Linux kernel space and user space communication

http://www.cnblogs.com/innost/archive/2011/01/09/1931456.html
http://blog.csdn.net/luoshengyang/article/details/6618363/
http://blog.csdn.net/luoshengyang/article/details/6703247
http://blog.csdn.net/stonecao/article/details/6591847

http://blog.csdn.net/wwj_748/article/details/8927784