wext: add back wireless/ dir in sysfs for cfg80211 interfaces

The move away from having drivers assign wireless handlers,
in favour of making cfg80211 assign them, broke the sysfs
registration (the wireless/ dir went missing) because the
handlers are now assigned only after registration, which is
too late.

Fix this by special-casing cfg80211-based devices, all
of which are required to have an ieee80211_ptr, in the
sysfs code, and also using get_wireless_stats() to have
the same values reported as in procfs.
Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Reported-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Tested-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

include/net/wext.h

@@ -14,6 +14,7 @@ extern int wext_handle_ioctl(struct net *net, struct ifreq *ifr, unsigned int cm
 			     void __user *arg);
 extern int compat_wext_handle_ioctl(struct net *net, unsigned int cmd,
 				    unsigned long arg);
+extern struct iw_statistics *get_wireless_stats(struct net_device *dev);
 #else
 static inline int wext_proc_init(struct net *net)
 {

net/core/net-sysfs.c

@@ -16,7 +16,7 @@
 #include <net/sock.h>
 #include <linux/rtnetlink.h>
 #include <linux/wireless.h>
-#include <net/iw_handler.h>
+#include <net/wext.h>
 
 #include "net-sysfs.h"
 
@@ -363,15 +363,13 @@ static ssize_t wireless_show(struct device *d, char *buf,
 					       char *))
 {
 	struct net_device *dev = to_net_dev(d);
-	const struct iw_statistics *iw = NULL;
+	const struct iw_statistics *iw;
 	ssize_t ret = -EINVAL;
 
 	read_lock(&dev_base_lock);
 	if (dev_isalive(dev)) {
-		if (dev->wireless_handlers &&
-		    dev->wireless_handlers->get_wireless_stats)
-			iw = dev->wireless_handlers->get_wireless_stats(dev);
-		if (iw != NULL)
+		iw = get_wireless_stats(dev);
+		if (iw)
 			ret = (*format)(iw, buf);
 	}
 	read_unlock(&dev_base_lock);
@@ -505,7 +503,7 @@ int netdev_register_kobject(struct net_device *net)
 	*groups++ = &netstat_group;
 
 #ifdef CONFIG_WIRELESS_EXT_SYSFS
-	if (net->wireless_handlers && net->wireless_handlers->get_wireless_stats)
+	if (net->wireless_handlers || net->ieee80211_ptr)
 		*groups++ = &wireless_group;
 #endif
 #endif /* CONFIG_SYSFS */

net/wireless/wext.c

@@ -470,7 +470,7 @@ static iw_handler get_handler(struct net_device *dev, unsigned int cmd)
 /*
  * Get statistics out of the driver
  */
-static struct iw_statistics *get_wireless_stats(struct net_device *dev)
+struct iw_statistics *get_wireless_stats(struct net_device *dev)
 {
 	/* New location */
 	if ((dev->wireless_handlers != NULL) &&