Drivers: hv: vmbus: use cpu_hotplug_enable/disable

Commit e513229b4c38 ("Drivers: hv: vmbus: prevent cpu offlining on newer
hypervisors") was altering smp_ops.cpu_disable to prevent CPU offlining.
We can bo better by using cpu_hotplug_enable/disable functions instead of
such hard-coding.

Reported-by: Radim Kr.má  <rkrcmar@redhat.com>
Signed-off-by: Vitaly Kuznetsov <vkuznets@redhat.com>
Signed-off-by: K. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/hv/vmbus_drv.c b/drivers/hv/vmbus_drv.c
index 45d6d7a..f19b6f7 100644 (file)
--- a/drivers/hv/vmbus_drv.c
+++ b/drivers/hv/vmbus_drv.c
@@ -828,38 +828,6 @@ static void vmbus_isr(void)
        }
 }
 
-#ifdef CONFIG_HOTPLUG_CPU
-static int hyperv_cpu_disable(void)
-{
-       return -ENOSYS;
-}
-
-static void hv_cpu_hotplug_quirk(bool vmbus_loaded)
-{
-       static void *previous_cpu_disable;
-
-       /*
-        * Offlining a CPU when running on newer hypervisors (WS2012R2, Win8,
-        * ...) is not supported at this moment as channel interrupts are
-        * distributed across all of them.
-        */
-
-       if ((vmbus_proto_version == VERSION_WS2008) ||
-           (vmbus_proto_version == VERSION_WIN7))
-               return;
-
-       if (vmbus_loaded) {
-               previous_cpu_disable = smp_ops.cpu_disable;
-               smp_ops.cpu_disable = hyperv_cpu_disable;
-               pr_notice("CPU offlining is not supported by hypervisor\n");
-       } else if (previous_cpu_disable)
-               smp_ops.cpu_disable = previous_cpu_disable;
-}
-#else
-static void hv_cpu_hotplug_quirk(bool vmbus_loaded)
-{
-}
-#endif
 
 /*
  * vmbus_bus_init -Main vmbus driver initialization routine.
@@ -901,7 +869,8 @@ static int vmbus_bus_init(int irq)
        if (ret)
                goto err_alloc;
 
-       hv_cpu_hotplug_quirk(true);
+       if (vmbus_proto_version > VERSION_WIN7)
+               cpu_hotplug_disable();
 
        /*
         * Only register if the crash MSRs are available
@@ -1364,7 +1333,8 @@ static void __exit vmbus_exit(void)
        }
        hv_synic_free();
        acpi_bus_unregister_driver(&vmbus_acpi_driver);
-       hv_cpu_hotplug_quirk(false);
+       if (vmbus_proto_version > VERSION_WIN7)
+               cpu_hotplug_enable();
 }