kernel: Don't allow IRQ affinity masks to have more than one CPU

Even with an affinity mask that has multiple CPUs set, IRQs always run
on the first CPU in their affinity mask. Drivers that register an IRQ
affinity notifier (such as pm_qos) will therefore have an incorrect
assumption of where an IRQ is affined.

Fix the IRQ affinity mask deception by forcing it to only contain one
set CPU.

Change-Id: I12d28a061b6dc0dca0d04f703fbd77a6f0024d3d
Signed-off-by: Sultan Alsawaf <sultan@kerneltoast.com>
Signed-off-by: SamarV-121 <samarvispute121@gmail.com>
This commit is contained in:
Sultan Alsawaf 2019-05-25 22:48:20 -07:00 committed by prashantpaddune
parent 28bdcbbab1
commit 447af8c70b

View File

@ -214,6 +214,8 @@ int irq_do_set_affinity(struct irq_data *data, const struct cpumask *mask,
struct irq_chip *chip = irq_data_get_irq_chip(data); struct irq_chip *chip = irq_data_get_irq_chip(data);
int ret; int ret;
/* IRQs only run on the first CPU in the affinity mask; reflect that */
mask = cpumask_of(cpumask_first(mask));
ret = chip->irq_set_affinity(data, mask, force); ret = chip->irq_set_affinity(data, mask, force);
switch (ret) { switch (ret) {
case IRQ_SET_MASK_OK: case IRQ_SET_MASK_OK: