Bluetooth: Add bt_printk

Add a local logging function to emit bluetooth specific
messages.  Using vsprintf extension %pV saves code/text
space.

Convert the current BT_INFO and BT_ERR macros to use bt_printk.
Remove __func__ from BT_ERR macro (and the uses).
Prefix "Bluetooth: " to BT_ERR
Remove __func__ from BT_DBG as function can be prefixed when
using dynamic_debug.

With allyesconfig:

   text    data     bss     dec     hex filename
 129956    8632   36096  174684   2aa5c drivers/bluetooth/built-in.o.new2
 134402    8632   36064  179098   2bb9a drivers/bluetooth/built-in.o.old
  14778    1012    3408   19198    4afe net/bluetooth/bnep/built-in.o.new2
  15067    1012    3408   19487    4c1f net/bluetooth/bnep/built-in.o.old
 346595   19163   86080  451838   6e4fe net/bluetooth/built-in.o.new2
 353751   19163   86064  458978   700e2 net/bluetooth/built-in.o.old
  18483    1172    4264   23919    5d6f net/bluetooth/cmtp/built-in.o.new2
  18927    1172    4264   24363    5f2b net/bluetooth/cmtp/built-in.o.old
  19237    1172    5152   25561    63d9 net/bluetooth/hidp/built-in.o.new2
  19581    1172    5152   25905    6531 net/bluetooth/hidp/built-in.o.old
  59461    3884   14464   77809   12ff1 net/bluetooth/rfcomm/built-in.o.new2
  61206    3884   14464   79554   136c2 net/bluetooth/rfcomm/built-in.o.old

with x86 defconfig (and just bluetooth):

$ size net/bluetooth/built-in.o.defconfig.*
   text    data     bss     dec     hex filename
  66358     933     100   67391   1073f net/bluetooth/built-in.o.defconfig.new
  66643     933     100   67676   1085c net/bluetooth/built-in.o.defconfig.old
Signed-off-by: Joe Perches <joe@perches.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>

include/net/bluetooth/bluetooth.h

@@ -76,9 +76,12 @@ struct bt_power {
 #define BT_POWER_FORCE_ACTIVE_OFF 0
 #define BT_POWER_FORCE_ACTIVE_ON  1
 
-#define BT_INFO(fmt, arg...) printk(KERN_INFO "Bluetooth: " fmt "\n" , ## arg)
-#define BT_ERR(fmt, arg...)  printk(KERN_ERR "%s: " fmt "\n" , __func__ , ## arg)
-#define BT_DBG(fmt, arg...)  pr_debug("%s: " fmt "\n" , __func__ , ## arg)
+__attribute__((format (printf, 2, 3)))
+int bt_printk(const char *level, const char *fmt, ...);
+
+#define BT_INFO(fmt, arg...)   bt_printk(KERN_INFO, pr_fmt(fmt), ##arg)
+#define BT_ERR(fmt, arg...)    bt_printk(KERN_ERR, pr_fmt(fmt), ##arg)
+#define BT_DBG(fmt, arg...)    pr_debug(fmt "\n", ##arg)
 
 /* Connection and socket states */
 enum {

net/bluetooth/lib.c

@@ -150,3 +150,22 @@ int bt_to_errno(__u16 code)
 	}
 }
 EXPORT_SYMBOL(bt_to_errno);
+
+int bt_printk(const char *level, const char *format, ...)
+{
+	struct va_format vaf;
+	va_list args;
+	int r;
+
+	va_start(args, format);
+
+	vaf.fmt = format;
+	vaf.va = &args;
+
+	r = printk("%sBluetooth: %pV\n", level, &vaf);
+
+	va_end(args);
+
+	return r;
+}
+EXPORT_SYMBOL(bt_printk);