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qos: Don't allow userspace to impose restrictions on CPU idle levels

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Giving userspace intimate control over CPU latency requirements is
nonsense. Userspace can't even stop itself from being preempted, so
there's no reason for it to have access to a mechanism primarily used to
eliminate CPU delays on the order of microseconds.

Remove userspace's ability to send pm_qos requests so that it can't hurt
power consumption.

Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
Signed-off-by: Panchajanya1999 <kernel@panchajanya.dev>
This commit is contained in:
Sultan Alsawaf 2023-01-14 18:37:30 +05:30 committed by Ksawlii
parent 74cbd01416
commit 25da1fb9b2
1 changed files with 3 additions and 0 deletions
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kernel/power/qos.c
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@ -380,6 +380,9 @@ static ssize_t cpu_latency_qos_write(struct file *filp, const char __user *buf,
{
s32 value;
/* Don't let userspace impose restrictions on CPU idle levels */
return count;
if (count == sizeof(s32)) {
if (copy_from_user(&value, buf, sizeof(s32)))
return -EFAULT;