[PATCH tip/core/rcu 19/23] rcu: Adjust for unconditional ->completed assignment

From: Paul E. McKenney
Date: Thu Aug 30 2012 - 14:22:26 EST


From: "Paul E. McKenney" <paulmck@xxxxxxxxxxxxxxxxxx>

Now that the rcu_node structures' ->completed fields are unconditionally
assigned at grace-period cleanup time, they should already have the
correct value for the new grace period at grace-period initialization
time. This commit therefore inserts a WARN_ON_ONCE() to verify this
invariant.

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
kernel/rcutree.c | 4 +++-
1 files changed, 3 insertions(+), 1 deletions(-)

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 1373388..86903df 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -1098,6 +1098,7 @@ static int rcu_gp_init(struct rcu_state *rsp)
rcu_preempt_check_blocked_tasks(rnp);
rnp->qsmask = rnp->qsmaskinit;
rnp->gpnum = rsp->gpnum;
+ WARN_ON_ONCE(rnp->completed != rsp->completed);
rnp->completed = rsp->completed;
if (rnp == rdp->mynode)
rcu_start_gp_per_cpu(rsp, rnp, rdp);
@@ -2795,7 +2796,8 @@ static void __init rcu_init_one(struct rcu_state *rsp,
raw_spin_lock_init(&rnp->fqslock);
lockdep_set_class_and_name(&rnp->fqslock,
&rcu_fqs_class[i], fqs[i]);
- rnp->gpnum = 0;
+ rnp->gpnum = rsp->gpnum;
+ rnp->completed = rsp->completed;
rnp->qsmask = 0;
rnp->qsmaskinit = 0;
rnp->grplo = j * cpustride;
--
1.7.8

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