[PATCH v3 6/8] genirq: Add and use an irq_data_update_affinity helper

[Samuel Holland <samuel@xxxxxxxxxxxx>]

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@xxxxxxxxxxxx>
---

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));
        }
 
        xen_evtchn_port_bind_to_cpu(evtchn, cpu, info->cpu);
diff --git a/include/linux/irq.h b/include/linux/irq.h
index 69ee4e2f36ce..adcfebceb777 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -884,6 +884,12 @@ static inline struct cpumask 
*irq_data_get_affinity_mask(struct irq_data *d)
        return d->common->affinity;
 }
 
+static inline void irq_data_update_affinity(struct irq_data *d,
+                                           const struct cpumask *m)
+{
+       cpumask_copy(d->common->affinity, m);
+}
+
 static inline struct cpumask *irq_get_affinity_mask(int irq)
 {
        struct irq_data *d = irq_get_irq_data(irq);
-- 
2.35.1