xen-gntdev: Use find_vma rather than iterating our vma list manually

This should be faster if many mappings exist, and also removes
the only user of map->vma not related to PTE modification.

Signed-off-by: Daniel De Graaf <dgdegra@tycho.nsa.gov>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 8 insertions, 24 deletions

diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index 23d208a219fa..ce8c37c2b673 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -167,23 +167,6 @@ static struct grant_map *gntdev_find_map_index(struct gntdev_priv *priv,
         return NULL;
 }
 
-static struct grant_map *gntdev_find_map_vaddr(struct gntdev_priv *priv,
-                                               unsigned long vaddr)
-{
-        struct grant_map *map;
-
-        list_for_each_entry(map, &priv->maps, next) {
-                if (!map->vma)
-                        continue;
-                if (vaddr < map->vma->vm_start)
-                        continue;
-                if (vaddr >= map->vma->vm_end)
-                        continue;
-                return map;
-        }
-        return NULL;
-}
-
 static int gntdev_del_map(struct grant_map *map)
 {
         int i;
@@ -494,22 +477,23 @@ static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv,
                                               struct ioctl_gntdev_get_offset_for_vaddr __user *u)
 {
         struct ioctl_gntdev_get_offset_for_vaddr op;
+        struct vm_area_struct *vma;
         struct grant_map *map;
 
         if (copy_from_user(&op, u, sizeof(op)) != 0)
                 return -EFAULT;
         pr_debug("priv %p, offset for vaddr %lx\n", priv, (unsigned long)op.vaddr);
 
-        spin_lock(&priv->lock);
-        map = gntdev_find_map_vaddr(priv, op.vaddr);
-        if (map == NULL ||
-            map->vma->vm_start != op.vaddr) {
-                spin_unlock(&priv->lock);
+        vma = find_vma(current->mm, op.vaddr);
+        if (!vma || vma->vm_ops != &gntdev_vmops)
                 return -EINVAL;
-        }
+
+        map = vma->vm_private_data;
+        if (!map)
+                return -EINVAL;
+
         op.offset = map->index << PAGE_SHIFT;
         op.count = map->count;
-        spin_unlock(&priv->lock);
 
         if (copy_to_user(u, &op, sizeof(op)) != 0)
                 return -EFAULT;