if (hbus->low_mmio_space && hbus->low_mmio_res) {
                hbus->low_mmio_res->flags |= IORESOURCE_BUSY;
-               release_mem_region(hbus->low_mmio_res->start,
-                                  resource_size(hbus->low_mmio_res));
+               vmbus_free_mmio(hbus->low_mmio_res->start,
+                               resource_size(hbus->low_mmio_res));
        }
 
        if (hbus->high_mmio_space && hbus->high_mmio_res) {
                hbus->high_mmio_res->flags |= IORESOURCE_BUSY;
-               release_mem_region(hbus->high_mmio_res->start,
-                                  resource_size(hbus->high_mmio_res));
+               vmbus_free_mmio(hbus->high_mmio_res->start,
+                               resource_size(hbus->high_mmio_res));
        }
 }
 
 
 release_low_mmio:
        if (hbus->low_mmio_res) {
-               release_mem_region(hbus->low_mmio_res->start,
-                                  resource_size(hbus->low_mmio_res));
+               vmbus_free_mmio(hbus->low_mmio_res->start,
+                               resource_size(hbus->low_mmio_res));
        }
 
        return ret;
 
 static void hv_free_config_window(struct hv_pcibus_device *hbus)
 {
-       release_mem_region(hbus->mem_config->start, PCI_CONFIG_MMIO_LENGTH);
+       vmbus_free_mmio(hbus->mem_config->start, PCI_CONFIG_MMIO_LENGTH);
 }
 
 /**
 
 err3:
        iounmap(fb_virt);
 err2:
-       release_mem_region(par->mem->start, screen_fb_size);
+       vmbus_free_mmio(par->mem->start, screen_fb_size);
        par->mem = NULL;
 err1:
        if (!gen2vm)
        struct hvfb_par *par = info->par;
 
        iounmap(info->screen_base);
-       release_mem_region(par->mem->start, screen_fb_size);
+       vmbus_free_mmio(par->mem->start, screen_fb_size);
        par->mem = NULL;
 }