1 files changed, 203 insertions, 117 deletions

diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index 59ffea800079..2c960f187f7c 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -35,6 +35,7 @@
 #include <linux/slab.h>
 #include <linux/highmem.h>
 #include <linux/refcount.h>
+#include <linux/workqueue.h>
 
 #include <xen/xen.h>
 #include <xen/grant_table.h>
@@ -55,15 +56,25 @@ MODULE_AUTHOR("Derek G. Murray <Derek.Murray@cl.cam.ac.uk>, "
 	      "Gerd Hoffmann <kraxel@redhat.com>");
 MODULE_DESCRIPTION("User-space granted page access driver");
 
+#define GNTDEV_COPY_BATCH 16
+
+struct gntdev_copy_batch {
+	struct gnttab_copy ops[GNTDEV_COPY_BATCH];
+	struct page *pages[GNTDEV_COPY_BATCH];
+	s16 __user *status[GNTDEV_COPY_BATCH];
+	unsigned int nr_ops;
+	unsigned int nr_pages;
+	bool writeable;
+	struct gntdev_copy_batch *next;
+};
+
 static unsigned int limit = 64*1024;
 module_param(limit, uint, 0644);
 MODULE_PARM_DESC(limit,
 	"Maximum number of grants that may be mapped by one mapping request");
 
-static int use_ptemod;
-
-static int unmap_grant_pages(struct gntdev_grant_map *map,
-			     int offset, int pages);
+static void unmap_grant_pages(struct gntdev_grant_map *map,
+			      int offset, int pages);
 
 static struct miscdevice gntdev_miscdev;
 
@@ -120,6 +131,7 @@ static void gntdev_free_map(struct gntdev_grant_map *map)
 	kvfree(map->unmap_ops);
 	kvfree(map->kmap_ops);
 	kvfree(map->kunmap_ops);
+	kvfree(map->being_removed);
 	kfree(map);
 }
 
@@ -140,12 +152,15 @@ struct gntdev_grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count,
 	add->unmap_ops = kvmalloc_array(count, sizeof(add->unmap_ops[0]),
 					GFP_KERNEL);
 	add->pages     = kvcalloc(count, sizeof(add->pages[0]), GFP_KERNEL);
+	add->being_removed =
+		kvcalloc(count, sizeof(add->being_removed[0]), GFP_KERNEL);
 	if (NULL == add->grants    ||
 	    NULL == add->map_ops   ||
 	    NULL == add->unmap_ops ||
-	    NULL == add->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]),
@@ -193,7 +208,7 @@ struct gntdev_grant_map *gntdev_alloc_map(struct gntdev_priv *priv, int count,
 		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;
 		}
@@ -250,9 +265,39 @@ void gntdev_put_map(struct gntdev_priv *priv, struct gntdev_grant_map *map)
 	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
+		 * re-entering itself.  It *can* wind up calling
+		 * gntdev_put_map() recursively, but such calls will be with a
+		 * reference count greater than 1, so they will return before
+		 * this code is reached.  The recursion depth is thus limited to
+		 * 1.  Do NOT use refcount_inc() here, as it will detect that
+		 * the reference count is zero and WARN().
+		 */
+		refcount_set(&map->users, 1);
+
+		/*
+		 * Unmap the grants.  This may or may not be asynchronous, so it
+		 * is possible that the reference count is 1 on return, but it
+		 * could also be greater than 1.
+		 */
 		unmap_grant_pages(map, 0, map->count);
 
+		/* Check if the memory now needs to be freed */
+		if (!refcount_dec_and_test(&map->users))
+			return;
+
+		/*
+		 * All pages have been returned to the hypervisor, so free the
+		 * map.
+		 */
+	}
+
+	if (xen_pv_domain() && map->notifier_init)
+		mmu_interval_notifier_remove(&map->notifier);
+
 	if (map->notify.flags & UNMAP_NOTIFY_SEND_EVENT) {
 		notify_remote_via_evtchn(map->notify.event);
 		evtchn_put(map->notify.event);
@@ -265,7 +310,7 @@ void gntdev_put_map(struct gntdev_priv *priv, struct gntdev_grant_map *map)
 static int find_grant_ptes(pte_t *pte, unsigned long addr, void *data)
 {
 	struct gntdev_grant_map *map = data;
-	unsigned int pgnr = (addr - map->vma->vm_start) >> PAGE_SHIFT;
+	unsigned int pgnr = (addr - map->pages_vm_start) >> PAGE_SHIFT;
 	int flags = map->flags | GNTMAP_application_map | GNTMAP_contains_pte |
 		    (1 << _GNTMAP_guest_avail0);
 	u64 pte_maddr;
@@ -273,6 +318,7 @@ static int find_grant_ptes(pte_t *pte, unsigned long addr, void *data)
 	BUG_ON(pgnr >= map->count);
 	pte_maddr = arbitrary_virt_to_machine(pte).maddr;
 
