rcu: Make force_quiescent_state() start grace period if needed

[firefly-linux-kernel-4.4.55.git] / kernel / rcutree.c

diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index d9202857d3adbc6d2fada5e3c401c4767ba2fbbd..55e8f6ef8195788a0bff13e76fadda70264ea7c5 100644 (file)
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -660,6 +660,8 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags)
        struct rcu_node *rnp = rcu_get_root(rsp);
 
        if (!cpu_needs_another_gp(rsp, rdp) || rsp->fqs_active) {
+               if (cpu_needs_another_gp(rsp, rdp))
+                       rsp->fqs_need_gp = 1;
                if (rnp->completed == rsp->completed) {
                        spin_unlock_irqrestore(&rnp->lock, flags);
                        return;
@@ -1239,6 +1241,12 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
                break;
        }
        rsp->fqs_active = 0;
+       if (rsp->fqs_need_gp) {
+               spin_unlock(&rsp->fqslock); /* irqs remain disabled */
+               rsp->fqs_need_gp = 0;
+               rcu_start_gp(rsp, flags); /* releases rnp->lock */
+               return;
+       }
        spin_unlock(&rnp->lock);  /* irqs remain disabled */
 unlock_fqs_ret:
        spin_unlock_irqrestore(&rsp->fqslock, flags);