These files are about implementation of seqlock in userspace. The most important files about seqlock are include/barrier.h and include/seq.h． File barrier.h is the implementation of memory barrier in userspace. File seq.h is the impementation of seqlock in userspace. ##Preparation If you really want to know about what I do, you should learn what is seqlock and what is memeory barrier firstly. About seqlock, you can see https://en.wikipedia.org/wiki/Seqlock. About memory barrier, there is a paper that is very much to recommend, its name is Memory Barriers: a Hardware View for Software Hackers and you can get it from http://www.rdrop.com/users/paulmck/scalability/paper/whymb.2010.07.23a.pdf.
##Using Using write lock, you can put your critical code between write_seqlock(&seqlock) and write_sequnlock(&seqlock).
Using read lock, you can do as follow:
unsigned int start;
do{
start = read_seqbegin(&seqlock);
}while(read_seqretry(&seqlock, start));