+	/* Note: this will perform a pte_mkspecial() through the hypercall. */
 	gnttab_set_map_op(&map->map_ops[pgnr], pte_maddr, flags,
 			  map->grants[pgnr].ref,
 			  map->grants[pgnr].domid);
@@ -283,9 +329,10 @@ static int find_grant_ptes(pte_t *pte, unsigned long addr, void *data)
 
 int gntdev_map_grant_pages(struct gntdev_grant_map *map)
 {
+	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;
@@ -331,97 +378,130 @@ int gntdev_map_grant_pages(struct gntdev_grant_map *map)
 			map->count);
 
 	for (i = 0; i < map->count; i++) {
-		if (map->map_ops[i].status == GNTST_okay)
+		if (map->map_ops[i].status == GNTST_okay) {
 			map->unmap_ops[i].handle = map->map_ops[i].handle;
-		else if (!err)
+			alloced++;
+		} else if (!err)
 			err = -EINVAL;
 
 		if (map->flags & GNTMAP_device_map)
 			map->unmap_ops[i].dev_bus_addr = map->map_ops[i].dev_bus_addr;
 
-		if (use_ptemod) {
-			if (map->kmap_ops[i].status == GNTST_okay)
+		if (xen_pv_domain()) {
+			if (map->kmap_ops[i].status == GNTST_okay) {
+				alloced++;
 				map->kunmap_ops[i].handle = map->kmap_ops[i].handle;
-			else if (!err)
+			} else if (!err)
 				err = -EINVAL;
 		}
 	}
+	atomic_add(alloced, &map->live_grants);
 	return err;
 }
 
-static int __unmap_grant_pages(struct gntdev_grant_map *map, int offset,
-			       int pages)
+static void __unmap_grant_pages_done(int result,
+		struct gntab_unmap_queue_data *data)
 {
-	int i, err = 0;
-	struct gntab_unmap_queue_data unmap_data;
+	unsigned int i;
+	struct gntdev_grant_map *map = data->data;
+	unsigned int offset = data->unmap_ops - map->unmap_ops;
+	int successful_unmaps = 0;
+	int live_grants;
+
+	for (i = 0; i < data->count; i++) {
+		if (map->unmap_ops[offset + i].status == GNTST_okay &&
+		    map->unmap_ops[offset + i].handle != INVALID_GRANT_HANDLE)
+			successful_unmaps++;
+
+		WARN_ON(map->unmap_ops[offset + i].status != GNTST_okay &&
+			map->unmap_ops[offset + i].handle != INVALID_GRANT_HANDLE);
+		pr_debug("unmap handle=%d st=%d\n",
+			map->unmap_ops[offset+i].handle,
+			map->unmap_ops[offset+i].status);
+		map->unmap_ops[offset+i].handle = INVALID_GRANT_HANDLE;
+		if (xen_pv_domain()) {
+			if (map->kunmap_ops[offset + i].status == GNTST_okay &&
+			    map->kunmap_ops[offset + i].handle != INVALID_GRANT_HANDLE)
+				successful_unmaps++;
+
+			WARN_ON(map->kunmap_ops[offset + i].status != GNTST_okay &&
+				map->kunmap_ops[offset + i].handle != INVALID_GRANT_HANDLE);
+			pr_debug("kunmap handle=%u st=%d\n",
+				 map->kunmap_ops[offset+i].handle,
+				 map->kunmap_ops[offset+i].status);
+			map->kunmap_ops[offset+i].handle = INVALID_GRANT_HANDLE;
+		}
+	}
+
+	/*
+	 * Decrease the live-grant counter.  This must happen after the loop to
+	 * prevent premature reuse of the grants by gnttab_mmap().
+	 */
+	live_grants = atomic_sub_return(successful_unmaps, &map->live_grants);
+	if (WARN_ON(live_grants < 0))
+		pr_err("%s: live_grants became negative (%d) after unmapping %d pages!\n",
+		       __func__, live_grants, successful_unmaps);
+
+	/* Release reference taken by __unmap_grant_pages */
+	gntdev_put_map(NULL, map);
+}
 
