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From: "Sinclair Yeh" <syeh@vmware.com>
To: stable@vger.kernel.org
Cc: Sinclair Yeh <syeh@vmware.com>
Subject: [PATCH 3/3] drm/vmwgfx: Fix order of operation
Date: Tue, 31 May 2016 11:17:14 -0700	[thread overview]
Message-ID: <1464718634-4494-3-git-send-email-syeh@vmware.com> (raw)
In-Reply-To: <1464718634-4494-1-git-send-email-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>
Cc: <stable@vger.kernel.org> # 4.4.10-
---
 drivers/gpu/drm/vmwgfx/vmwgfx_fb.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c b/drivers/gpu/drm/vmwgfx/vmwgfx_fb.c
index 3b1faf7..679a4cb 100644
--- 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 *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;
 	}
-- 
2.8.2


      parent reply	other threads:[~2016-05-31 18:18 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-05-31 18:17 [PATCH 1/3] drm/vmwgfx: Enable SVGA_3D_CMD_DX_SET_PREDICATION Sinclair Yeh
2016-05-31 18:17 ` [PATCH 2/3] drm/vmwgfx: use vmw_cmd_dx_cid_check for query commands Sinclair Yeh
2016-05-31 18:17 ` Sinclair Yeh [this message]

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