[PATCH] rcu: add rcu_bh_sync torture type to rcutorture

Use the newly-generic synchronous deferred free function to implement torture
testing for rcu_bh using synchronize_rcu_bh rather than the asynchronous
call_rcu_bh.

Signed-off-by: Josh Triplett <josh@freedesktop.org>
Acked-by: Paul E. McKenney <paulmck@us.ibm.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

Documentation/RCU/torture.txt

@@ -55,8 +55,9 @@ test_no_idle_hz	Whether or not to test the ability of RCU to operate in
 
 torture_type	The type of RCU to test: "rcu" for the rcu_read_lock() API,
 		"rcu_sync" for rcu_read_lock() with synchronous reclamation,
-		"rcu_bh" for the rcu_read_lock_bh() API, and "srcu" for the
-		"srcu_read_lock()" API.
+		"rcu_bh" for the rcu_read_lock_bh() API, "rcu_bh_sync" for
+		rcu_read_lock_bh() with synchronous reclamation, and "srcu"
+		for the "srcu_read_lock()" API.
 
 verbose		Enable debug printk()s.  Default is disabled.
 

kernel/rcutorture.c

@@ -370,6 +370,19 @@ static struct rcu_torture_ops rcu_bh_ops = {
 	.name = "rcu_bh"
 };
 
+static struct rcu_torture_ops rcu_bh_sync_ops = {
+	.init = rcu_sync_torture_init,
+	.cleanup = NULL,
+	.readlock = rcu_bh_torture_read_lock,
+	.readdelay = rcu_read_delay,  /* just reuse rcu's version. */
+	.readunlock = rcu_bh_torture_read_unlock,
+	.completed = rcu_bh_torture_completed,
+	.deferredfree = rcu_sync_torture_deferred_free,
+	.sync = rcu_bh_torture_synchronize,
+	.stats = NULL,
+	.name = "rcu_bh_sync"
+};
+
 /*
  * Definitions for srcu torture testing.
  */
@@ -452,7 +465,8 @@ static struct rcu_torture_ops srcu_ops = {
 };
 
 static struct rcu_torture_ops *torture_ops[] =
-	{ &rcu_ops, &rcu_sync_ops, &rcu_bh_ops, &srcu_ops, NULL };
+	{ &rcu_ops, &rcu_sync_ops, &rcu_bh_ops, &rcu_bh_sync_ops, &srcu_ops,
+	  NULL };
 
 /*
  * RCU torture writer kthread.  Repeatedly substitutes a new structure