4.19-stable review patch. If anyone has any objections, please let me know.
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From: Pavel Machek pavel@ucw.cz
[ 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@ucw.cz Stable-dep-of: ff50f5327613 ("leds: trigger: ledtrig-cpu:: Fix 'output may be truncated' issue for 'cpu'") Signed-off-by: Sasha Levin sashal@kernel.org --- 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@linaro.org * Copyright 2011 - 2012 Bryan Wu bryan.wu@canonical.com @@ -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);