When debugging faulty hardware (in case of virt, faulty
emulation) I found it helpful to be able to examine
stopped status of the interface. The following patch makes
this visible in sysfs.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
 net/core/net-sysfs.c |   11 +++++++++++
 1 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/net/core/net-sysfs.c b/net/core/net-sysfs.c
index c57c4b2..e1f80c0 100644
--- a/net/core/net-sysfs.c
+++ b/net/core/net-sysfs.c
@@ -132,6 +132,16 @@ static ssize_t show_carrier(struct device *dev,
 	return -EINVAL;
 }
 
+static ssize_t show_stopped(struct device *dev,
+			    struct device_attribute *attr, char *buf)
+{
+	struct net_device *netdev = to_net_dev(dev);
+	if (netif_running(netdev)) {
+		return sprintf(buf, fmt_dec, !!netif_queue_stopped(netdev));
+	}
+	return -EINVAL;
+}
+
 static ssize_t show_speed(struct device *dev,
 			  struct device_attribute *attr, char *buf)
 {
@@ -303,6 +313,7 @@ static struct device_attribute net_class_attributes[] = {
 	__ATTR(address, S_IRUGO, show_address, NULL),
 	__ATTR(broadcast, S_IRUGO, show_broadcast, NULL),
 	__ATTR(carrier, S_IRUGO, show_carrier, NULL),
+	__ATTR(carrier, S_IRUGO, show_stopped, NULL),
 	__ATTR(speed, S_IRUGO, show_speed, NULL),
 	__ATTR(duplex, S_IRUGO, show_duplex, NULL),
 	__ATTR(dormant, S_IRUGO, show_dormant, NULL),
-- 
1.7.1.rc1.22.g3163
--

[ message continues ]

[...]

This is a per-queue attribute and should not be associated directly with
the netdev.

Ben.

-- 
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.
They asked us to note that Solarflare product names are trademarked.

--

[ message continues ]

From: Ben Hutchings <bhutchings@solarflare.com>

Right.
--

[ message continues ]

From: "Michael S. Tsirkin" <mst@redhat.com>

Besides the fact that you have to publish this as a per-queue attribute,
you're also erroneously naming it 'carrier' here.
--

[ message continues ]