[PATCH] rcutorture: add call_rcu_bh() operations

Add operations for the call_rcu_bh() variant of RCU.  Also add an
rcu_batches_completed_bh() function, which is needed by rcutorture.

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

include/linux/rcupdate.h

@@ -258,6 +258,7 @@ extern void rcu_init(void);
 extern void rcu_check_callbacks(int cpu, int user);
 extern void rcu_restart_cpu(int cpu);
 extern long rcu_batches_completed(void);
+extern long rcu_batches_completed_bh(void);
 
 /* Exported interfaces */
 extern void FASTCALL(call_rcu(struct rcu_head *head, 

kernel/rcupdate.c

@@ -182,6 +182,15 @@ long rcu_batches_completed(void)
 	return rcu_ctrlblk.completed;
 }
 
+/*
+ * Return the number of RCU batches processed thus far.  Useful
+ * for debug and statistics.
+ */
+long rcu_batches_completed_bh(void)
+{
+	return rcu_bh_ctrlblk.completed;
+}
+
 static void rcu_barrier_callback(struct rcu_head *notused)
 {
 	if (atomic_dec_and_test(&rcu_barrier_cpu_count))
@@ -619,6 +628,7 @@ module_param(qlowmark, int, 0);
 module_param(rsinterval, int, 0);
 #endif
 EXPORT_SYMBOL_GPL(rcu_batches_completed);
+EXPORT_SYMBOL_GPL(rcu_batches_completed_bh);
 EXPORT_SYMBOL_GPL(call_rcu);
 EXPORT_SYMBOL_GPL(call_rcu_bh);
 EXPORT_SYMBOL_GPL(synchronize_rcu);

kernel/rcutorture.c

@@ -66,7 +66,7 @@ MODULE_PARM_DESC(test_no_idle_hz, "Test support for tickless idle CPUs");
 module_param(shuffle_interval, int, 0);
 MODULE_PARM_DESC(shuffle_interval, "Number of seconds between shuffles");
 module_param(torture_type, charp, 0);
-MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu)");
+MODULE_PARM_DESC(torture_type, "Type of RCU to torture (rcu, rcu_bh)");
 
 #define TORTURE_FLAG "-torture:"
 #define PRINTK_STRING(s) \
@@ -246,8 +246,44 @@ static struct rcu_torture_ops rcu_ops = {
 	.name = "rcu"
 };
 
+/*
+ * Definitions for rcu_bh torture testing.
+ */
+
+static int rcu_bh_torture_read_lock(void)
+{
+	rcu_read_lock_bh();
+	return 0;
+}
+
+static void rcu_bh_torture_read_unlock(int idx)
+{
+	rcu_read_unlock_bh();
+}
+
+static int rcu_bh_torture_completed(void)
+{
+	return rcu_batches_completed_bh();
+}
+
+static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
+{
+	call_rcu_bh(&p->rtort_rcu, rcu_torture_cb);
+}
+
+static struct rcu_torture_ops rcu_bh_ops = {
+	.init = NULL,
+	.cleanup = NULL,
+	.readlock = rcu_bh_torture_read_lock,
+	.readunlock = rcu_bh_torture_read_unlock,
+	.completed = rcu_bh_torture_completed,
+	.deferredfree = rcu_bh_torture_deferred_free,
+	.stats = NULL,
+	.name = "rcu_bh"
+};
+
 static struct rcu_torture_ops *torture_ops[] =
-	{ &rcu_ops, NULL };
+	{ &rcu_ops, &rcu_bh_ops, NULL };
 
 /*
  * RCU torture writer kthread.  Repeatedly substitutes a new structure