tools/memory-model: Finish the removal of rb-dep, smp_read_barrier_depends(), and...
authorAlan Stern <stern@rowland.harvard.edu>
Wed, 7 Mar 2018 17:27:40 +0000 (09:27 -0800)
committerIngo Molnar <mingo@kernel.org>
Sat, 10 Mar 2018 09:22:23 +0000 (10:22 +0100)
commitbd5c0ba2cd78a4c116726ead84f8f37dc92d043e
tree96b7c86c9fd330c270d7d4296c7b88da1fc1df59
parentff1fe5e079730f138c98b268ce2e8482a1d954b4
tools/memory-model: Finish the removal of rb-dep, smp_read_barrier_depends(), and lockless_dereference()

Commit:

  bf28ae562744 ("tools/memory-model: Remove rb-dep, smp_read_barrier_depends, and lockless_dereference")

was merged too early, while it was still in RFC form.  This patch adds in
the missing pieces.

Akira pointed out some typos in the original patch, and he noted that
cheatsheet.txt should indicate that READ_ONCE() now implies an address
dependency.  Andrea suggested documenting the relationship betwwen
unsuccessful RMW operations and address dependencies.

Andrea pointed out that the macro for rcu_dereference() in linux.def
should now use the "once" annotation instead of "deref".  He also
suggested that the comments should mention commit:

  5a8897cc7631 ("locking/atomics/alpha: Add smp_read_barrier_depends() to _release()/_relaxed() atomics")

... as an important precursor, and he contributed commit:

  cb13b424e986 ("locking/xchg/alpha: Add unconditional memory barrier to cmpxchg()")

which is another prerequisite.

Suggested-by: Akira Yokosawa <akiyks@gmail.com>
Suggested-by: Andrea Parri <parri.andrea@gmail.com>
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
[ Fixed read_read_lock() typo reported by Akira. ]
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Andrea Parri <parri.andrea@gmail.com>
Acked-by: Akira Yokosawa <akiyks@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: boqun.feng@gmail.com
Cc: dhowells@redhat.com
Cc: j.alglave@ucl.ac.uk
Cc: linux-arch@vger.kernel.org
Cc: luc.maranget@inria.fr
Cc: npiggin@gmail.com
Cc: will.deacon@arm.com
Fixes: bf28ae562744 ("tools/memory-model: Remove rb-dep, smp_read_barrier_depends, and lockless_dereference")
Link: http://lkml.kernel.org/r/1520443660-16858-4-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
tools/memory-model/Documentation/cheatsheet.txt
tools/memory-model/Documentation/explanation.txt
tools/memory-model/linux-kernel.def