[PATCH RFC LKMM 1/7] tools/memory-model: Rename some RCU relations

Paul E. McKenney
2019-01-09T21:08:38Z

From: Alan Stern <stern@rowland.harvard.edu>

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 | 9 +++------
tools/memory-model/linux-kernel.cat | 10 +++++-----
2 files changed, 8 insertions(+), 11 deletions(-)

diff --git a/tools/memory-model/linux-kernel.bell b/tools/memory-model/linux-kernel.bell
index 796513362c05..353c8d68e030 100644
--- a/tools/memory-model/linux-kernel.bell
+++ b/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
diff --git a/tools/memory-model/linux-kernel.cat b/tools/memory-model/linux-kernel.cat
index 8f23c74a96fd..ab9de9c1234b 100644
--- a/tools/memory-model/linux-kernel.cat
+++ b/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 *)
--
2.17.1