4.19-stable review patch. If anyone has any objections, please let me know.
------------------
From: Pavel Machek <pavel@xxxxxx>
[ Upstream commit abcc131292aa8c7de2c5f0ed76a717436c21de63 ]
Some machines have thousands of CPUs... and trigger mechanisms was not
really meant for thousands of triggers. I doubt anyone uses this
trigger on many-CPU machine; but if they do, they'll need to do it
properly.
Signed-off-by: Pavel Machek <pavel@xxxxxx>
Stable-dep-of: ff50f5327613 ("leds: trigger: ledtrig-cpu:: Fix 'output may be truncated' issue for 'cpu'")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/leds/trigger/ledtrig-cpu.c | 13 ++++++++++---
1 file changed, 10 insertions(+), 3 deletions(-)
diff --git a/drivers/leds/trigger/ledtrig-cpu.c b/drivers/leds/trigger/ledtrig-cpu.c
index 66a6260919367..1fca1ad00c3b9 100644
--- a/drivers/leds/trigger/ledtrig-cpu.c
+++ b/drivers/leds/trigger/ledtrig-cpu.c
@@ -1,14 +1,18 @@
/*
* ledtrig-cpu.c - LED trigger based on CPU activity
*
- * This LED trigger will be registered for each possible CPU and named as
- * cpu0, cpu1, cpu2, cpu3, etc.
+ * This LED trigger will be registered for first 8 CPUs and named
+ * as cpu0..cpu7. There's additional trigger called cpu that
+ * is on when any CPU is active.
+ *
+ * If you want support for arbitrary number of CPUs, make it one trigger,
+ * with additional sysfs file selecting which CPU to watch.
*
* It can be bound to any LED just like other triggers using either a
* board file or via sysfs interface.
*
* An API named ledtrig_cpu is exported for any user, who want to add CPU
- * activity indication in their code
+ * activity indication in their code.
*
* Copyright 2011 Linus Walleij <linus.walleij@xxxxxxxxxx>
* Copyright 2011 - 2012 Bryan Wu <bryan.wu@xxxxxxxxxxxxx>
@@ -149,6 +153,9 @@ static int __init ledtrig_cpu_init(void)
for_each_possible_cpu(cpu) {
struct led_trigger_cpu *trig = &per_cpu(cpu_trig, cpu);
+ if (cpu >= 8)
+ continue;
+
snprintf(trig->name, MAX_NAME_LEN, "cpu%d", cpu);
led_trigger_register_simple(trig->name, &trig->_trig);
--
2.42.0
