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From:   Qian Cai <cai@lca.pw>
To:     heiko.carstens@de.ibm.com, gor@linux.ibm.com,
        borntraeger@de.ibm.com
Cc:     linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org,
        Qian Cai <cai@lca.pw>
Subject: [PATCH] s390: set NODES_SHIFT=0 when NUMA=n
Date:   Tue,  9 Jun 2020 21:45:01 -0400
Message-Id: <20200610014501.4268-1-cai@lca.pw>
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When NUMA=n and nr_node_ids=2, in apply_wqattrs_prepare(), it has,

for_each_node(node) {
	if (wq_calc_node_cpumask(...

where it will trigger a booting warning,

WARNING: workqueue cpumask: online intersect > possible intersect

because it found 2 nodes and wq_numa_possible_cpumask[1] is an empty
cpumask. NUMA=y has no such problem because node_possible_map will be
initialized properly containing only node 0. Fix it by setting
NODES_SHIFT=0 when NUMA=n.

Fixes: 701dc81e7412 ("s390/mm: remove fake numa support")
Signed-off-by: Qian Cai <cai@lca.pw>
---
 arch/s390/Kconfig | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/arch/s390/Kconfig b/arch/s390/Kconfig
index f854faff38c3..59625356d18a 100644
--- a/arch/s390/Kconfig
+++ b/arch/s390/Kconfig
@@ -462,7 +462,8 @@ config NUMA
 
 config NODES_SHIFT
 	int
-	default "1"
+	default "1" if NUMA
+	default "0"
 
 config SCHED_SMT
 	def_bool n
-- 
2.21.0 (Apple Git-122.2)