon, 2 Jun 2014 10:21:43 -0700 | Subject | Re: [PATCH] net-sysfs: Report link speed as signed integer |
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2014-06-02 8:01 GMT-07:00 Veaceslav Falico <vfalico@redhat.com>: > On Mon, Jun 02, 2014 at 04:35:57PM +0200, Jiri Pirko wrote: >> >> Mon, Jun 02, 2014 at 04:25:15PM CEST, mprivozn@redhat.com wrote: >>> >>> The link speed is available at /sys/class/net/$nic/speed. >>> However, the speed is printed in unsigned integer format. This >>> makes userspace applications read an incorrect value (which >>> moreover changes through several architectures) while in fact >>> '-1' should be reported. >>> >>> Before the change: >>> # cat /sys/class/net/eth0/speed >>> 4294967295 >>> >>> After the change: >>> # cat /sys/class/net/eth0/speed >>> -1 >>> >>> Signed-off-by: Michal Privoznik <mprivozn@redhat.com> >>> --- >>> net/core/net-sysfs.c | 2 +- >>> 1 file changed, 1 insertion(+), 1 deletion(-) >>> >>> diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c >>> index 1cac29e..99afdea 100644 >>> --- a/net/core/net-sysfs.c >>> +++ b/net/core/net-sysfs.c >>> @@ -173,7 +173,7 @@ 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)); >>> + ret = sprintf(buf, fmt_dec, >>> ethtool_cmd_speed(&cmd)); >> >> >> I wonder why this should be signed. What -1 means? What driver reports >> this? > > > My first thoughts were exactly this. There is SPEED_UNKOWN (along with > _10, _100, _1000 etc.) that's -1, and quite a few drivers use it/set it. > > I wonder, though, if we should document it or just output "Unknown" instead > of -1.
I would document the special "Unkown" value in Documentation/ABI/testing/sysfs-class-net and update speed_show() to handle it. -1 is confusing for anyone to realize what this means.
> >> >>> } >>> rtnl_unlock(); >>> return ret; >>> -- >>> 2.0.0 >>> >> -- >> To unsubscribe from this list: send the line "unsubscribe netdev" in >> >> the body of a message to majordomo@vger.kernel.org >> More majordomo info at http://vger.kernel.org/majordomo-info.html > > -- > To unsubscribe from this list: send the line "unsubscribe netdev" in > > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html
-- Florian
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