diff options
| -rw-r--r-- | drivers/xen/gntdev.c | 29 |
1 files changed, 24 insertions, 5 deletions
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c index 2e22df2..cca62cc8 100644 --- a/drivers/xen/gntdev.c +++ b/drivers/xen/gntdev.c @@ -378,7 +378,20 @@ static void gntdev_vma_close(struct vm_area_struct *vma) struct grant_map *map = vma->vm_private_data; pr_debug("gntdev_vma_close %p\n", vma); - map->vma = NULL; + if (use_ptemod) { + struct file *file = vma->vm_file; + struct gntdev_priv *priv = file->private_data; + /* It is possible that an mmu notifier could be running + * concurrently, so take priv->lock to ensure that the vma won't + * vanishing during the unmap_grant_pages call, since we will + * spin here until that completes. Such a concurrent call will + * not do any unmapping, since that has been done prior to + * closing the vma, but it may still iterate the unmap_ops list. + */ + spin_lock(&priv->lock); + map->vma = NULL; + spin_unlock(&priv->lock); + } vma->vm_private_data = NULL; gntdev_put_map(map); } @@ -579,25 +592,31 @@ static long gntdev_ioctl_get_offset_for_vaddr(struct gntdev_priv *priv, struct ioctl_gntdev_get_offset_for_vaddr op; struct vm_area_struct *vma; struct grant_map *map; + int rv = -EINVAL; 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); + down_read(¤t->mm->mmap_sem); vma = find_vma(current->mm, op.vaddr); if (!vma || vma->vm_ops != &gntdev_vmops) - return -EINVAL; + goto out_unlock; map = vma->vm_private_data; if (!map) - return -EINVAL; + goto out_unlock; op.offset = map->index << PAGE_SHIFT; op.count = map->count; + rv = 0; - if (copy_to_user(u, &op, sizeof(op)) != 0) + out_unlock: + up_read(¤t->mm->mmap_sem); + + if (rv == 0 && copy_to_user(u, &op, sizeof(op)) != 0) return -EFAULT; - return 0; + return rv; } static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u) |