+static void __unmap_grant_pages(struct gntdev_grant_map *map, int offset,
+			       int pages)
+{
 	if (map->notify.flags & UNMAP_NOTIFY_CLEAR_BYTE) {
 		int pgno = (map->notify.addr >> PAGE_SHIFT);
+
 		if (pgno >= offset && pgno < offset + pages) {
 			/* No need for kmap, pages are in lowmem */
 			uint8_t *tmp = pfn_to_kaddr(page_to_pfn(map->pages[pgno]));
+
 			tmp[map->notify.addr & (PAGE_SIZE-1)] = 0;
 			map->notify.flags &= ~UNMAP_NOTIFY_CLEAR_BYTE;
 		}
 	}
 
-	unmap_data.unmap_ops = map->unmap_ops + offset;
-	unmap_data.kunmap_ops = use_ptemod ? map->kunmap_ops + offset : NULL;
-	unmap_data.pages = map->pages + offset;
-	unmap_data.count = pages;
-
-	err = gnttab_unmap_refs_sync(&unmap_data);
-	if (err)
-		return err;
+	map->unmap_data.unmap_ops = map->unmap_ops + offset;
+	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;
+	map->unmap_data.data = map;
+	refcount_inc(&map->users); /* to keep map alive during async call below */
 
-	for (i = 0; i < pages; i++) {
-		if (map->unmap_ops[offset+i].status)
-			err = -EINVAL;
-		pr_debug("unmap handle=%d st=%d\n",
-			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 (map->kunmap_ops[offset+i].status)
-				err = -EINVAL;
-			pr_debug("kunmap handle=%u st=%d\n",
-				 map->kunmap_ops[offset+i].handle,
-				 map->kunmap_ops[offset+i].status);
-			map->kunmap_ops[offset+i].handle = INVALID_GRANT_HANDLE;
-		}
-	}
-	return err;
+	gnttab_unmap_refs_async(&map->unmap_data);
 }
 
-static int unmap_grant_pages(struct gntdev_grant_map *map, int offset,
-			     int pages)
+static void unmap_grant_pages(struct gntdev_grant_map *map, int offset,
+			      int pages)
 {
-	int range, err = 0;
+	int range;
+
+	if (atomic_read(&map->live_grants) == 0)
+		return; /* Nothing to do */
 
 	pr_debug("unmap %d+%d [%d+%d]\n", map->index, map->count, offset, pages);
 
 	/* It is possible the requested range will have a "hole" where we
 	 * already unmapped some of the grants. Only unmap valid ranges.
 	 */
-	while (pages && !err) {
-		while (pages &&
-		       map->unmap_ops[offset].handle == INVALID_GRANT_HANDLE) {
+	while (pages) {
+		while (pages && map->being_removed[offset]) {
 			offset++;
 			pages--;
 		}
 		range = 0;
 		while (range < pages) {
-			if (map->unmap_ops[offset + range].handle ==
-			    INVALID_GRANT_HANDLE)
+			if (map->being_removed[offset + range])
 				break;
+			map->being_removed[offset + range] = true;
 			range++;
 		}
-		err = __unmap_grant_pages(map, offset, range);
+		if (range)
+			__unmap_grant_pages(map, offset, range);
 		offset += range;
 		pages -= range;
 	}
-
-	return err;
 }
 
 /* ------------------------------------------------------------------ */
@@ -441,16 +521,12 @@ static void gntdev_vma_close(struct vm_area_struct *vma)
 	struct gntdev_priv *priv = file->private_data;
 
 	pr_debug("gntdev_vma_close %p\n", vma);
-	if (use_ptemod) {
-		WARN_ON(map->vma != vma);
-		mmu_interval_notifier_remove(&map->notifier);
-		map->vma = NULL;
-	}
+
 	vma->vm_private_data = NULL;
 	gntdev_put_map(priv, map);
 }
 
-static struct page *gntdev_vma_find_special_page(struct vm_area_struct *vma,
+static struct page *gntdev_vma_find_normal_page(struct vm_area_struct *vma,
 						 unsigned long addr)
 {
 	struct gntdev_grant_map *map = vma->vm_private_data;
@@ -461,7 +537,7 @@ static struct page *gntdev_vma_find_special_page(struct vm_area_struct *vma,
 static const struct vm_operations_struct gntdev_vmops = {
 	.open = gntdev_vma_open,
 	.close = gntdev_vma_close,
-	.find_special_page = gntdev_vma_find_special_page,
+	.find_normal_page = gntdev_vma_find_normal_page,
 };
 
