KVM: cleanup io_device code

We modernize the io_device code so that we use container_of() instead of
dev->private, and move the vtable to a separate ops structure
(theoretically allows better caching for multiple instances of the same
ops structure)

Signed-off-by: Gregory Haskins <ghaskins@novell.com>
Acked-by: Chris Wright <chrisw@sous-sol.org>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 15 insertions, 10 deletions

diff --git a/virt/kvm/coalesced_mmio.c b/virt/kvm/coalesced_mmio.c
index 03ea2807b1f2..c4c7ec2f9d30 100644
--- a/virt/kvm/coalesced_mmio.c
+++ b/virt/kvm/coalesced_mmio.c
@@ -14,11 +14,15 @@
 
 #include "coalesced_mmio.h"
 
+static inline struct kvm_coalesced_mmio_dev *to_mmio(struct kvm_io_device *dev)
+{
+        return container_of(dev, struct kvm_coalesced_mmio_dev, dev);
+}
+
 static int coalesced_mmio_in_range(struct kvm_io_device *this,
                                    gpa_t addr, int len, int is_write)
 {
-        struct kvm_coalesced_mmio_dev *dev =
-                                (struct kvm_coalesced_mmio_dev*)this->private;
+        struct kvm_coalesced_mmio_dev *dev = to_mmio(this);
         struct kvm_coalesced_mmio_zone *zone;
         int next;
         int i;
@@ -63,8 +67,7 @@ static int coalesced_mmio_in_range(struct kvm_io_device *this,
 static void coalesced_mmio_write(struct kvm_io_device *this,
                                  gpa_t addr, int len, const void *val)
 {
-        struct kvm_coalesced_mmio_dev *dev =
-                                (struct kvm_coalesced_mmio_dev*)this->private;
+        struct kvm_coalesced_mmio_dev *dev = to_mmio(this);
         struct kvm_coalesced_mmio_ring *ring = dev->kvm->coalesced_mmio_ring;
 
         /* kvm->lock must be taken by caller before call to in_range()*/
@@ -80,12 +83,17 @@ static void coalesced_mmio_write(struct kvm_io_device *this,
 
 static void coalesced_mmio_destructor(struct kvm_io_device *this)
 {
-        struct kvm_coalesced_mmio_dev *dev =
-                (struct kvm_coalesced_mmio_dev *)this->private;
+        struct kvm_coalesced_mmio_dev *dev = to_mmio(this);
 
         kfree(dev);
 }
 
+static const struct kvm_io_device_ops coalesced_mmio_ops = {
+        .write      = coalesced_mmio_write,
+        .in_range   = coalesced_mmio_in_range,
+        .destructor = coalesced_mmio_destructor,
+};
+
 int kvm_coalesced_mmio_init(struct kvm *kvm)
 {
         struct kvm_coalesced_mmio_dev *dev;
@@ -93,10 +101,7 @@ int kvm_coalesced_mmio_init(struct kvm *kvm)
         dev = kzalloc(sizeof(struct kvm_coalesced_mmio_dev), GFP_KERNEL);
         if (!dev)
                 return -ENOMEM;
-        dev->dev.write  = coalesced_mmio_write;
-        dev->dev.in_range  = coalesced_mmio_in_range;
-        dev->dev.destructor  = coalesced_mmio_destructor;
-        dev->dev.private  = dev;
+        kvm_iodevice_init(&dev->dev, &coalesced_mmio_ops);
         dev->kvm = kvm;
         kvm->coalesced_mmio_dev = dev;
         kvm_io_bus_register_dev(&kvm->mmio_bus, &dev->dev);