rcutorture: Correctly handle grace-period sequence wrap

The new ->gq_seq grace-period sequence numbers must be shifted down,
which give artifacts when these numbers wrap.  This commit therefore
enables rcutorture and rcuperf to handle grace-period sequence numbers
even if they do wrap.  It does this by allowing a special subtraction
function to be specified, and this function subtracts before shifting.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>

1 files changed, 3 insertions, 3 deletions

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index cbf2bcde5e60..fa219eea0ae7 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -532,7 +532,7 @@ static int rcu_pending(void);
  */
 unsigned long rcu_get_gp_seq(void)
 {
-	return rcu_seq_ctr(READ_ONCE(rcu_state_p->gp_seq));
+	return READ_ONCE(rcu_state_p->gp_seq);
 }
 EXPORT_SYMBOL_GPL(rcu_get_gp_seq);
 
@@ -541,7 +541,7 @@ EXPORT_SYMBOL_GPL(rcu_get_gp_seq);
  */
 unsigned long rcu_sched_get_gp_seq(void)
 {
-	return rcu_seq_ctr(READ_ONCE(rcu_sched_state.gp_seq));
+	return READ_ONCE(rcu_sched_state.gp_seq);
 }
 EXPORT_SYMBOL_GPL(rcu_sched_get_gp_seq);
 
@@ -550,7 +550,7 @@ EXPORT_SYMBOL_GPL(rcu_sched_get_gp_seq);
  */
 unsigned long rcu_bh_get_gp_seq(void)
 {
-	return rcu_seq_ctr(READ_ONCE(rcu_bh_state.gp_seq));
+	return READ_ONCE(rcu_bh_state.gp_seq);
 }
 EXPORT_SYMBOL_GPL(rcu_bh_get_gp_seq);