 /* ------------------------------------------------------------------ */
@@ -473,31 +549,30 @@ static bool gntdev_invalidate(struct mmu_interval_notifier *mn,
 	struct gntdev_grant_map *map =
 		container_of(mn, struct gntdev_grant_map, notifier);
 	unsigned long mstart, mend;
-	int err;
+	unsigned long map_start, map_end;
 
 	if (!mmu_notifier_range_blockable(range))
 		return false;
 
+	map_start = map->pages_vm_start;
+	map_end = map->pages_vm_start + (map->count << PAGE_SHIFT);
+
 	/*
 	 * If the VMA is split or otherwise changed the notifier is not
 	 * updated, but we don't want to process VA's outside the modified
 	 * VMA. FIXME: It would be much more understandable to just prevent
 	 * modifying the VMA in the first place.
 	 */
-	if (map->vma->vm_start >= range->end ||
-	    map->vma->vm_end <= range->start)
+	if (map_start >= range->end || map_end <= range->start)
 		return true;
 
-	mstart = max(range->start, map->vma->vm_start);
-	mend = min(range->end, map->vma->vm_end);
+	mstart = max(range->start, map_start);
+	mend = min(range->end, map_end);
 	pr_debug("map %d+%d (%lx %lx), range %lx %lx, mrange %lx %lx\n",
-			map->index, map->count,
-			map->vma->vm_start, map->vma->vm_end,
-			range->start, range->end, mstart, mend);
-	err = unmap_grant_pages(map,
-				(mstart - map->vma->vm_start) >> PAGE_SHIFT,
-				(mend - mstart) >> PAGE_SHIFT);
-	WARN_ON(err);
+		 map->index, map->count, map_start, map_end,
+		 range->start, range->end, mstart, mend);
+	unmap_grant_pages(map, (mstart - map_start) >> PAGE_SHIFT,
+			  (mend - mstart) >> PAGE_SHIFT);
 
 	return true;
 }
@@ -519,6 +594,8 @@ static int gntdev_open(struct inode *inode, struct file *flip)
 	INIT_LIST_HEAD(&priv->maps);
 	mutex_init(&priv->lock);
 
+	mutex_init(&priv->batch_lock);
+
 #ifdef CONFIG_XEN_GNTDEV_DMABUF
 	priv->dmabuf_priv = gntdev_dmabuf_init(flip);
 	if (IS_ERR(priv->dmabuf_priv)) {
@@ -543,6 +620,7 @@ static int gntdev_release(struct inode *inode, struct file *flip)
 {
 	struct gntdev_priv *priv = flip->private_data;
 	struct gntdev_grant_map *map;
+	struct gntdev_copy_batch *batch;
 
 	pr_debug("priv %p\n", priv);
 
@@ -555,6 +633,14 @@ static int gntdev_release(struct inode *inode, struct file *flip)
 	}
 	mutex_unlock(&priv->lock);
 
+	mutex_lock(&priv->batch_lock);
+	while (priv->batch) {
+		batch = priv->batch;
+		priv->batch = batch->next;
+		kfree(batch);
+	}
+	mutex_unlock(&priv->batch_lock);
+
 #ifdef CONFIG_XEN_GNTDEV_DMABUF
 	gntdev_dmabuf_fini(priv->dmabuf_priv);
 #endif
@@ -720,17 +806,6 @@ static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u)
 	return rc;
 }
 
-#define GNTDEV_COPY_BATCH 16
-
-struct gntdev_copy_batch {
-	struct gnttab_copy ops[GNTDEV_COPY_BATCH];
-	struct page *pages[GNTDEV_COPY_BATCH];
-	s16 __user *status[GNTDEV_COPY_BATCH];
-	unsigned int nr_ops;
-	unsigned int nr_pages;
-	bool writeable;
-};
-
 static int gntdev_get_page(struct gntdev_copy_batch *batch, void __user *virt,
 				unsigned long *gfn)
 {
@@ -888,36 +963,53 @@ static int gntdev_grant_copy_seg(struct gntdev_copy_batch *batch,
 static long gntdev_ioctl_grant_copy(struct gntdev_priv *priv, void __user *u)
 {
 	struct ioctl_gntdev_grant_copy copy;
-	struct gntdev_copy_batch batch;
+	struct gntdev_copy_batch *batch;
 	unsigned int i;
 	int ret = 0;
 
 	if (copy_from_user(&copy, u, sizeof(copy)))
 		return -EFAULT;
 
