From: Paul E. McKenney Date: Tue, 24 Sep 2013 22:04:06 +0000 (-0700) Subject: rcu: Fix and comment ordering around wait_event() X-Git-Tag: v3.14-rc1~174^2^2^2~13 X-Git-Url: http://git.openpandora.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=78e4bc34e5d966cfd95f1238565afc399d56225c;p=pandora-kernel.git rcu: Fix and comment ordering around wait_event() It is all too easy to forget that wait_event() does not necessarily imply a full memory barrier. The case where it does not is where the condition transitions to true just as wait_event() starts execution. This is actually a feature: The standard use of wait_event() involves locking, in which case the locks provide the needed ordering (you hold a lock across the wake_up() and acquire that same lock after wait_event() returns). Given that I did forget that wait_event() does not necessarily imply a full memory barrier in one case, this commit fixes that case. This commit also adds comments calling out the placement of existing memory barriers relied on by wait_event() calls. Signed-off-by: Paul E. McKenney --- Reading git-diff-tree failed