tun: get rid of DBG1() macro

This macro is no-op unless TUN_DEBUG is defined (which requires editing and
recompiling the source) and only does something if variable debug is 2 but
that variable is zero initialized and never set to anything else. Moreover,
the only use of the macro informs about entering function tun_chr_open()
which can be easily achieved using ftrace or kprobe.

Drop DBG1() macro, its only use and global variable debug.
Signed-off-by: Michal Kubecek <mkubecek@suse.cz>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/tun.c

@@ -79,29 +79,17 @@ static void tun_default_link_ksettings(struct net_device *dev,
 /* #define TUN_DEBUG 1 */
 
 #ifdef TUN_DEBUG
-static int debug;
-
 #define tun_debug(level, tun, fmt, args...)			\
 do {								\
 	if (tun->debug)						\
 		netdev_printk(level, tun->dev, fmt, ##args);	\
 } while (0)
-#define DBG1(level, fmt, args...)				\
-do {								\
-	if (debug == 2)						\
-		printk(level fmt, ##args);			\
-} while (0)
 #else
 #define tun_debug(level, tun, fmt, args...)			\
 do {								\
 	if (0)							\
 		netdev_printk(level, tun->dev, fmt, ##args);	\
 } while (0)
-#define DBG1(level, fmt, args...)				\
-do {								\
-	if (0)							\
-		printk(level fmt, ##args);			\
-} while (0)
 #endif
 
 #define TUN_RX_PAD (NET_IP_ALIGN + NET_SKB_PAD)
@@ -3415,8 +3403,6 @@ static int tun_chr_open(struct inode *inode, struct file * file)
 	struct net *net = current->nsproxy->net_ns;
 	struct tun_file *tfile;
 
-	DBG1(KERN_INFO, "tunX: tun_chr_open\n");
-
 	tfile = (struct tun_file *)sk_alloc(net, AF_UNSPEC, GFP_KERNEL,
 					    &tun_proto, 0);
 	if (!tfile)