[PATCH] soc: ti: QMSS: Fix usage of irq_set_affinity_hint

Marc Zyngier
2018-10-30T11:11:03Z

The Keystone QMSS driver is pretty damaged, in the sense that it
does things like this:

irq_set_affinity_hint(irq, to_cpumask(&cpu_map));

where cpu_map is a local variable. As we leave the function, this
will point to nowhere-land, and things will end-up badly.

Instead, let's use a proper cpumask that gets allocated, giving
the driver a chance to actually work with things like irqbalance
as well as have a hypothetical 64bit future.

Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>
---
I found this one by inspection after finding a similar bug in an
unrelated driver. It is only compile-tested. It would probably
a Cc stable, but that's Santosh's decision.

drivers/soc/ti/knav_qmss.h | 4 ++--
drivers/soc/ti/knav_qmss_acc.c | 10 +++++-----
drivers/soc/ti/knav_qmss_queue.c | 22 +++++++++++++++-------
3 files changed, 22 insertions(+), 14 deletions(-)

diff --git a/drivers/soc/ti/knav_qmss.h b/drivers/soc/ti/knav_qmss.h
index 3efc47e82973..bd040c29c4bf 100644
--- a/drivers/soc/ti/knav_qmss.h
+++ b/drivers/soc/ti/knav_qmss.h
@@ -329,8 +329,8 @@ struct knav_range_ops {
};

struct knav_irq_info {
- int irq;
- u32 cpu_map;
+ int irq;
+ struct cpumask *cpu_mask;
};

struct knav_range_info {
diff --git a/drivers/soc/ti/knav_qmss_acc.c b/drivers/soc/ti/knav_qmss_acc.c
index 316e82e46f6c..2f7fb2dcc1d6 100644
--- a/drivers/soc/ti/knav_qmss_acc.c
+++ b/drivers/soc/ti/knav_qmss_acc.c
@@ -205,18 +205,18 @@ static int knav_range_setup_acc_irq(struct knav_range_info *range,
{
struct knav_device *kdev = range->kdev;
struct knav_acc_channel *acc;
- unsigned long cpu_map;
+ struct cpumask *cpu_mask;
int ret = 0, irq;
u32 old, new;

if (range->flags & RANGE_MULTI_QUEUE) {
acc = range->acc;
irq = range->irqs[0].irq;
- cpu_map = range->irqs[0].cpu_map;
+ cpu_mask = range->irqs[0].cpu_mask;
} else {
acc = range->acc + queue;
irq = range->irqs[queue].irq;
- cpu_map = range->irqs[queue].cpu_map;
+ cpu_mask = range->irqs[queue].cpu_mask;
}

old = acc->open_mask;
@@ -239,8 +239,8 @@ static int knav_range_setup_acc_irq(struct knav_range_info *range,
acc->name, acc->name);
ret = request_irq(irq, knav_acc_int_handler, 0, acc->name,
range);
- if (!ret && cpu_map) {
- ret = irq_set_affinity_hint(irq, to_cpumask(&cpu_map));
+ if (!ret && cpu_mask) {
+ ret = irq_set_affinity_hint(irq, cpu_mask);
if (ret) {
dev_warn(range->kdev->dev,
"Failed to set IRQ affinity\n");
diff --git a/drivers/soc/ti/knav_qmss_queue.c b/drivers/soc/ti/knav_qmss_queue.c
index b5d5673c255c..8b418379272d 100644
--- a/drivers/soc/ti/knav_qmss_queue.c
+++ b/drivers/soc/ti/knav_qmss_queue.c
@@ -118,19 +118,17 @@ static int knav_queue_setup_irq(struct knav_range_info *range,
struct knav_queue_inst *inst)
{
unsigned queue = inst->id - range->queue_base;
- unsigned long cpu_map;
int ret = 0, irq;

if (range->flags & RANGE_HAS_IRQ) {
irq = range->irqs[queue].irq;
- cpu_map = range->irqs[queue].cpu_map;
ret = request_irq(irq, knav_queue_int_handler, 0,
inst->irq_name, inst);
if (ret)
return ret;
disable_irq(irq);
- if (cpu_map) {
- ret = irq_set_affinity_hint(irq, to_cpumask(&cpu_map));
+ if (range->irqs[queue].cpu_mask) {
+ ret = irq_set_affinity_hint(irq, range->irqs[queue].cpu_mask);
if (ret) {
dev_warn(range->kdev->dev,
"Failed to set IRQ affinity\n");
@@ -1262,9 +1260,19 @@ static int knav_setup_queue_range(struct knav_device *kdev,

range->num_irqs++;

- if (IS_ENABLED(CONFIG_SMP) && oirq.args_count == 3)
- range->irqs[i].cpu_map =
- (oirq.args[2] & 0x0000ff00) >> 8;
+ if (IS_ENABLED(CONFIG_SMP) && oirq.args_count == 3) {
+ unsigned long mask;
+ int bit;
+
+ range->irqs[i].cpu_mask = devm_kzalloc(dev,
+ cpumask_size(), GFP_KERNEL);
+ if (!range->irqs[i].cpu_mask)
+ return -ENOMEM;
+
+ mask = (oirq.args[2] & 0x0000ff00) >> 8;
+ for_each_set_bit(bit, &mask, BITS_PER_LONG)
+ cpumask_set_cpu(bit, range->irqs[i].cpu_mask);
+ }
}

range->num_irqs = min(range->num_irqs, range->num_queues);
--
2.19.1