[PATCH v3 7/8] genirq: Return a const cpumask from irq_data_get_affinity_mask

[Samuel Holland <samuel@xxxxxxxxxxxx>]

Now that the irq_data_update_affinity helper exists, enforce its use
by returning a a const cpumask from irq_data_get_affinity_mask.

Since the previous commit already updated places that needed to call
irq_data_update_affinity, this commit updates the remaining code that
either did not modify the cpumask or immediately passed the modified
mask to irq_set_affinity.

Signed-off-by: Samuel Holland <samuel@xxxxxxxxxxxx>
---

Changes in v3:
 - New patch to make the returned cpumasks const

 arch/mips/cavium-octeon/octeon-irq.c |  4 ++--
 arch/sh/kernel/irq.c                 |  7 ++++---
 arch/x86/hyperv/irqdomain.c          |  2 +-
 arch/xtensa/kernel/irq.c             |  7 ++++---
 drivers/iommu/hyperv-iommu.c         |  2 +-
 drivers/pci/controller/pci-hyperv.c  | 10 +++++-----
 include/linux/irq.h                  | 12 +++++++-----
 kernel/irq/chip.c                    |  8 +++++---
 kernel/irq/debugfs.c                 |  2 +-
 kernel/irq/ipi.c                     | 16 +++++++++-------
 10 files changed, 39 insertions(+), 31 deletions(-)

diff --git a/arch/mips/cavium-octeon/octeon-irq.c 
b/arch/mips/cavium-octeon/octeon-irq.c
index 6cdcbf4de763..9cb9ed44bcaf 100644
--- a/arch/mips/cavium-octeon/octeon-irq.c
+++ b/arch/mips/cavium-octeon/octeon-irq.c
@@ -263,7 +263,7 @@ static int next_cpu_for_irq(struct irq_data *data)
 
 #ifdef CONFIG_SMP
        int cpu;
-       struct cpumask *mask = irq_data_get_affinity_mask(data);
+       const struct cpumask *mask = irq_data_get_affinity_mask(data);
        int weight = cpumask_weight(mask);
        struct octeon_ciu_chip_data *cd = irq_data_get_irq_chip_data(data);
 
@@ -758,7 +758,7 @@ static void octeon_irq_cpu_offline_ciu(struct irq_data 
*data)
 {
        int cpu = smp_processor_id();
        cpumask_t new_affinity;
-       struct cpumask *mask = irq_data_get_affinity_mask(data);
+       const struct cpumask *mask = irq_data_get_affinity_mask(data);
 
        if (!cpumask_test_cpu(cpu, mask))
                return;
diff --git a/arch/sh/kernel/irq.c b/arch/sh/kernel/irq.c
index ef0f0827cf57..56269c2c3414 100644
--- a/arch/sh/kernel/irq.c
+++ b/arch/sh/kernel/irq.c
@@ -230,16 +230,17 @@ void migrate_irqs(void)
                struct irq_data *data = irq_get_irq_data(irq);
 
                if (irq_data_get_node(data) == cpu) {
-                       struct cpumask *mask = irq_data_get_affinity_mask(data);
+                       const struct cpumask *mask = 
irq_data_get_affinity_mask(data);
                        unsigned int newcpu = cpumask_any_and(mask,
                                                              cpu_online_mask);
                        if (newcpu >= nr_cpu_ids) {
                                pr_info_ratelimited("IRQ%u no longer affine to 
CPU%u\n",
                                                    irq, cpu);
 
