[REBASE PATCH v5 9/9] xen/privcmd-buf.c: Convert to use vm_map_pages_zero()

[Souptick Joarder]

Convert to use vm_map_pages_zero() to map range of kernel
memory to user vma.

This driver has ignored vm_pgoff. We could later "fix" these drivers
to behave according to the normal vm_pgoff offsetting simply by
removing the _zero suffix on the function name and if that causes
regressions, it gives us an easy way to revert.

Signed-off-by: Souptick Joarder <jrdr.linux at gmail.com>
Reviewed-by: Boris Ostrovsky <boris.ostrovsky at oracle.com>
---
 drivers/xen/privcmd-buf.c | 8 ++------
 1 file changed, 2 insertions(+), 6 deletions(-)

diff --git a/drivers/xen/privcmd-buf.c b/drivers/xen/privcmd-buf.c
index de01a6d..d02dc43 100644
--- a/drivers/xen/privcmd-buf.c
+++ b/drivers/xen/privcmd-buf.c
@@ -166,12 +166,8 @@ static int privcmd_buf_mmap(struct file *file, struct vm_area_struct *vma)
 	if (vma_priv->n_pages != count)
 		ret = -ENOMEM;
 	else
-		for (i = 0; i < vma_priv->n_pages; i++) {
-			ret = vm_insert_page(vma, vma->vm_start + i * PAGE_SIZE,
-					     vma_priv->pages[i]);
-			if (ret)
-				break;
-		}
+		ret = vm_map_pages_zero(vma, vma_priv->pages,
+						vma_priv->n_pages);
 
 	if (ret)
 		privcmd_buf_vmapriv_free(vma_priv);
-- 
1.9.1