The kernel development cycle has evolved so beautifully overtime that it has set an example in the open source world. Having contributed to the kernel I actually enjoyed learning about the whole development cycle. Terms like mainline kernel, rc, stable release, long-term support confused me a lot initially but with time I understood at least the basic work-flow.
Keeping in the mind the volume of code that sits inside the kernel, it is very difficult for a single person to inspect each and every part of the project perfectly. Hats off to Linus and people like Greg. To make the process easier (it looks easy :P), the kernel is broken down into subsystems with each subsystem having its own main developer or as generally said top level maintainer. These maintainers decide which patch goes to the mainline kernel.
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