From: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Date: Tue, 10 Mar 2015 00:00:56 +0000 (-0700)
Subject: rcu: Remove redundant offline check
X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=cce7f1fc015a98ca9263bd5730c00258bc214e53;p=GitHub%2FLineageOS%2FG12%2Fandroid_kernel_amlogic_linux-4.9.git

rcu: Remove redundant offline check

Because offline CPUs are propagated up the rcu_node tree's ->qsmaskinit
bits just before each grace period starts, the ->qsmaskinit bit cannot
be clear when the corresponding ->qsmask bit is set.  Furthermore, this
condition used to correspond to a CPU that was on its way offline, and
making RCU's notion of an offline CPU more precise has eliminated this
situation.  This commit therefore removes the now-redundant offline
check from force_qs_rnp().

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

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index e338a12c3a1b..a1df68fce545 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -2749,8 +2749,6 @@ static void force_qs_rnp(struct rcu_state *rsp,
 		bit = 1;
 		for (; cpu <= rnp->grphi; cpu++, bit <<= 1) {
 			if ((rnp->qsmask & bit) != 0) {
-				if ((rnp->qsmaskinit & bit) == 0)
-					*isidle = false; /* Pending hotplug. */
 				if (f(per_cpu_ptr(rsp->rda, cpu), isidle, maxj))
 					mask |= bit;
 			}