From: Frederic Weisbecker <[email protected]> This commit sets SEGCBLIST_SOFTIRQ_ONLY once toggling is otherwise fully complete, allowing further RCU callback manipulation to be carried out locklessly and locally.
Cc: Josh Triplett <[email protected]> Cc: Steven Rostedt <[email protected]> Cc: Mathieu Desnoyers <[email protected]> Cc: Lai Jiangshan <[email protected]> Cc: Joel Fernandes <[email protected]> Cc: Neeraj Upadhyay <[email protected]> Cc: Thomas Gleixner <[email protected]> Inspired-by: Paul E. McKenney <[email protected]> Tested-by: Boqun Feng <[email protected]> Signed-off-by: Frederic Weisbecker <[email protected]> Signed-off-by: Paul E. McKenney <[email protected]> --- kernel/rcu/tree_plugin.h | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 35dc9b3..8641b72 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -2352,7 +2352,14 @@ static int __rcu_nocb_rdp_deoffload(struct rcu_data *rdp) */ rcu_nocb_lock_irqsave(rdp, flags); rcu_nocb_flush_bypass(rdp, NULL, jiffies); - rcu_nocb_unlock_irqrestore(rdp, flags); + rcu_segcblist_set_flags(cblist, SEGCBLIST_SOFTIRQ_ONLY); + /* + * With SEGCBLIST_SOFTIRQ_ONLY, we can't use + * rcu_nocb_unlock_irqrestore() anymore. Theoretically we + * could set SEGCBLIST_SOFTIRQ_ONLY with cb unlocked and IRQs + * disabled now, but let's be paranoid. + */ + raw_spin_unlock_irqrestore(&rdp->nocb_lock, flags); return ret; } -- 2.9.5
