kobjects and sysfs in a Nutshell
This chapter looked at the device model, sysfs, kobjects, and the kernel event layer. But a discussion on these topics drags in a plethora of their friends: We had to touch also on ksets, subsystems, attributes, ktypes, and krefs, to name a few. These structures are of different uses to different people. Driver writers need only a peripheral view of these topics. Most driver subsystems nicely hide the internals of kobjects and their friends. Understanding the basics and perhaps interfaces such as sysfs_create_file() is enough for a driver writer. Developers working on the core kernel, however, may need a more in-depth understanding of kobjects. kobjects are becoming sufficiently important that many of their users may not be working on drivers or driver subsystems at all!
This chapter discussed the last subsystem in the kernel that we will cover. The following chapters cover general but important topics that every kernel developer need know. First off, debugging!