Paul Heidekrüger pointed out that the Linux Kernel Memory Model documentation doesn't mention the distinction between syntactic and semantic dependencies. This is an important difference, because the compiler can easily break dependencies that are only syntactic, not semantic. This patch adds a few paragraphs to the LKMM documentation explaining these issues and illustrating how they can matter. Suggested-by: Paul Heidekrüger <paul.heidekrueger@in.tum.de> Reviewed-by: Akira Yokosawa <akiyks@gmail.com> Signed-off-by: Alan Stern <stern@rowland.harvard.edu> Signed-off-by: Paul E. McKenney <paulmck@kernel.org>