tools/memory-model: Rename some RCU relations

In preparation for adding support for SRCU, rename "crit" to
"rcu-rscs", rename "rscs" to "rcu-rscsi", and remove the restriction
to only the outermost level of nesting.

The name change is needed for disambiguating RCU read-side critical
sections from SRCU read-side critical sections.  Adding the "i" at the
end of "rcu-rscsi" emphasizes that the relation is inverted; it links
rcu_read_unlock() events to their corresponding preceding
rcu_read_lock() events.

The restriction to outermost nesting levels was never essential; it
was included mostly to show that it could be done.  Rather than add
equivalent unnecessary code for SRCU lock nesting, it seemed better to
remove the existing code.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Tested-by: Andrea Parri <andrea.parri@amarulasolutions.com>

tools/memory-model/linux-kernel.bell

@@ -34,7 +34,7 @@ enum Barriers = 'wmb (*smp_wmb*) ||
 instructions F[Barriers]
 
 (* Compute matching pairs of nested Rcu-lock and Rcu-unlock *)
-let matched = let rec
+let rcu-rscs = let rec
 	    unmatched-locks = Rcu-lock \ domain(matched)
 	and unmatched-unlocks = Rcu-unlock \ range(matched)
 	and unmatched = unmatched-locks | unmatched-unlocks
@@ -46,8 +46,5 @@ let matched = let rec
 	in matched
 
 (* Validate nesting *)
-flag ~empty Rcu-lock \ domain(matched) as unbalanced-rcu-locking
-flag ~empty Rcu-unlock \ range(matched) as unbalanced-rcu-locking
-
-(* Outermost level of nesting only *)
-let crit = matched \ (po^-1 ; matched ; po^-1)
+flag ~empty Rcu-lock \ domain(rcu-rscs) as unbalanced-rcu-locking
+flag ~empty Rcu-unlock \ range(rcu-rscs) as unbalanced-rcu-locking

tools/memory-model/linux-kernel.cat

@@ -95,7 +95,7 @@ acyclic pb as propagation
  * onward on the one hand and from the rcu_read_unlock() backwards on the
  * other hand.
  *)
-let rscs = po ; crit^-1 ; po?
+let rcu-rscsi = po ; rcu-rscs^-1 ; po?
 
 (*
  * The synchronize_rcu() strong fence is special in that it can order not
@@ -109,10 +109,10 @@ let rcu-link = hb* ; pb* ; prop
  * critical sections (joined by rcu-link) acts as a generalized strong fence.
  *)
 let rec rcu-fence = gp |
-	(gp ; rcu-link ; rscs) |
-	(rscs ; rcu-link ; gp) |
-	(gp ; rcu-link ; rcu-fence ; rcu-link ; rscs) |
-	(rscs ; rcu-link ; rcu-fence ; rcu-link ; gp) |
+	(gp ; rcu-link ; rcu-rscsi) |
+	(rcu-rscsi ; rcu-link ; gp) |
+	(gp ; rcu-link ; rcu-fence ; rcu-link ; rcu-rscsi) |
+	(rcu-rscsi ; rcu-link ; rcu-fence ; rcu-link ; gp) |
 	(rcu-fence ; rcu-link ; rcu-fence)
 
 (* rb orders instructions just as pb does *)