[PATCH 2/2] auxdisplay/ht16k33.c: Convert to use vm_map_pages_zero()

From: Souptick Joarder
Date: Sun May 26 2019 - 12:09:25 EST

While using mmap, the incorrect values of length and vm_pgoff are
ignored and this driver goes ahead with mapping fbdev.buffer
to user vma.

Convert vm_insert_pages() to use vm_map_pages_zero(). 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@xxxxxxxxx>
Acked-by: Robin van der Gracht <robin@xxxxxxxxxxx>
v2: Fixed minor typo. Acked-by tag added.

drivers/auxdisplay/ht16k33.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/auxdisplay/ht16k33.c b/drivers/auxdisplay/ht16k33.c
index 21393ec..9c0bb77 100644
--- a/drivers/auxdisplay/ht16k33.c
+++ b/drivers/auxdisplay/ht16k33.c
@@ -223,9 +223,9 @@ static int ht16k33_bl_check_fb(struct backlight_device *bl, struct fb_info *fi)
static int ht16k33_mmap(struct fb_info *info, struct vm_area_struct *vma)
struct ht16k33_priv *priv = info->par;
+ struct page *pages = virt_to_page(priv->fbdev.buffer);

- return vm_insert_page(vma, vma->vm_start,
- virt_to_page(priv->fbdev.buffer));
+ return vm_map_pages_zero(vma, &pages, 1);

static struct fb_ops ht16k33_fb_ops = {