-                               cpumask_setall(mask);
+                               irq_set_affinity(irq, cpu_all_mask);
+                       } else {
+                               irq_set_affinity(irq, mask);
                        }
-                       irq_set_affinity(irq, mask);
                }
        }
 }
diff --git a/arch/x86/hyperv/irqdomain.c b/arch/x86/hyperv/irqdomain.c
index 7e0f6bedc248..42c70d28ef27 100644
--- a/arch/x86/hyperv/irqdomain.c
+++ b/arch/x86/hyperv/irqdomain.c
@@ -192,7 +192,7 @@ static void hv_irq_compose_msi_msg(struct irq_data *data, 
struct msi_msg *msg)
        struct pci_dev *dev;
        struct hv_interrupt_entry out_entry, *stored_entry;
        struct irq_cfg *cfg = irqd_cfg(data);
-       cpumask_t *affinity;
+       const cpumask_t *affinity;
        int cpu;
        u64 status;
 
diff --git a/arch/xtensa/kernel/irq.c b/arch/xtensa/kernel/irq.c
index 529fe9245821..42f106004400 100644
--- a/arch/xtensa/kernel/irq.c
+++ b/arch/xtensa/kernel/irq.c
@@ -169,7 +169,7 @@ void migrate_irqs(void)
 
        for_each_active_irq(i) {
                struct irq_data *data = irq_get_irq_data(i);
-               struct cpumask *mask;
+               const struct cpumask *mask;
                unsigned int newcpu;
 
                if (irqd_is_per_cpu(data))
@@ -185,9 +185,10 @@ void migrate_irqs(void)
                        pr_info_ratelimited("IRQ%u no longer affine to CPU%u\n",
                                            i, cpu);
 
-                       cpumask_setall(mask);
+                       irq_set_affinity(i, cpu_all_mask);
+               } else {
+                       irq_set_affinity(i, mask);
                }
-               irq_set_affinity(i, mask);
        }
 }
 #endif /* CONFIG_HOTPLUG_CPU */
diff --git a/drivers/iommu/hyperv-iommu.c b/drivers/iommu/hyperv-iommu.c
index e285a220c913..51bd66a45a11 100644
--- a/drivers/iommu/hyperv-iommu.c
+++ b/drivers/iommu/hyperv-iommu.c
@@ -194,7 +194,7 @@ hyperv_root_ir_compose_msi_msg(struct irq_data *irq_data, 
struct msi_msg *msg)
        u32 vector;
        struct irq_cfg *cfg;
        int ioapic_id;
-       struct cpumask *affinity;
+       const struct cpumask *affinity;
        int cpu;
        struct hv_interrupt_entry entry;
        struct hyperv_root_ir_data *data = irq_data->chip_data;
diff --git a/drivers/pci/controller/pci-hyperv.c 
b/drivers/pci/controller/pci-hyperv.c
index db814f7b93ba..aebada45569b 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -642,7 +642,7 @@ static void hv_arch_irq_unmask(struct irq_data *data)
        struct hv_retarget_device_interrupt *params;
        struct tran_int_desc *int_desc;
        struct hv_pcibus_device *hbus;
-       struct cpumask *dest;
+       const struct cpumask *dest;
        cpumask_var_t tmp;
        struct pci_bus *pbus;
        struct pci_dev *pdev;
@@ -1613,7 +1613,7 @@ static void hv_pci_compose_compl(void *context, struct 
pci_response *resp,
 }
 
 static u32 hv_compose_msi_req_v1(
-       struct pci_create_interrupt *int_pkt, struct cpumask *affinity,
+       struct pci_create_interrupt *int_pkt, const struct cpumask *affinity,
        u32 slot, u8 vector, u8 vector_count)
 {
        int_pkt->message_type.type = PCI_CREATE_INTERRUPT_MESSAGE;
@@ -1641,7 +1641,7 @@ static int hv_compose_msi_req_get_cpu(struct cpumask 
*affinity)
 }
 
 static u32 hv_compose_msi_req_v2(
-       struct pci_create_interrupt2 *int_pkt, struct cpumask *affinity,
+       struct pci_create_interrupt2 *int_pkt, const struct cpumask *affinity,
        u32 slot, u8 vector, u8 vector_count)
 {
        int cpu;
@@ -1660,7 +1660,7 @@ static u32 hv_compose_msi_req_v2(
 }
 
