[PATCH 1/2] auxdisplay/cfag12864bfb.c: Convert to use vm_map_pages_zero()

From: Souptick Joarder
Date: Mon May 20 2019 - 11:27:18 EST


While using mmap, the incorrect value of length and vm_pgoff are
ignored and this driver go ahead with mapping cfag12864b_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>
---
drivers/auxdisplay/cfag12864bfb.c | 5 +++--
1 file changed, 3 insertions(+), 2 deletions(-)

diff --git a/drivers/auxdisplay/cfag12864bfb.c b/drivers/auxdisplay/cfag12864bfb.c
index 40c8a55..4074886 100644
--- a/drivers/auxdisplay/cfag12864bfb.c
+++ b/drivers/auxdisplay/cfag12864bfb.c
@@ -52,8 +52,9 @@

static int cfag12864bfb_mmap(struct fb_info *info, struct vm_area_struct *vma)
{
- return vm_insert_page(vma, vma->vm_start,
- virt_to_page(cfag12864b_buffer));
+ struct page *pages = virt_to_page(cfag12864b_buffer);
+
+ return vm_map_pages_zero(vma, &pages, 1);
}

static struct fb_ops cfag12864bfb_ops = {
--
1.9.1