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Subject[tip:locking/core] tools/memory-model: Remove out-of-date comments and code from lock.cat
Commit-ID:  cee0321a404fe6b43d1f4364639c8ffe2f2b37d1
Gitweb: https://git.kernel.org/tip/cee0321a404fe6b43d1f4364639c8ffe2f2b37d1
Author: Alan Stern <stern@rowland.harvard.edu>
AuthorDate: Mon, 14 May 2018 16:33:53 -0700
Committer: Ingo Molnar <mingo@kernel.org>
CommitDate: Tue, 15 May 2018 08:11:18 +0200

tools/memory-model: Remove out-of-date comments and code from lock.cat

lock.cat contains old comments and code referring to the possibility
of LKR events that are not part of an RMW pair. This is a holdover
from when I though we might end up using LKR events to implement
spin_is_locked(). Reword the comments to remove this assumption and
replace domain(lk-rmw) in the code with LKR.

Tested-by: Andrea Parri <andrea.parri@amarulasolutions.com>
[ paulmck: Pulled as lock-nest into previous line as discussed. ]
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Akira Yokosawa <akiyks@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Boqun Feng <boqun.feng@gmail.com>
Cc: David Howells <dhowells@redhat.com>
Cc: Jade Alglave <j.alglave@ucl.ac.uk>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luc Maranget <luc.maranget@inria.fr>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Will Deacon <will.deacon@arm.com>
Cc: linux-arch@vger.kernel.org
Cc: parri.andrea@gmail.com
Link: http://lkml.kernel.org/r/1526340837-12222-15-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
---
tools/memory-model/lock.cat | 15 ++++++---------
1 file changed, 6 insertions(+), 9 deletions(-)

diff --git a/tools/memory-model/lock.cat b/tools/memory-model/lock.cat
index 7217cd4941a4..cd002a33ca8a 100644
--- a/tools/memory-model/lock.cat
+++ b/tools/memory-model/lock.cat
@@ -47,18 +47,15 @@ flag ~empty [M \ IW] ; loc ; [ALL-LOCKS] as mixed-lock-accesses
let lk-rmw = ([LKR] ; po-loc ; [LKW]) \ (po ; po)
let rmw = rmw | lk-rmw

+(* The litmus test is invalid if an LKR/LKW event is not part of an RMW pair *)
+flag ~empty LKW \ range(lk-rmw) as unpaired-LKW
+flag ~empty LKR \ domain(lk-rmw) as unpaired-LKR
+
(*
- * A paired LKR must always see an unlocked value; spin_lock() calls nested
+ * An LKR must always see an unlocked value; spin_lock() calls nested
* inside a critical section (for the same lock) always deadlock.
*)
-empty ([LKW] ; po-loc ; [domain(lk-rmw)]) \ (po-loc ; [UL] ; po-loc)
- as lock-nest
-
-(* The litmus test is invalid if an LKW event is not part of an RMW pair *)
-flag ~empty LKW \ range(lk-rmw) as unpaired-LKW
-
-(* This will be allowed if we implement spin_is_locked() *)
-flag ~empty LKR \ domain(lk-rmw) as unpaired-LKR
+empty ([LKW] ; po-loc ; [LKR]) \ (po-loc ; [UL] ; po-loc) as lock-nest

(* The final value of a spinlock should not be tested *)
flag ~empty [FW] ; loc ; [ALL-LOCKS] as lock-final
\
 
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