On 12/14/2010 06:55 AM, Daniel De Graaf wrote:
> apply_to_page_range will acquire PTE lock while priv->lock is held, and
> mn_invl_range_start tries to acquire priv->lock with PTE already held.
> Fix by not holding priv->lock during the entire map operation.
Is priv->lock needed to protect the contents of map?
J
> Signed-off-by: Daniel De Graaf <dgdegra@xxxxxxxxxxxxx>
> ---
> drivers/xen/gntdev.c | 19 +++++++++----------
> 1 files changed, 9 insertions(+), 10 deletions(-)
>
> diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
> index a33e443..c582804 100644
> --- a/drivers/xen/gntdev.c
> +++ b/drivers/xen/gntdev.c
> @@ -581,23 +581,22 @@ static int gntdev_mmap(struct file *flip, struct
> vm_area_struct *vma)
> if (!(vma->vm_flags & VM_WRITE))
> map->flags |= GNTMAP_readonly;
>
> + spin_unlock(&priv->lock);
> +
> err = apply_to_page_range(vma->vm_mm, vma->vm_start,
> vma->vm_end - vma->vm_start,
> find_grant_ptes, map);
> - if (err) {
> - goto unlock_out;
> - if (debug)
> - printk("%s: find_grant_ptes() failure.\n",
> __FUNCTION__);
> - }
> + if (err)
> + return err;
>
> err = map_grant_pages(map);
> - if (err) {
> - goto unlock_out;
> - if (debug)
> - printk("%s: map_grant_pages() failure.\n",
> __FUNCTION__);
> - }
> + if (err)
> + return err;
> +
> map->is_mapped = 1;
>
> + return 0;
> +
> unlock_out:
> spin_unlock(&priv->lock);
> return err;
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