In process of  exploring whatever corner of Linux kernel source tree it is cute to consult the sources using some automated search system. Cross reference Linux Project provides a good solution of what you need.  It’s a versatile cross-referencing tool for relatively large code repositories.

So, LXR (formerly “the Linux Cross Referencer“) and some of its forks may be your good friend.  One instance can be found here http://lxr.linux.no

Google’ing after Linux Cross Reference Source phrase you will find some good sites where the kernel sources are indexed.

Good examples could be:

• http://www.linux-m32r.org/lxr/http/source
• http://users.sosdg.org/~qiyong/lxr/source/
• http://fxr.watson.org

Ups, that last link is devilish!

Basic things that you could do with a cross reference repository:

• search for a variable, macro, function name etc and find the places in kernel where it’s defined and used (Identifier search)
• search for a particular file name (file search)

and many more, depending of your current repository.