x86/PCI: VMD: Eliminate index member from IRQ list

Use math to discover the IRQ list index number relative to the IRQ list
head.

Signed-off-by: Jon Derrick <jonathan.derrick@intel.com>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>
Acked-by: Keith Busch <keith.busch@intel.com>

1 files changed, 13 insertions, 7 deletions

diff --git a/arch/x86/pci/vmd.c b/arch/x86/pci/vmd.c
index 61a97ff36514..e785907acb79 100644
--- a/arch/x86/pci/vmd.c
+++ b/arch/x86/pci/vmd.c
@@ -56,13 +56,11 @@ struct vmd_irq {
 /**
  * struct vmd_irq_list - list of driver requested IRQs mapping to a VMD vector
  * @irq_list:   the list of irq's the VMD one demuxes to.
- * @index:      index into the VMD MSI-X table; used for message routing.
  * @count:      number of child IRQs assigned to this vector; used to track
  *              sharing.
  */
 struct vmd_irq_list {
         struct list_head        irq_list;
-        unsigned int            index;
         unsigned int            count;
 };
 
@@ -91,6 +89,12 @@ static inline struct vmd_dev *vmd_from_bus(struct pci_bus *bus)
         return container_of(bus->sysdata, struct vmd_dev, sysdata);
 }
 
+static inline unsigned int index_from_irqs(struct vmd_dev *vmd,
+                                           struct vmd_irq_list *irqs)
+{
+        return irqs - vmd->irqs;
+}
+
 /*
  * Drivers managing a device in a VMD domain allocate their own IRQs as before,
  * but the MSI entry for the hardware it's driving will be programmed with a
@@ -103,9 +107,11 @@ static void vmd_compose_msi_msg(struct irq_data *data, struct msi_msg *msg)
 {
         struct vmd_irq *vmdirq = data->chip_data;
         struct vmd_irq_list *irq = vmdirq->irq;
+        struct vmd_dev *vmd = irq_data_get_irq_handler_data(data);
 
         msg->address_hi = MSI_ADDR_BASE_HI;
-        msg->address_lo = MSI_ADDR_BASE_LO | MSI_ADDR_DEST_ID(irq->index);
+        msg->address_lo = MSI_ADDR_BASE_LO |
+                          MSI_ADDR_DEST_ID(index_from_irqs(vmd, irq));
         msg->data = 0;
 }
 
@@ -190,6 +196,7 @@ static int vmd_msi_init(struct irq_domain *domain, struct msi_domain_info *info,
         struct msi_desc *desc = arg->desc;
         struct vmd_dev *vmd = vmd_from_bus(msi_desc_to_pci_dev(desc)->bus);
         struct vmd_irq *vmdirq = kzalloc(sizeof(*vmdirq), GFP_KERNEL);
+        unsigned int index, vector;
 
         if (!vmdirq)
                 return -ENOMEM;
@@ -197,10 +204,10 @@ static int vmd_msi_init(struct irq_domain *domain, struct msi_domain_info *info,
         INIT_LIST_HEAD(&vmdirq->node);
         vmdirq->irq = vmd_next_irq(vmd, desc);
         vmdirq->virq = virq;
+        index = index_from_irqs(vmd, vmdirq->irq);
+        vector = pci_irq_vector(vmd->dev, index);
 
-        irq_domain_set_info(domain, virq,
-                            pci_irq_vector(vmd->dev, vmdirq->irq->index),
-                            info->chip, vmdirq,
+        irq_domain_set_info(domain, virq, vector, info->chip, vmdirq,
                             handle_untracked_irq, vmd, NULL);
         return 0;
 }
@@ -681,7 +688,6 @@ static int vmd_probe(struct pci_dev *dev, const struct pci_device_id *id)
 
         for (i = 0; i < vmd->msix_count; i++) {
                 INIT_LIST_HEAD(&vmd->irqs[i].irq_list);
-                vmd->irqs[i].index = i;
                 err = devm_request_irq(&dev->dev, pci_irq_vector(dev, i),
                                        vmd_irq, 0, "vmd", &vmd->irqs[i]);
                 if (err)