workqueue: skip the node_nr_active update for non-unbound workqueuesgrafted

apply_wqattrs_commit() updates node_nr_active->max unconditionally.
wq->node_nr_active[] is only allocated for unbound workqueues, so guard
the call before per-cpu workqueues start using this path.

No functional change: only unbound workqueues reach apply_wqattrs_*()
today.

Signed-off-by: Breno Leitao <leitao@debian.org>
Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 26 insertions, 0 deletions

diff --git a/lib/math/lcm.c b/lib/math/lcm.c
new file mode 100644
index 000000000..6e0b2e736
--- /dev/null
+++ b/lib/math/lcm.c
@@ -0,0 +1,26 @@
+// SPDX-License-Identifier: GPL-2.0-only
+#include <linux/compiler.h>
+#include <linux/gcd.h>
+#include <linux/export.h>
+#include <linux/lcm.h>
+
+/* Lowest common multiple */
+unsigned long lcm(unsigned long a, unsigned long b)
+{
+	if (a && b)
+		return (a / gcd(a, b)) * b;
+	else
+		return 0;
+}
+EXPORT_SYMBOL_GPL(lcm);
+
+unsigned long lcm_not_zero(unsigned long a, unsigned long b)
+{
+	unsigned long l = lcm(a, b);
+
+	if (l)
+		return l;
+
+	return (b ? : a);
+}
+EXPORT_SYMBOL_GPL(lcm_not_zero);