[PATCH] Remove grace-period machinery from rcutree __call_rcu()

[Paul E . McKenney]

The grace-period machinery in __call_rcu() was a failed attempt to avoid
implementing synchronize_rcu_expedited().  But now that this attempt has
failed, try removing the machinery.

Signed-off-by: Paul E. McKenney <paulmck@xxxxxxxxxxxxxxxxxx>
---
 kernel/rcutree.c |   12 ------------
 1 files changed, 0 insertions(+), 12 deletions(-)

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index d2a372f..104de9e 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -1201,26 +1201,14 @@ __call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu),
 	 */
 	local_irq_save(flags);
 	rdp = rsp->rda[smp_processor_id()];
-	rcu_process_gp_end(rsp, rdp);
-	check_for_new_grace_period(rsp, rdp);
 
 	/* Add the callback to our list. */
 	*rdp->nxttail[RCU_NEXT_TAIL] = head;
 	rdp->nxttail[RCU_NEXT_TAIL] = &head->next;
 
-	/* Start a new grace period if one not already started. */
-	if (ACCESS_ONCE(rsp->completed) == ACCESS_ONCE(rsp->gpnum)) {
-		unsigned long nestflag;
-		struct rcu_node *rnp_root = rcu_get_root(rsp);
-
-		spin_lock_irqsave(&rnp_root->lock, nestflag);
-		rcu_start_gp(rsp, nestflag);  /* releases rnp_root->lock. */
-	}
-
 	/* Force the grace period if too many callbacks or too long waiting. */
 	if (unlikely(++rdp->qlen > qhimark)) {
 		rdp->blimit = LONG_MAX;
-		force_quiescent_state(rsp, 0);
 	} else if ((long)(ACCESS_ONCE(rsp->jiffies_force_qs) - jiffies) < 0)
 		force_quiescent_state(rsp, 1);
 	local_irq_restore(flags);
-- 
1.5.2.5

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