[PATCH] net: swich device attribute creation to default attrs

Recent udev versions don't longer cover bad sysfs timing with built-in
logic. Explicit rules are required to do that. For net devices, the
following is needed:
  ACTION=="add", SUBSYSTEM=="net", WAIT_FOR_SYSFS="address"
to handle access to net device properties from an event handler without
races.

This patch changes the main net attributes to be created by the driver
core, which is done _before_ the event is sent out and will not require
the stat() loop of the WAIT_FOR_SYSFS key.
Signed-off-by: NKay Sievers <kay.sievers@suse.de>
Acked-by: NDavid S. Miller <davem@davemloft.net>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

net/core/net-sysfs.c

@@ -84,16 +84,11 @@ static ssize_t netdev_store(struct class_device *dev,
 	return ret;
 }
 
-/* generate a read-only network device class attribute */
-#define NETDEVICE_ATTR(field, format_string)				\
-NETDEVICE_SHOW(field, format_string)					\
-static CLASS_DEVICE_ATTR(field, S_IRUGO, show_##field, NULL)		\
-
-NETDEVICE_ATTR(addr_len, fmt_dec);
-NETDEVICE_ATTR(iflink, fmt_dec);
-NETDEVICE_ATTR(ifindex, fmt_dec);
-NETDEVICE_ATTR(features, fmt_long_hex);
-NETDEVICE_ATTR(type, fmt_dec);
+NETDEVICE_SHOW(addr_len, fmt_dec);
+NETDEVICE_SHOW(iflink, fmt_dec);
+NETDEVICE_SHOW(ifindex, fmt_dec);
+NETDEVICE_SHOW(features, fmt_long_hex);
+NETDEVICE_SHOW(type, fmt_dec);
 
 /* use same locking rules as GIFHWADDR ioctl's */
 static ssize_t format_addr(char *buf, const unsigned char *addr, int len)
@@ -136,10 +131,6 @@ static ssize_t show_carrier(struct class_device *dev, char *buf)
 	return -EINVAL;
 }
 
-static CLASS_DEVICE_ATTR(address, S_IRUGO, show_address, NULL);
-static CLASS_DEVICE_ATTR(broadcast, S_IRUGO, show_broadcast, NULL);
-static CLASS_DEVICE_ATTR(carrier, S_IRUGO, show_carrier, NULL);
-
 /* read-write attributes */
 NETDEVICE_SHOW(mtu, fmt_dec);
 
@@ -153,8 +144,6 @@ static ssize_t store_mtu(struct class_device *dev, const char *buf, size_t len)
 	return netdev_store(dev, buf, len, change_mtu);
 }
 
-static CLASS_DEVICE_ATTR(mtu, S_IRUGO | S_IWUSR, show_mtu, store_mtu);
-
 NETDEVICE_SHOW(flags, fmt_hex);
 
 static int change_flags(struct net_device *net, unsigned long new_flags)
@@ -167,8 +156,6 @@ static ssize_t store_flags(struct class_device *dev, const char *buf, size_t len
 	return netdev_store(dev, buf, len, change_flags);
 }
 
-static CLASS_DEVICE_ATTR(flags, S_IRUGO | S_IWUSR, show_flags, store_flags);
-
 NETDEVICE_SHOW(tx_queue_len, fmt_ulong);
 
 static int change_tx_queue_len(struct net_device *net, unsigned long new_len)
@@ -182,9 +169,6 @@ static ssize_t store_tx_queue_len(struct class_device *dev, const char *buf, siz
 	return netdev_store(dev, buf, len, change_tx_queue_len);
 }
 
-static CLASS_DEVICE_ATTR(tx_queue_len, S_IRUGO | S_IWUSR, show_tx_queue_len, 
-			 store_tx_queue_len);
-
 NETDEVICE_SHOW(weight, fmt_dec);
 
 static int change_weight(struct net_device *net, unsigned long new_weight)
@@ -198,24 +182,21 @@ static ssize_t store_weight(struct class_device *dev, const char *buf, size_t le
 	return netdev_store(dev, buf, len, change_weight);
 }
 
-static CLASS_DEVICE_ATTR(weight, S_IRUGO | S_IWUSR, show_weight, 
-			 store_weight);
-
-
-static struct class_device_attribute *net_class_attributes[] = {
-	&class_device_attr_ifindex,
-	&class_device_attr_iflink,
-	&class_device_attr_addr_len,
-	&class_device_attr_tx_queue_len,
-	&class_device_attr_features,
-	&class_device_attr_mtu,
-	&class_device_attr_flags,
-	&class_device_attr_weight,
-	&class_device_attr_type,
-	&class_device_attr_address,
-	&class_device_attr_broadcast,
-	&class_device_attr_carrier,
-	NULL
+static struct class_device_attribute net_class_attributes[] = {
+	__ATTR(addr_len, S_IRUGO, show_addr_len, NULL),
+	__ATTR(iflink, S_IRUGO, show_iflink, NULL),
+	__ATTR(ifindex, S_IRUGO, show_ifindex, NULL),
+	__ATTR(features, S_IRUGO, show_features, NULL),
+	__ATTR(type, S_IRUGO, show_type, NULL),
+	__ATTR(address, S_IRUGO, show_address, NULL),
+	__ATTR(broadcast, S_IRUGO, show_broadcast, NULL),
+	__ATTR(carrier, S_IRUGO, show_carrier, NULL),
+	__ATTR(mtu, S_IRUGO | S_IWUSR, show_mtu, store_mtu),
+	__ATTR(flags, S_IRUGO | S_IWUSR, show_flags, store_flags),
+	__ATTR(tx_queue_len, S_IRUGO | S_IWUSR, show_tx_queue_len,
+	       store_tx_queue_len),
+	__ATTR(weight, S_IRUGO | S_IWUSR, show_weight, store_weight),
+	{}
 };
 
 /* Show a given an attribute in the statistics group */
@@ -407,6 +388,7 @@ static void netdev_release(struct class_device *cd)
 static struct class net_class = {
 	.name = "net",
 	.release = netdev_release,
+	.class_dev_attrs = net_class_attributes,
 #ifdef CONFIG_HOTPLUG
 	.uevent = netdev_uevent,
 #endif
@@ -431,8 +413,6 @@ void netdev_unregister_sysfs(struct net_device * net)
 int netdev_register_sysfs(struct net_device *net)
 {
 	struct class_device *class_dev = &(net->class_dev);
-	int i;
-	struct class_device_attribute *attr;
 	int ret;
 
 	class_dev->class = &net_class;
@@ -442,12 +422,6 @@ int netdev_register_sysfs(struct net_device *net)
 	if ((ret = class_device_register(class_dev)))
 		goto out;
 
-	for (i = 0; (attr = net_class_attributes[i]) != NULL; i++) {
-		if ((ret = class_device_create_file(class_dev, attr)))
-		    goto out_unreg;
-	}
-
-
 	if (net->get_stats &&
 	    (ret = sysfs_create_group(&class_dev->kobj, &netstat_group)))
 		goto out_unreg;