[PATCH v3 9/9] powerpc/xive: Modernize XIVE-IPI domain with an 'alloc' handler

[Cédric Le Goater]

Instead of calling irq_create_mapping() to map the IPI for a node,
introduce an 'alloc' handler. This is usually an extension to support
hierarchy irq_domains which is not exactly the case for XIVE-IPI
domain. However, we can now use the irq_domain_alloc_irqs() routine
which allocates the IRQ descriptor on the specified node, even better
for cache performance on multi node machines.

Cc: Thomas Gleixner <t...@linutronix.de>
Signed-off-by: Cédric Le Goater <c...@kaod.org>
---

 I didn't rerun the benchmark to check for a difference.
 
 arch/powerpc/sysdev/xive/common.c | 27 +++++++++++++++++++--------
 1 file changed, 19 insertions(+), 8 deletions(-)

diff --git a/arch/powerpc/sysdev/xive/common.c 
b/arch/powerpc/sysdev/xive/common.c
index 06f29cd07448..bb7435ffe99c 100644
--- a/arch/powerpc/sysdev/xive/common.c
+++ b/arch/powerpc/sysdev/xive/common.c
@@ -1103,15 +1103,26 @@ static struct irq_chip xive_ipi_chip = {
  * IPIs are marked per-cpu. We use separate HW interrupts under the
  * hood but associated with the same "linux" interrupt
  */
-static int xive_ipi_irq_domain_map(struct irq_domain *h, unsigned int virq,
-                                  irq_hw_number_t hw)
+struct xive_ipi_alloc_info {
+       irq_hw_number_t hwirq;
+};
+
+static int xive_ipi_irq_domain_alloc(struct irq_domain *domain, unsigned int 
virq,
+                                    unsigned int nr_irqs, void *arg)
 {
-       irq_set_chip_and_handler(virq, &xive_ipi_chip, handle_percpu_irq);
+       struct xive_ipi_alloc_info *info = arg;
+       int i;
+
+       for (i = 0; i < nr_irqs; i++) {
+               irq_domain_set_info(domain, virq + i, info->hwirq + i, 
&xive_ipi_chip,
+                                   domain->host_data, handle_percpu_irq,
+                                   NULL, NULL);
+       }
        return 0;
 }
 
 static const struct irq_domain_ops xive_ipi_irq_domain_ops = {
-       .map = xive_ipi_irq_domain_map,
+       .alloc  = xive_ipi_irq_domain_alloc,
 };
 
 static int __init xive_request_ipi(void)
@@ -1136,7 +1147,7 @@ static int __init xive_request_ipi(void)
 
        for_each_node(node) {
                struct xive_ipi_desc *xid = &xive_ipis[node];
-               irq_hw_number_t ipi_hwirq = node;
+               struct xive_ipi_alloc_info info = { node };
 
                /* Skip nodes without CPUs */
                if (cpumask_empty(cpumask_of_node(node)))
@@ -1147,9 +1158,9 @@ static int __init xive_request_ipi(void)
                 * Since the HW interrupt number doesn't have any meaning,
                 * simply use the node number.
                 */
-               xid->irq = irq_create_mapping(ipi_domain, ipi_hwirq);
-               if (!xid->irq) {
-                       ret = -EINVAL;
+               xid->irq = irq_domain_alloc_irqs(ipi_domain, 1, node, &info);
+               if (xid->irq < 0) {
+                       ret = xid->irq;
                        goto out_free_xive_ipis;
                }
 
-- 
2.26.3