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

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Hi Greg,

On 10/30/2018 4:11 AM, Marc Zyngier wrote:
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@xxxxxxx>
---
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.

Would be able to apply this fix from Marc for stable or it needs
to be re-posted with CC to stable ?


  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);




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