printk_parse_prefix
printk_parse_prefix(entry->level, &level, &flags);
prefix_len = printk_parse_prefix(entry->fmt, &level, &flags);
u16 printk_parse_prefix(const char *text, int *level,
prefix_len = printk_parse_prefix(text, NULL, NULL);
printk_parse_prefix(&prefix_buf[0], &level, &flags);