 static u32 hv_compose_msi_req_v3(
-       struct pci_create_interrupt3 *int_pkt, struct cpumask *affinity,
+       struct pci_create_interrupt3 *int_pkt, const struct cpumask *affinity,
        u32 slot, u32 vector, u8 vector_count)
 {
        int cpu;
@@ -1697,7 +1697,7 @@ static void hv_compose_msi_msg(struct irq_data *data, 
struct msi_msg *msg)
        struct hv_pci_dev *hpdev;
        struct pci_bus *pbus;
        struct pci_dev *pdev;
-       struct cpumask *dest;
+       const struct cpumask *dest;
        struct compose_comp_ctxt comp;
        struct tran_int_desc *int_desc;
        struct msi_desc *msi_desc;
diff --git a/include/linux/irq.h b/include/linux/irq.h
index adcfebceb777..02073f7a156e 100644
--- a/include/linux/irq.h
+++ b/include/linux/irq.h
@@ -879,7 +879,8 @@ static inline int irq_data_get_node(struct irq_data *d)
        return irq_common_data_get_node(d->common);
 }
 
-static inline struct cpumask *irq_data_get_affinity_mask(struct irq_data *d)
+static inline
+const struct cpumask *irq_data_get_affinity_mask(struct irq_data *d)
 {
        return d->common->affinity;
 }
@@ -890,7 +891,7 @@ static inline void irq_data_update_affinity(struct irq_data 
*d,
        cpumask_copy(d->common->affinity, m);
 }
 
-static inline struct cpumask *irq_get_affinity_mask(int irq)
+static inline const struct cpumask *irq_get_affinity_mask(int irq)
 {
        struct irq_data *d = irq_get_irq_data(irq);
 
@@ -899,7 +900,7 @@ static inline struct cpumask *irq_get_affinity_mask(int irq)
 
 #ifdef CONFIG_GENERIC_IRQ_EFFECTIVE_AFF_MASK
 static inline
-struct cpumask *irq_data_get_effective_affinity_mask(struct irq_data *d)
+const struct cpumask *irq_data_get_effective_affinity_mask(struct irq_data *d)
 {
        return d->common->effective_affinity;
 }
@@ -914,13 +915,14 @@ static inline void 
irq_data_update_effective_affinity(struct irq_data *d,
 {
 }
 static inline
-struct cpumask *irq_data_get_effective_affinity_mask(struct irq_data *d)
+const struct cpumask *irq_data_get_effective_affinity_mask(struct irq_data *d)
 {
        return irq_data_get_affinity_mask(d);
 }
 #endif
 
-static inline struct cpumask *irq_get_effective_affinity_mask(unsigned int irq)
+static inline
+const struct cpumask *irq_get_effective_affinity_mask(unsigned int irq)
 {
        struct irq_data *d = irq_get_irq_data(irq);
 
diff --git a/kernel/irq/chip.c b/kernel/irq/chip.c
index 886789dcee43..9c7ad2266317 100644
--- a/kernel/irq/chip.c
+++ b/kernel/irq/chip.c
@@ -188,7 +188,8 @@ enum {
 
 #ifdef CONFIG_SMP
 static int
-__irq_startup_managed(struct irq_desc *desc, struct cpumask *aff, bool force)
+__irq_startup_managed(struct irq_desc *desc, const struct cpumask *aff,
+                     bool force)
 {
        struct irq_data *d = irq_desc_get_irq_data(desc);
 
