To set your tabs in emacs to the correct C style, add the following to your .emacs file:
(defun linux-c-mode ()
  "C mode with adjusted defaults for use with the Linux kernel."
  (interactive)
  (c-mode)
  (c-set-style "K&R")
  (setq c-basic-offset 8))
When you enter emacs, you can then type:
	M-x linux-c-mode
OR you can put the following string in a comment at the start of the file:
/* -*- linux-c -*- */
More information about emacs and tabs may be found at http://www-2.cs.cmu.edu/cgi-bin/info2www?(emacs)Custom%20C%20Indent