[PATCH v5 3/3] PCI: hv: Refactor hv_irq_unmask() to use cpumask_to_vpset()

[Maya Nakamura]

Remove the duplicate implementation of cpumask_to_vpset() and use the
shared implementation. Export hv_max_vp_index, which is required by
cpumask_to_vpset().

Signed-off-by: Maya Nakamura <m.maya.nakam...@gmail.com>
Reviewed-by: Michael Kelley <mikel...@microsoft.com>
Reviewed-by: Vitaly Kuznetsov <vkuzn...@redhat.com>
Tested-by: Vitaly Kuznetsov <vkuzn...@redhat.com>
---
Changes in v5:
 - Revise the commit message to clarify the changes based on feedback.
 - Add the Reviewed-by and Tested-by tags.

Changes in v4:
 - Replace GFP_KERNEL with GFP_ATOMIC for alloc_cpumask_var().
 - Update the commit message.

Changes in v3:
 - Modify to catch all failures from cpumask_to_vpset().
 - Correct the v2 change log about the commit message.

Changes in v2:
 - Remove unnecessary nr_bank initialization.
 - Delete two unnecessary dev_err()'s.
 - Unlock before returning.
 - Update the commit message.

 arch/x86/hyperv/hv_init.c           |  1 +
 drivers/pci/controller/pci-hyperv.c | 38 +++++++++++++----------------
 2 files changed, 18 insertions(+), 21 deletions(-)

diff --git a/arch/x86/hyperv/hv_init.c b/arch/x86/hyperv/hv_init.c
index 7abb09e2eeb8..7f2eed1fc81b 100644
--- a/arch/x86/hyperv/hv_init.c
+++ b/arch/x86/hyperv/hv_init.c
@@ -96,6 +96,7 @@ void  __percpu **hyperv_pcpu_input_arg;
 EXPORT_SYMBOL_GPL(hyperv_pcpu_input_arg);
 
 u32 hv_max_vp_index;
+EXPORT_SYMBOL_GPL(hv_max_vp_index);
 
 static int hv_cpu_init(unsigned int cpu)
 {
diff --git a/drivers/pci/controller/pci-hyperv.c 
b/drivers/pci/controller/pci-hyperv.c
index d71695db1ba0..95441a35eceb 100644
--- a/drivers/pci/controller/pci-hyperv.c
+++ b/drivers/pci/controller/pci-hyperv.c
@@ -391,8 +391,6 @@ struct hv_interrupt_entry {
        u32     data;
 };
 
-#define HV_VP_SET_BANK_COUNT_MAX       5 /* current implementation limit */
-
 /*
  * flags for hv_device_interrupt_target.flags
  */
@@ -908,12 +906,12 @@ static void hv_irq_unmask(struct irq_data *data)
        struct retarget_msi_interrupt *params;
        struct hv_pcibus_device *hbus;
        struct cpumask *dest;
+       cpumask_var_t tmp;
        struct pci_bus *pbus;
        struct pci_dev *pdev;
        unsigned long flags;
        u32 var_size = 0;
-       int cpu_vmbus;
-       int cpu;
+       int cpu, nr_bank;
        u64 res;
 
        dest = irq_data_get_effective_affinity_mask(data);
@@ -953,29 +951,27 @@ static void hv_irq_unmask(struct irq_data *data)
                 */
                params->int_target.flags |=
                        HV_DEVICE_INTERRUPT_TARGET_PROCESSOR_SET;
-               params->int_target.vp_set.valid_bank_mask =
-                       (1ull << HV_VP_SET_BANK_COUNT_MAX) - 1;
+
+               if (!alloc_cpumask_var(&tmp, GFP_ATOMIC)) {
+                       res = 1;
+                       goto exit_unlock;
+               }
+
+               cpumask_and(tmp, dest, cpu_online_mask);
+               nr_bank = cpumask_to_vpset(&params->int_target.vp_set, tmp);
+               free_cpumask_var(tmp);
+
+               if (nr_bank <= 0) {
+                       res = 1;
+                       goto exit_unlock;
+               }
 
                /*
                 * var-sized hypercall, var-size starts after vp_mask (thus
                 * vp_set.format does not count, but vp_set.valid_bank_mask
                 * does).
                 */
-               var_size = 1 + HV_VP_SET_BANK_COUNT_MAX;
-
-               for_each_cpu_and(cpu, dest, cpu_online_mask) {
-                       cpu_vmbus = hv_cpu_number_to_vp_number(cpu);
-
-                       if (cpu_vmbus >= HV_VP_SET_BANK_COUNT_MAX * 64) {
-                               dev_err(&hbus->hdev->device,
-                                       "too high CPU %d", cpu_vmbus);
-                               res = 1;
-                               goto exit_unlock;
-                       }
-
-                       params->int_target.vp_set.bank_contents[cpu_vmbus / 64] 
|=
-                               (1ULL << (cpu_vmbus & 63));
-               }
+               var_size = 1 + nr_bank;
        } else {
                for_each_cpu_and(cpu, dest, cpu_online_mask) {
                        params->int_target.vp_mask |=
-- 
2.17.1