From: Paul E. McKenney Date: Sat, 1 Aug 2015 17:45:26 +0000 (-0700) Subject: documentation: No acquire/release for RCU readers X-Git-Tag: v4.4-rc1~158^2~2^2^2~4 X-Git-Url: http://git.ipfire.org/?a=commitdiff_plain;h=27566139b6e2f6cfe273e8bb0e538d7616c2ea00;p=thirdparty%2Fkernel%2Flinux.git documentation: No acquire/release for RCU readers Documentation/memory-barriers.txt calls out RCU as one of the sets of primitives associated with ACQUIRE and RELEASE. There really is an association in that rcu_assign_pointer() includes a RELEASE operation, but a quick read can convince people that rcu_read_lock() and rcu_read_unlock() have ACQUIRE and RELEASE semantics, which they do not. This commit therefore removes RCU from this list in order to avoid this confusion. Reported-by: Boqun Feng Signed-off-by: Paul E. McKenney Reviewed-by: Josh Triplett --- diff --git a/Documentation/memory-barriers.txt b/Documentation/memory-barriers.txt index 2ba8461b0631d..d336e4d420297 100644 --- a/Documentation/memory-barriers.txt +++ b/Documentation/memory-barriers.txt @@ -1789,7 +1789,6 @@ The Linux kernel has a number of locking constructs: (*) mutexes (*) semaphores (*) R/W semaphores - (*) RCU In all cases there are variants on "ACQUIRE" operations and "RELEASE" operations for each construct. These operations all imply certain barriers: