kernel printk

http://blog.csdn.net/iamonlyme/article/details/7082494

/*

 * Write out chars from start to end - 1 inclusive

 */

static void _call_console_drivers(unsigned start,

unsigned end, int msg_log_level)

{

if ((msg_log_level < console_loglevel || ignore_loglevel) &&

console_drivers && start != end) {

if ((start & LOG_BUF_MASK) > (end & LOG_BUF_MASK)) {

/* wrapped write */

__call_console_drivers(start & LOG_BUF_MASK,

log_buf_len);

__call_console_drivers(0, end & LOG_BUF_MASK);

} else {

__call_console_drivers(start, end);

}

}

}