genirq: Add irq_domain_set_affinity()

This allows a maximal affinity to be set, for IRQ domains which cannot
target all CPUs in the system.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>

diff --git a/include/linux/irqdomain.h b/include/linux/irqdomain.h
index 6b5576da77f0189c4050bbfa9cccafa8857938cc..cf686f18c1faa63c253257292a0110378064095e 100644 (file)
--- a/include/linux/irqdomain.h
+++ b/include/linux/irqdomain.h
@@ -151,6 +151,7 @@ struct irq_domain_chip_generic;
  *      drivers using the generic chip library which uses this pointer.
  * @parent: Pointer to parent irq_domain to support hierarchy irq_domains
  * @debugfs_file: dentry for the domain debugfs file
+ * @max_affinity: mask of CPUs targetable by this IRQ domain
  *
  * Revmap data, used internally by irq_domain
  * @revmap_direct_max_irq: The largest hwirq that can be set for controllers that
@@ -177,6 +178,7 @@ struct irq_domain {
 #ifdef CONFIG_GENERIC_IRQ_DEBUGFS
        struct dentry           *debugfs_file;
 #endif
+       const struct cpumask *max_affinity;
 
        /* reverse map data. The linear map gets appended to the irq_domain */
        irq_hw_number_t hwirq_max;
@@ -453,6 +455,8 @@ extern void irq_domain_set_info(struct irq_domain *domain, unsigned int virq,
                                void *chip_data, irq_flow_handler_t handler,
                                void *handler_data, const char *handler_name);
 extern void irq_domain_reset_irq_data(struct irq_data *irq_data);
+extern int irq_domain_set_affinity(struct irq_domain *domain,
+                                  const struct cpumask *affinity);
 #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
 extern struct irq_domain *irq_domain_create_hierarchy(struct irq_domain *parent,
                        unsigned int flags, unsigned int size,

diff --git a/kernel/irq/irqdomain.c b/kernel/irq/irqdomain.c
index ffd41f21afcacc634ffadb61b4f1f6b947224cdb..0b298355be1bc4dd6348118308f77ef661fb88c4 100644 (file)
--- a/kernel/irq/irqdomain.c
+++ b/kernel/irq/irqdomain.c
@@ -661,7 +661,7 @@ unsigned int irq_create_mapping(struct irq_domain *domain,
 
        /* Allocate a virtual interrupt number */
        virq = irq_domain_alloc_descs(-1, 1, hwirq, of_node_to_nid(of_node),
-                                     NULL, NULL);
+                                     NULL, domain->max_affinity);
        if (virq <= 0) {
                pr_debug("-> virq allocation failed\n");
                return 0;
@@ -1078,6 +1078,27 @@ void irq_domain_reset_irq_data(struct irq_data *irq_data)
 }
 EXPORT_SYMBOL_GPL(irq_domain_reset_irq_data);
 
+/**
+ * irq_domain_set_affinity - Set maximum CPU affinity for domain
+ * @parent:    Domain to set affinity for
+ * @affinity:  Pointer to cpumask, consumed by domain
+ *
+ * Sets the maximal set of CPUs to which interrupts in this domain may
+ * be delivered. Must only be called after creation, before any interrupts
+ * have been in the domain.
+ *
+ * This function retains a pointer to the cpumask which is passed in.
+ */
+int irq_domain_set_affinity(struct irq_domain *domain,
+                           const struct cpumask *affinity)
+{
+       if (cpumask_empty(affinity))
+               return -EINVAL;
+       domain->max_affinity = affinity;
+       return 0;
+}
+EXPORT_SYMBOL_GPL(irq_domain_set_affinity);
+
 #ifdef CONFIG_IRQ_DOMAIN_HIERARCHY
 /**
  * irq_domain_create_hierarchy - Add a irqdomain into the hierarchy
@@ -1110,6 +1131,9 @@ struct irq_domain *irq_domain_create_hierarchy(struct irq_domain *parent,
        if (domain) {
                domain->parent = parent;
                domain->flags |= flags;
+               if (parent && parent->max_affinity)
+                       irq_domain_set_affinity(domain,
+                                               parent->max_affinity);
        }
 
        return domain;
@@ -1375,7 +1399,7 @@ int __irq_domain_alloc_irqs(struct irq_domain *domain, int irq_base,
                virq = irq_base;
        } else {
                virq = irq_domain_alloc_descs(irq_base, nr_irqs, 0, node,
-                                             affinity, NULL);
+                                             affinity, domain->max_affinity);
                if (virq < 0) {
                        pr_debug("cannot allocate IRQ(base %d, count %d)\n",
                                 irq_base, nr_irqs);

diff --git a/kernel/irq/manage.c b/kernel/irq/manage.c
index 5df903fccb6094b93690cb909afc578743d972e7..e8c5f8ecd306b4fc4c068314fb4d60a25f376695 100644 (file)
--- a/kernel/irq/manage.c
+++ b/kernel/irq/manage.c
@@ -345,6 +345,10 @@ int irq_set_affinity_locked(struct irq_data *data, const struct cpumask *mask,
        struct irq_desc *desc = irq_data_to_desc(data);
        int ret = 0;
 
+       if (data->domain && data->domain->max_affinity &&
+           !cpumask_subset(mask, data->domain->max_affinity))
+               return -EINVAL;
+
        if (!chip || !chip->irq_set_affinity)
                return -EINVAL;
 
@@ -484,13 +488,20 @@ int irq_setup_affinity(struct irq_desc *desc)
        struct cpumask *set = irq_default_affinity;
        int ret, node = irq_desc_get_node(desc);
        static DEFINE_RAW_SPINLOCK(mask_lock);
-       static struct cpumask mask;
+       static struct cpumask mask, max_mask;
 
        /* Excludes PER_CPU and NO_BALANCE interrupts */
        if (!__irq_can_set_affinity(desc))
                return 0;
 
        raw_spin_lock(&mask_lock);
+
+       if (desc->irq_data.domain && desc->irq_data.domain->max_affinity)
+               cpumask_and(&max_mask, cpu_online_mask,
+                           desc->irq_data.domain->max_affinity);
+       else
+               cpumask_copy(&max_mask, cpu_online_mask);
+
        /*
         * Preserve the managed affinity setting and a userspace affinity
         * setup, but make sure that one of the targets is online.
@@ -498,15 +509,15 @@ int irq_setup_affinity(struct irq_desc *desc)
        if (irqd_affinity_is_managed(&desc->irq_data) ||
            irqd_has_set(&desc->irq_data, IRQD_AFFINITY_SET)) {
                if (cpumask_intersects(desc->irq_common_data.affinity,
-                                      cpu_online_mask))
+                                      &max_mask))
                        set = desc->irq_common_data.affinity;
                else
                        irqd_clear(&desc->irq_data, IRQD_AFFINITY_SET);
        }
 
-       cpumask_and(&mask, cpu_online_mask, set);
+       cpumask_and(&mask, &max_mask, set);
        if (cpumask_empty(&mask))
-               cpumask_copy(&mask, cpu_online_mask);
+               cpumask_copy(&mask, &max_mask);
 
        if (node != NUMA_NO_NODE) {
                const struct cpumask *nodemask = cpumask_of_node(node);