-	batch.nr_ops = 0;
-	batch.nr_pages = 0;
+	mutex_lock(&priv->batch_lock);
+	if (!priv->batch) {
+		batch = kmalloc(sizeof(*batch), GFP_KERNEL);
+	} else {
+		batch = priv->batch;
+		priv->batch = batch->next;
+	}
+	mutex_unlock(&priv->batch_lock);
+	if (!batch)
+		return -ENOMEM;
+
+	batch->nr_ops = 0;
+	batch->nr_pages = 0;
 
 	for (i = 0; i < copy.count; i++) {
 		struct gntdev_grant_copy_segment seg;
 
 		if (copy_from_user(&seg, &copy.segments[i], sizeof(seg))) {
 			ret = -EFAULT;
+			gntdev_put_pages(batch);
 			goto out;
 		}
 
-		ret = gntdev_grant_copy_seg(&batch, &seg, &copy.segments[i].status);
-		if (ret < 0)
+		ret = gntdev_grant_copy_seg(batch, &seg, &copy.segments[i].status);
+		if (ret < 0) {
+			gntdev_put_pages(batch);
 			goto out;
+		}
 
 		cond_resched();
 	}
-	if (batch.nr_ops)
-		ret = gntdev_copy(&batch);
-	return ret;
+	if (batch->nr_ops)
+		ret = gntdev_copy(batch);
+
+ out:
+	mutex_lock(&priv->batch_lock);
+	batch->next = priv->batch;
+	priv->batch = batch;
+	mutex_unlock(&priv->batch_lock);
 
-  out:
-	gntdev_put_pages(&batch);
 	return ret;
 }
 
@@ -945,7 +1037,7 @@ static long gntdev_ioctl(struct file *flip,
 
 #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);
@@ -977,22 +1069,23 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
 		return -EINVAL;
 
 	pr_debug("map %d+%d at %lx (pgoff %lx)\n",
-			index, count, vma->vm_start, vma->vm_pgoff);
+		 index, count, vma->vm_start, vma->vm_pgoff);
 
 	mutex_lock(&priv->lock);
 	map = gntdev_find_map_index(priv, index, count);
 	if (!map)
 		goto unlock_out;
-	if (use_ptemod && map->vma)
+	if (!atomic_add_unless(&map->in_use, 1, 1))
 		goto unlock_out;
+
 	refcount_inc(&map->users);
 
 	vma->vm_ops = &gntdev_vmops;
 
-	vma->vm_flags |= VM_DONTEXPAND | VM_DONTDUMP | VM_MIXEDMAP;
+	vm_flags_set(vma, VM_DONTEXPAND | VM_DONTDUMP | VM_MIXEDMAP);
 
-	if (use_ptemod)
-		vma->vm_flags |= VM_DONTCOPY;
+	if (xen_pv_domain())
+		vm_flags_set(vma, VM_DONTCOPY);
 
 	vma->vm_private_data = map;
 	if (map->flags) {
@@ -1005,19 +1098,20 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
 			map->flags |= GNTMAP_readonly;
 	}
 
-	if (use_ptemod) {
-		map->vma = vma;
+	map->pages_vm_start = vma->vm_start;
+
+	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);
-		if (err) {
-			map->vma = NULL;
+		if (err)
 			goto out_unlock_put;
-		}
+
+		map->notifier_init = true;
 	}
 	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
@@ -1030,7 +1124,6 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
 		 */
 		mmu_interval_read_begin(&map->notifier);
 
-		map->pages_vm_start = vma->vm_start;
 		err = apply_to_page_range(vma->vm_mm, vma->vm_start,
 					  vma->vm_end - vma->vm_start,
 					  find_grant_ptes, map);
@@ -1044,7 +1137,7 @@ static int gntdev_mmap(struct file *flip, struct vm_area_struct *vma)
 	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;
@@ -1059,13 +1152,8 @@ unlock_out:
 out_unlock_put:
 	mutex_unlock(&priv->lock);
 out_put_map:
-	if (use_ptemod) {
+	if (xen_pv_domain())
 		unmap_grant_pages(map, 0, map->count);
-		if (map->vma) {
-			mmu_interval_notifier_remove(&map->notifier);
-			map->vma = NULL;
-		}
-	}
 	gntdev_put_map(priv, map);
 	return err;
 }
@@ -1093,8 +1181,6 @@ static int __init gntdev_init(void)
 	if (!xen_domain())
 		return -ENODEV;
 
-	use_ptemod = !xen_feature(XENFEAT_auto_translated_physmap);
-
 	err = misc_register(&gntdev_miscdev);
 	if (err != 0) {
 		pr_err("Could not register gntdev device\n");