On 07.07.22 11:39, Marc Zyngier wrote:


Hello Marc

On Sun, 03 Jul 2022 16:22:03 +0100,
Oleksandr [off-list ref] wrote:

quoted

On 01.07.22 23:00, Samuel Holland wrote:


Hello Samuel

quoted

Some architectures and irqchip drivers modify the cpumask returned by
irq_data_get_affinity_mask, usually by copying in to it. This is
problematic for uniprocessor configurations, where the affinity mask
should be constant, as it is known at compile time.

Add and use a setter for the affinity mask, following the pattern of
irq_data_update_effective_affinity. This allows the getter function to
return a const cpumask pointer.

Signed-off-by: Samuel Holland <samuel@sholland.org>
---

Changes in v3:
   - New patch to introduce irq_data_update_affinity

   arch/alpha/kernel/irq.c          | 2 +-
   arch/ia64/kernel/iosapic.c       | 2 +-
   arch/ia64/kernel/irq.c           | 4 ++--
   arch/ia64/kernel/msi_ia64.c      | 4 ++--
   arch/parisc/kernel/irq.c         | 2 +-
   drivers/irqchip/irq-bcm6345-l1.c | 4 ++--
   drivers/parisc/iosapic.c         | 2 +-
   drivers/sh/intc/chip.c           | 2 +-
   drivers/xen/events/events_base.c | 7 ++++---
   include/linux/irq.h              | 6 ++++++
   10 files changed, 21 insertions(+), 14 deletions(-)

diff --git a/arch/alpha/kernel/irq.c b/arch/alpha/kernel/irq.c
index f6d2946edbd2..15f2effd6baf 100644
--- a/arch/alpha/kernel/irq.c
+++ b/arch/alpha/kernel/irq.c

@@ -60,7 +60,7 @@ int irq_select_affinity(unsigned int irq)
   		cpu = (cpu < (NR_CPUS-1) ? cpu + 1 : 0);
   	last_cpu = cpu;
   -	cpumask_copy(irq_data_get_affinity_mask(data),

cpumask_of(cpu));
+	irq_data_update_affinity(data, cpumask_of(cpu));
   	chip->irq_set_affinity(data, cpumask_of(cpu), false);
   	return 0;
   }

diff --git a/arch/ia64/kernel/iosapic.c b/arch/ia64/kernel/iosapic.c
index 35adcf89035a..99300850abc1 100644
--- a/arch/ia64/kernel/iosapic.c
+++ b/arch/ia64/kernel/iosapic.c

@@ -834,7 +834,7 @@ iosapic_unregister_intr (unsigned int gsi)
   	if (iosapic_intr_info[irq].count == 0) {
   #ifdef CONFIG_SMP
   		/* Clear affinity */
-		cpumask_setall(irq_get_affinity_mask(irq));
+		irq_data_update_affinity(irq_get_irq_data(irq), cpu_all_mask);
   #endif
   		/* Clear the interrupt information */
   		iosapic_intr_info[irq].dest = 0;

diff --git a/arch/ia64/kernel/irq.c b/arch/ia64/kernel/irq.c
index ecef17c7c35b..275b9ea58c64 100644
--- a/arch/ia64/kernel/irq.c
+++ b/arch/ia64/kernel/irq.c

@@ -57,8 +57,8 @@ static char irq_redir [NR_IRQS]; // = { [0 ... NR_IRQS-1] = 1 };
   void set_irq_affinity_info (unsigned int irq, int hwid, int redir)
   {
   	if (irq < NR_IRQS) {
-		cpumask_copy(irq_get_affinity_mask(irq),
-			     cpumask_of(cpu_logical_id(hwid)));
+		irq_data_update_affinity(irq_get_irq_data(irq),
+					 cpumask_of(cpu_logical_id(hwid)));
   		irq_redir[irq] = (char) (redir & 0xff);
   	}
   }

diff --git a/arch/ia64/kernel/msi_ia64.c b/arch/ia64/kernel/msi_ia64.c
index df5c28f252e3..025e5133c860 100644
--- a/arch/ia64/kernel/msi_ia64.c
+++ b/arch/ia64/kernel/msi_ia64.c

@@ -37,7 +37,7 @@ static int ia64_set_msi_irq_affinity(struct irq_data *idata,
   	msg.data = data;
     	pci_write_msi_msg(irq, &msg);
-	cpumask_copy(irq_data_get_affinity_mask(idata), cpumask_of(cpu));
+	irq_data_update_affinity(idata, cpumask_of(cpu));
     	return 0;
   }

