Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752580AbaFFI5j (ORCPT ); Fri, 6 Jun 2014 04:57:39 -0400 Received: from mail-we0-f169.google.com ([74.125.82.169]:42179 "EHLO mail-we0-f169.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751871AbaFFI5g (ORCPT ); Fri, 6 Jun 2014 04:57:36 -0400 Date: Fri, 6 Jun 2014 10:57:33 +0200 From: Jiri Pirko To: Michal Privoznik Cc: davem@davemloft.net, gregkh@linuxfoundation.org, linux-kernel@vger.kernel.org, netdev@vger.kernel.org Subject: Re: [PATCH] net-sysfs: Report link speed only when possible Message-ID: <20140606085733.GJ2984@minipsycho.orion> References: <771f792d4d4391c656305a522557c53c4e84a666.1402043894.git.mprivozn@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <771f792d4d4391c656305a522557c53c4e84a666.1402043894.git.mprivozn@redhat.com> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Fri, Jun 06, 2014 at 10:40:30AM CEST, mprivozn@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 >--- > 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 > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/