Patch "ledtrig-cpu: Limit to 8 CPUs" has been added to the 5.4-stable tree

[Sasha Levin <sashal@xxxxxxxxxx>]

This is a note to let you know that I've just added the patch titled

    ledtrig-cpu: Limit to 8 CPUs

to the 5.4-stable tree which can be found at:
    http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
     ledtrig-cpu-limit-to-8-cpus.patch
and it can be found in the queue-5.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.



commit 308e2dd197686bef838a7fdab8d52fea144ffc85
Author: Pavel Machek <pavel@xxxxxx>
Date:   Sat Sep 19 11:34:58 2020 +0200

    ledtrig-cpu: Limit to 8 CPUs
    
    [ 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>

diff --git a/drivers/leds/trigger/ledtrig-cpu.c b/drivers/leds/trigger/ledtrig-cpu.c
index 869976d1b734e..fca62d5035909 100644
--- a/drivers/leds/trigger/ledtrig-cpu.c
+++ b/drivers/leds/trigger/ledtrig-cpu.c
@@ -2,14 +2,18 @@
 /*
  * 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>
@@ -145,6 +149,9 @@ 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);