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

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

[Souptick Joarder]

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@gmail.com>
---
 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

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

[Souptick Joarder]

While using mmap, the incorrect values of length and vm_pgoff are
ignored and this driver goes 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@gmail.com>
---
v2: Fixed minor typo.

 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

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

[Miguel Ojeda]

On Sun, May 26, 2019 at 6:05 PM Souptick Joarder <jrdr.linux@gmail.com> wrote:
>
> While using mmap, the incorrect values of length and vm_pgoff are
> ignored and this driver goes 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@gmail.com>
> ---
> v2: Fixed minor typo.

Almost forgot about these two -- picking both v2s for a PR later. Not
sure what happened with the mm/ related one I sent, is it in Andrew's
tree?

Cheers,
Miguel