[PATCH 4.4 75/99] drm/vmwgfx: Fix order of operation

Greg Kroah-Hartman
2016-06-05T21:50:33Z

From: Sinclair Yeh <syeh@vmware.com>

commit 7851496a32319237456919575e5f4ba62f74cc7d upstream.

mode->hdisplay * (var->bits_per_pixel + 7) gets evaluated before
the division, potentially making the pitch larger than it should
be.

Since the original intention is to do a div-round-up, just use
the macro instead.

Signed-off-by: Sinclair Yeh <syeh@vmware.com>
Reviewed-by: Thomas Hellstrom <thellstrom@vmware.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/gpu/drm/vmwgfx/vmwgfx_fb.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)

--- a/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c
+++ b/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c
@@ -573,9 +573,9 @@ static int vmw_fb_set_par(struct fb_info
mode = old_mode;
old_mode = NULL;
} else if (!vmw_kms_validate_mode_vram(vmw_priv,
- mode->hdisplay *
- (var->bits_per_pixel + 7) / 8,
- mode->vdisplay)) {
+ mode->hdisplay *
+ DIV_ROUND_UP(var->bits_per_pixel, 8),
+ mode->vdisplay)) {
drm_mode_destroy(vmw_priv->dev, mode);
return -EINVAL;
}