@@ -132,7 +132,7 @@ static int dmar_msi_set_affinity(struct irq_data *data,
   	msg.address_lo |= MSI_ADDR_DEST_ID_CPU(cpu_physical_id(cpu));
     	dmar_msi_write(irq, &msg);
-	cpumask_copy(irq_data_get_affinity_mask(data), mask);
+	irq_data_update_affinity(data, mask);
     	return 0;
   }

diff --git a/arch/parisc/kernel/irq.c b/arch/parisc/kernel/irq.c
index 0fe2d79fb123..5ebb1771b4ab 100644
--- a/arch/parisc/kernel/irq.c
+++ b/arch/parisc/kernel/irq.c

@@ -315,7 +315,7 @@ unsigned long txn_affinity_addr(unsigned int irq, int cpu)
   {
   #ifdef CONFIG_SMP
   	struct irq_data *d = irq_get_irq_data(irq);
-	cpumask_copy(irq_data_get_affinity_mask(d), cpumask_of(cpu));
+	irq_data_update_affinity(d, cpumask_of(cpu));
   #endif
     	return per_cpu(cpu_data, cpu).txn_addr;

diff --git a/drivers/irqchip/irq-bcm6345-l1.c b/drivers/irqchip/irq-bcm6345-l1.c
index 142a7431745f..6899e37810a8 100644
--- a/drivers/irqchip/irq-bcm6345-l1.c
+++ b/drivers/irqchip/irq-bcm6345-l1.c

@@ -216,11 +216,11 @@ static int bcm6345_l1_set_affinity(struct irq_data *d,
   		enabled = intc->cpus[old_cpu]->enable_cache[word] & mask;
   		if (enabled)
   			__bcm6345_l1_mask(d);
-		cpumask_copy(irq_data_get_affinity_mask(d), dest);
+		irq_data_update_affinity(d, dest);
   		if (enabled)
   			__bcm6345_l1_unmask(d);
   	} else {
-		cpumask_copy(irq_data_get_affinity_mask(d), dest);
+		irq_data_update_affinity(d, dest);
   	}
   	raw_spin_unlock_irqrestore(&intc->lock, flags);
   diff --git a/drivers/parisc/iosapic.c b/drivers/parisc/iosapic.c

index 8a3b0c3a1e92..3a8c98615634 100644
--- a/drivers/parisc/iosapic.c
+++ b/drivers/parisc/iosapic.c

@@ -677,7 +677,7 @@ static int iosapic_set_affinity_irq(struct irq_data *d,
   	if (dest_cpu < 0)
   		return -1;
   -	cpumask_copy(irq_data_get_affinity_mask(d),

cpumask_of(dest_cpu));
+	irq_data_update_affinity(d, cpumask_of(dest_cpu));
   	vi->txn_addr = txn_affinity_addr(d->irq, dest_cpu);
     	spin_lock_irqsave(&iosapic_lock, flags);

diff --git a/drivers/sh/intc/chip.c b/drivers/sh/intc/chip.c
index 358df7510186..828d81e02b37 100644
--- a/drivers/sh/intc/chip.c
+++ b/drivers/sh/intc/chip.c

@@ -72,7 +72,7 @@ static int intc_set_affinity(struct irq_data *data,
   	if (!cpumask_intersects(cpumask, cpu_online_mask))
   		return -1;
   -	cpumask_copy(irq_data_get_affinity_mask(data), cpumask);
+	irq_data_update_affinity(data, cpumask);
     	return IRQ_SET_MASK_OK_NOCOPY;
   }

diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index 46d9295d9a6e..5e8321f43cbd 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c

@@ -528,9 +528,10 @@ static void bind_evtchn_to_cpu(evtchn_port_t evtchn, unsigned int cpu,
   	BUG_ON(irq == -1);
     	if (IS_ENABLED(CONFIG_SMP) && force_affinity) {
-		cpumask_copy(irq_get_affinity_mask(irq), cpumask_of(cpu));
-		cpumask_copy(irq_get_effective_affinity_mask(irq),
-			     cpumask_of(cpu));
+		struct irq_data *data = irq_get_irq_data(irq);
+
+		irq_data_update_affinity(data, cpumask_of(cpu));
+		irq_data_update_effective_affinity(data, cpumask_of(cpu));
   	}

Nit: commit description says about reusing irq_data_update_affinity()
only, but here we also reuse irq_data_update_effective_affinity(), so
I would mention that in the description.

Reviewed-by: Oleksandr Tyshchenko <oleksandr_tyshchenko@epam.com> # Xen bits

b4 shouts because of your email address:

NOTE: some trailers ignored due to from/email mismatches:
     ! Trailer: Reviewed-by: Oleksandr Tyshchenko [off-list ref] # Xen bits
      Msg From: Oleksandr [off-list ref]

sorry for the inconvenience

I've used the tag anyway,

thank you

  but you may want to fix your setup in the
future.

yes, will do

Thanks,

	M.

-- 
Regards,

Oleksandr Tyshchenko