linux-kernel - [tip:locking/core] tools/memory-model: Remove out-of-date comments and code from lock.cat

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Date:   Mon, 14 May 2018 23:34:19 -0700
From:   tip-bot for Alan Stern <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     paulmck@...ux.vnet.ibm.com, andrea.parri@...rulasolutions.com,
        boqun.feng@...il.com, stern@...land.harvard.edu,
        j.alglave@....ac.uk, hpa@...or.com, akpm@...ux-foundation.org,
        linux-kernel@...r.kernel.org, torvalds@...ux-foundation.org,
        dhowells@...hat.com, mingo@...nel.org, luc.maranget@...ia.fr,
        tglx@...utronix.de, npiggin@...il.com, peterz@...radead.org,
        akiyks@...il.com, will.deacon@....com
Subject: [tip:locking/core] tools/memory-model: Remove out-of-date comments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@...land.harvard.edu>
AuthorDate: Mon, 14 May 2018 16:33:53 -0700
Committer:  Ingo Molnar <mingo@...nel.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tools/memory-model: Remove out-of-date comments and code from lock.cat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@...rulasolutions.com>
[ paulmck: Pulled as lock-nest into previous line as discussed. ]
Signed-off-by: Alan Stern <stern@...land.harvard.edu>
Signed-off-by: Paul E. McKenney <paulmck@...ux.vnet.ibm.com>
Cc: Akira Yokosawa <akiyks@...il.com>
Cc: Andrew Morton <akpm@...ux-foundation.org>
Cc: Boqun Feng <boqun.feng@...il.com>
Cc: David Howells <dhowells@...hat.com>
Cc: Jade Alglave <j.alglave@....ac.uk>
Cc: Linus Torvalds <torvalds@...ux-foundation.org>
Cc: Luc Maranget <luc.maranget@...ia.fr>
Cc: Nicholas Piggin <npiggin@...il.com>
Cc: Peter Zijlstra <peterz@...radead.org>
Cc: Thomas Gleixner <tglx@...utronix.de>
Cc: Will Deacon <will.deacon@....com>
Cc: linux-arch@...r.kernel.org
Cc: parri.andrea@...il.com
Link: http://lkml.kernel.org/r/1526340837-12222-15-git-send-email-paulmck@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar <mingo@...nel.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