wext: make sysfs bits optional and deprecate them

The /sys/class/net/*/wireless/ direcory is, as far as I know, not
used by anyone. Additionally, the same data is available via wext
ioctls. Hence the sysfs files are pretty much useless. This patch
makes them optional and schedules them for removal.

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Cc: Jean Tourrilhes <jt@hpl.hp.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

Documentation/feature-removal-schedule.txt

@@ -333,3 +333,13 @@ Why:	This option was introduced just to allow older lm-sensors userspace
 	to keep working over the upgrade to 2.6.26. At the scheduled time of
 	removal fixed lm-sensors (2.x or 3.x) should be readily available.
 Who:	Rene Herman <rene.herman@gmail.com>
+
+---------------------------
+
+What:	Code that is now under CONFIG_WIRELESS_EXT_SYSFS
+	(in net/core/net-sysfs.c)
+When:	After the only user (hal) has seen a release with the patches
+	for enough time, probably some time in 2010.
+Why:	Over 1K .text/.data size reduction, data is available in other
+	ways (ioctls)
+Who:	Johannes Berg <johannes@sipsolutions.net>

net/core/net-sysfs.c

@@ -318,7 +318,7 @@ static struct attribute_group netstat_group = {
 	.attrs  = netstat_attrs,
 };
 
-#ifdef CONFIG_WIRELESS_EXT
+#ifdef CONFIG_WIRELESS_EXT_SYSFS
 /* helper function that does all the locking etc for wireless stats */
 static ssize_t wireless_show(struct device *d, char *buf,
 			     ssize_t (*format)(const struct iw_statistics *,
@@ -459,7 +459,7 @@ int netdev_register_kobject(struct net_device *net)
 #ifdef CONFIG_SYSFS
 	*groups++ = &netstat_group;
 
-#ifdef CONFIG_WIRELESS_EXT
+#ifdef CONFIG_WIRELESS_EXT_SYSFS
 	if (net->wireless_handlers && net->wireless_handlers->get_wireless_stats)
 		*groups++ = &wireless_group;
 #endif

net/wireless/Kconfig

@@ -29,3 +29,14 @@ config WIRELESS_EXT
 
 	  Say N (if you can) unless you know you need wireless
 	  extensions for external modules.
+
+config WIRELESS_EXT_SYSFS
+	bool "Wireless extensions sysfs files"
+	default y
+	depends on WIRELESS_EXT && SYSFS
+	help
+	  This option enables the deprecated wireless statistics
+	  files in /sys/class/net/*/wireless/. The same information
+	  is available via the ioctls as well.
+
+	  Say Y if you have programs using it (we don't know of any).