From: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Date: Wed, 29 Jun 2016 21:34:59 +0000 (-0700)
Subject: rcu: Stop disabling expedited RCU CPU stall warnings
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=908d2c1fd156d414008e1b7e1fb5a7716e013231;p=linux-beck.git

rcu: Stop disabling expedited RCU CPU stall warnings

Now that RCU expedited grace periods are always driven by a workqueue,
there is no need to account for signal reception, and thus no need
to disable expedited RCU CPU stall warnings due to signal reception.
This commit therefore removes the signal-reception checks, leaving a
WARN_ON() to catch possible future bugs.

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

diff --git a/kernel/rcu/tree_exp.h b/kernel/rcu/tree_exp.h
index 97f5ffe42b58..3a647eb96f23 100644
--- a/kernel/rcu/tree_exp.h
+++ b/kernel/rcu/tree_exp.h
@@ -427,12 +427,7 @@ static void synchronize_sched_expedited_wait(struct rcu_state *rsp)
 				jiffies_stall);
 		if (ret > 0 || sync_rcu_preempt_exp_done(rnp_root))
 			return;
-		if (ret < 0) {
-			/* Hit a signal, disable CPU stall warnings. */
-			swait_event(rsp->expedited_wq,
-				   sync_rcu_preempt_exp_done(rnp_root));
-			return;
-		}
+		WARN_ON(ret < 0);  /* workqueues should not be signaled. */
 		pr_err("INFO: %s detected expedited stalls on CPUs/tasks: {",
 		       rsp->name);
 		ndetected = 0;