[PATCH] atm: expose ATM device index in sysfs

[Dan Williams <dcbw@redhat.com>]

It's current exposed only through /proc which besides requiring
screen-scraping doesn't allow userspace to distinguish between two
identical ATM adapters with different ATM indexes.  The ATM device index
is required when using PPPoATM on a system with multiple ATM adapters.

Signed-off-by: Dan Williams <dcbw@redhat.com>
---

PS: -> stable too since it's a minimal change with no backwards
incompatibility and I'd like to rely on this attribute in NetworkManager

diff --git a/net/atm/atm_sysfs.c b/net/atm/atm_sysfs.c
index f7fa67c..e5edbde 100644
--- a/net/atm/atm_sysfs.c
+++ b/net/atm/atm_sysfs.c
@@ -59,6 +59,16 @@ static ssize_t show_atmaddress(struct device *cdev,
 	return pos - buf;
 }
 
+static ssize_t show_atmindex(struct device *cdev,
+			     struct device_attribute *attr, char *buf)
+{
+	char *pos = buf;
+	struct atm_dev *adev = to_atm_dev(cdev);
+
+	pos += sprintf(pos, "%d\n", adev->number);
+	return pos - buf;
+}
+
 static ssize_t show_carrier(struct device *cdev,
 			    struct device_attribute *attr, char *buf)
 {
@@ -99,6 +109,7 @@ static ssize_t show_link_rate(struct device *cdev,
 
 static DEVICE_ATTR(address, S_IRUGO, show_address, NULL);
 static DEVICE_ATTR(atmaddress, S_IRUGO, show_atmaddress, NULL);
+static DEVICE_ATTR(atmindex, S_IRUGO, show_atmindex, NULL);
 static DEVICE_ATTR(carrier, S_IRUGO, show_carrier, NULL);
 static DEVICE_ATTR(type, S_IRUGO, show_type, NULL);
 static DEVICE_ATTR(link_rate, S_IRUGO, show_link_rate, NULL);
@@ -106,6 +117,7 @@ static DEVICE_ATTR(link_rate, S_IRUGO, show_link_rate, NULL);
 static struct device_attribute *atm_attrs[] = {
 	&dev_attr_atmaddress,
 	&dev_attr_address,
+	&dev_attr_atmindex,
 	&dev_attr_carrier,
 	&dev_attr_type,
 	&dev_attr_link_rate,