@@ -224,7 +225,8 @@ __irq_startup_managed(struct irq_desc *desc, struct cpumask 
*aff, bool force)
 }
 #else
 static __always_inline int
-__irq_startup_managed(struct irq_desc *desc, struct cpumask *aff, bool force)
+__irq_startup_managed(struct irq_desc *desc, const struct cpumask *aff,
+                     bool force)
 {
        return IRQ_STARTUP_NORMAL;
 }
@@ -252,7 +254,7 @@ static int __irq_startup(struct irq_desc *desc)
 int irq_startup(struct irq_desc *desc, bool resend, bool force)
 {
        struct irq_data *d = irq_desc_get_irq_data(desc);
-       struct cpumask *aff = irq_data_get_affinity_mask(d);
+       const struct cpumask *aff = irq_data_get_affinity_mask(d);
        int ret = 0;
 
        desc->depth = 0;
diff --git a/kernel/irq/debugfs.c b/kernel/irq/debugfs.c
index bc8e40cf2b65..bbcaac64038e 100644
--- a/kernel/irq/debugfs.c
+++ b/kernel/irq/debugfs.c
@@ -30,7 +30,7 @@ static void irq_debug_show_bits(struct seq_file *m, int ind, 
unsigned int state,
 static void irq_debug_show_masks(struct seq_file *m, struct irq_desc *desc)
 {
        struct irq_data *data = irq_desc_get_irq_data(desc);
-       struct cpumask *msk;
+       const struct cpumask *msk;
 
        msk = irq_data_get_affinity_mask(data);
        seq_printf(m, "affinity: %*pbl\n", cpumask_pr_args(msk));
diff --git a/kernel/irq/ipi.c b/kernel/irq/ipi.c
index 08ce7da3b57c..bbd945bacef0 100644
--- a/kernel/irq/ipi.c
+++ b/kernel/irq/ipi.c
@@ -115,11 +115,11 @@ int irq_reserve_ipi(struct irq_domain *domain,
 int irq_destroy_ipi(unsigned int irq, const struct cpumask *dest)
 {
        struct irq_data *data = irq_get_irq_data(irq);
-       struct cpumask *ipimask = data ? irq_data_get_affinity_mask(data) : 
NULL;
+       const struct cpumask *ipimask;
        struct irq_domain *domain;
        unsigned int nr_irqs;
 
-       if (!irq || !data || !ipimask)
+       if (!irq || !data)
                return -EINVAL;
 
        domain = data->domain;
@@ -131,7 +131,8 @@ int irq_destroy_ipi(unsigned int irq, const struct cpumask 
*dest)
                return -EINVAL;
        }
 
-       if (WARN_ON(!cpumask_subset(dest, ipimask)))
+       ipimask = irq_data_get_affinity_mask(data);
+       if (!ipimask || WARN_ON(!cpumask_subset(dest, ipimask)))
                /*
                 * Must be destroying a subset of CPUs to which this IPI
                 * was set up to target
@@ -162,12 +163,13 @@ int irq_destroy_ipi(unsigned int irq, const struct 
cpumask *dest)
 irq_hw_number_t ipi_get_hwirq(unsigned int irq, unsigned int cpu)
 {
        struct irq_data *data = irq_get_irq_data(irq);
-       struct cpumask *ipimask = data ? irq_data_get_affinity_mask(data) : 
NULL;
+       const struct cpumask *ipimask;
 
-       if (!data || !ipimask || cpu >= nr_cpu_ids)
+       if (!data || cpu >= nr_cpu_ids)
                return INVALID_HWIRQ;
 
-       if (!cpumask_test_cpu(cpu, ipimask))
+       ipimask = irq_data_get_affinity_mask(data);
+       if (!ipimask || !cpumask_test_cpu(cpu, ipimask))
                return INVALID_HWIRQ;
 
        /*
@@ -186,7 +188,7 @@ EXPORT_SYMBOL_GPL(ipi_get_hwirq);
 static int ipi_send_verify(struct irq_chip *chip, struct irq_data *data,
                           const struct cpumask *dest, unsigned int cpu)
 {
-       struct cpumask *ipimask = irq_data_get_affinity_mask(data);
+       const struct cpumask *ipimask = irq_data_get_affinity_mask(data);
 
        if (!chip || !ipimask)
                return -EINVAL;
-- 
2.35.1