drivers/xen/gntdev: use xen_pv_domain() instead of cached value

Eliminate the use_ptemod variable by replacing its use cases with
xen_pv_domain().

Instead of passing the xen_pv_domain() return value to
gntdev_ioctl_dmabuf_exp_from_refs(), use xen_pv_domain() in that
function.

Reviewed-by: Jason Andryuk <[e-mail]>
Signed-off-by: Juergen Gross <[e-mail]>
Message-ID: <[e-mail]>

drivers/xen/gntdev-dmabuf.c

···
 
 /* DMA buffer IOCTL support. */
 
-long gntdev_ioctl_dmabuf_exp_from_refs(struct gntdev_priv *priv, int use_ptemod,
+long gntdev_ioctl_dmabuf_exp_from_refs(struct gntdev_priv *priv,
 				       struct ioctl_gntdev_dmabuf_exp_from_refs __user *u)
 {
 	struct ioctl_gntdev_dmabuf_exp_from_refs op;
 	u32 *refs;
 	long ret;
 
-	if (use_ptemod) {
-		pr_debug("Cannot provide dma-buf: use_ptemode %d\n",
-			 use_ptemod);
+	if (xen_pv_domain()) {
+		pr_debug("Cannot provide dma-buf in a PV domain\n");
 		return -EINVAL;
 	}
 

drivers/xen/gntdev-dmabuf.h

···
 
 void gntdev_dmabuf_fini(struct gntdev_dmabuf_priv *priv);
 
-long gntdev_ioctl_dmabuf_exp_from_refs(struct gntdev_priv *priv, int use_ptemod,
+long gntdev_ioctl_dmabuf_exp_from_refs(struct gntdev_priv *priv,
 				       struct ioctl_gntdev_dmabuf_exp_from_refs __user *u);
 
 long gntdev_ioctl_dmabuf_exp_wait_released(struct gntdev_priv *priv,

drivers/xen/gntdev.c

···
 MODULE_PARM_DESC(limit,
 	"Maximum number of grants that may be mapped by one mapping request");
 
-/* True in PV mode, false otherwise */
-static int use_ptemod;
-
 static void unmap_grant_pages(struct gntdev_grant_map *map,
 			      int offset, int pages);
 
···
 	    NULL == add->pages     ||
 	    NULL == add->being_removed)
 		goto err;
-	if (use_ptemod) {
+	if (xen_pv_domain()) {
 		add->kmap_ops   = kvmalloc_array(count, sizeof(add->kmap_ops[0]),
 						 GFP_KERNEL);
 		add->kunmap_ops = kvmalloc_array(count, sizeof(add->kunmap_ops[0]),
···
 		add->grants[i].ref = INVALID_GRANT_REF;
 		add->map_ops[i].handle = INVALID_GRANT_HANDLE;
 		add->unmap_ops[i].handle = INVALID_GRANT_HANDLE;
-		if (use_ptemod) {
+		if (xen_pv_domain()) {
 			add->kmap_ops[i].handle = INVALID_GRANT_HANDLE;
 			add->kunmap_ops[i].handle = INVALID_GRANT_HANDLE;
 		}
···
 	if (!refcount_dec_and_test(&map->users))
 		return;
 
-	if (map->pages && !use_ptemod) {
+	if (map->pages && !xen_pv_domain()) {
 		/*
 		 * Increment the reference count.  This ensures that the
 		 * subsequent call to unmap_grant_pages() will not wind up
···
 		 */
 	}
 
-	if (use_ptemod && map->notifier_init)
+	if (xen_pv_domain() && map->notifier_init)
 		mmu_interval_notifier_remove(&map->notifier);
 
 	if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) {
···
 	size_t alloced = 0;
 	int i, err = 0;
 
-	if (!use_ptemod) {
+	if (!xen_pv_domain()) {
 		/* Note: it could already be mapped */
 		if (map->map_ops[0].handle != INVALID_GRANT_HANDLE)
 			return 0;
···
 		if (map->flags & GNTMAP_device_map)
 			map->unmap_ops[i].dev_bus_addr = map->map_ops[i].dev_bus_addr;
 
-		if (use_ptemod) {
+		if (xen_pv_domain()) {
 			if (map->kmap_ops[i].status == GNTST_okay) {
 				alloced++;
 				map->kunmap_ops[i].handle = map->kmap_ops[i].handle;
···
 			map->unmap_ops[offset+i].handle,
 			map->unmap_ops[offset+i].status);
 		map->unmap_ops[offset+i].handle = INVALID_GRANT_HANDLE;
-		if (use_ptemod) {
+		if (xen_pv_domain()) {
 			if (map->kunmap_ops[offset + i].status == GNTST_okay &&
 			    map->kunmap_ops[offset + i].handle != INVALID_GRANT_HANDLE)
 				successful_unmaps++;
···
 	}
 
 	map->unmap_data.unmap_ops = map->unmap_ops + offset;
-	map->unmap_data.kunmap_ops = use_ptemod ? map->kunmap_ops + offset : NULL;
+	map->unmap_data.kunmap_ops = xen_pv_domain() ? map->kunmap_ops + offset : NULL;
 	map->unmap_data.pages = map->pages + offset;
 	map->unmap_data.count = pages;
 	map->unmap_data.done = __unmap_grant_pages_done;
···
 
 #ifdef CONFIG_XEN_GNTDEV_DMABUF
 	case IOCTL_GNTDEV_DMABUF_EXP_FROM_REFS:
-		return gntdev_ioctl_dmabuf_exp_from_refs(priv, use_ptemod, ptr);
+		return gntdev_ioctl_dmabuf_exp_from_refs(priv, ptr);
 
 	case IOCTL_GNTDEV_DMABUF_EXP_WAIT_RELEASED:
 		return gntdev_ioctl_dmabuf_exp_wait_released(priv, ptr);
···
 
 	vm_flags_set(vma, VM_DONTEXPAND | VM_DONTDUMP | VM_MIXEDMAP);
 
-	if (use_ptemod)
+	if (xen_pv_domain())
 		vm_flags_set(vma, VM_DONTCOPY);
 
 	vma->vm_private_data = map;
···
 
 	map->pages_vm_start = vma->vm_start;
 
-	if (use_ptemod) {
+	if (xen_pv_domain()) {
 		err = mmu_interval_notifier_insert_locked(
 			&map->notifier, vma->vm_mm, vma->vm_start,
 			vma->vm_end - vma->vm_start, &gntdev_mmu_ops);
···
 	}
 	mutex_unlock(&priv->lock);
 
-	if (use_ptemod) {
+	if (xen_pv_domain()) {
 		/*
 		 * gntdev takes the address of the PTE in find_grant_ptes() and
 		 * passes it to the hypervisor in gntdev_map_grant_pages(). The
···
 	if (err)
 		goto out_put_map;
 
-	if (!use_ptemod) {
+	if (!xen_pv_domain()) {
 		err = vm_map_pages_zero(vma, map->pages, map->count);
 		if (err)
 			goto out_put_map;
···
 out_unlock_put:
 	mutex_unlock(&priv->lock);
 out_put_map:
-	if (use_ptemod)
+	if (xen_pv_domain())
 		unmap_grant_pages(map, 0, map->count);
 	gntdev_put_map(priv, map);
 	return err;
···
 
 	if (!xen_domain())
 		return -ENODEV;
-
-	use_ptemod = xen_pv_domain();
 
 	err = misc_register(&gntdev_miscdev);
 	if (err != 0) {