printk_once(): use bool for boolean flag

Using the type bool (instead of int) for the __print_once flag in the
printk_once() macro matches the intent of the code better, and allows the
compiler to generate smaller code; eg a typical callsite with gcc 4.3.3 on
i386:

add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-6 (-6)
function                                     old     new   delta
static.__print_once                            4       1      -3
get_cpu_vendor                               146     143      -3

Saving 6 bytes of object size per callsite by slightly improving the
readability of the source seems like a win to me.

Signed-off-by: Roland Dreier <rolandd@cisco.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/include/linux/kernel.h b/include/linux/kernel.h
index 0a2a19087863da6ebe8a44a8394895b2d958700d..55723afa097bac9477d187b7a38a2a498751c918 100644 (file)
--- a/include/linux/kernel.h
+++ b/include/linux/kernel.h
@@ -252,10 +252,10 @@ extern int printk_delay_msec;
  * Print a one-time message (analogous to WARN_ONCE() et al):
  */
 #define printk_once(x...) ({                   \
-       static int __print_once = 1;            \
+       static bool __print_once = true;        \
                                                \
        if (__print_once) {                     \
-               __print_once = 0;               \
+               __print_once = false;           \
                printk(x);                      \
        }                                       \
 })