[PATCH 07/18] drm/mga200g: Hold a proper reference for cursor_set

[Thierry Reding]

On Thu, Jul 09, 2015 at 11:32:39PM +0200, Daniel Vetter wrote:
> Looking up an obj, immediate dropping the acquired reference and then
> continuing to use it isn't how this is supposed to work. Fix this by
> holding a reference for the entire function.
> 
> While at it stop grabbing dev->struct_mutex, it doesn't protect
> anything here.
> 
> Signed-off-by: Daniel Vetter 
> ---
>  drivers/gpu/drm/mgag200/mgag200_cursor.c | 22 ++
>  1 file changed, 10 insertions(+), 12 deletions(-)

Reviewed-by: Thierry Reding 
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[PATCH 07/18] drm/mga200g: Hold a proper reference for cursor_set

[Daniel Vetter]

Looking up an obj, immediate dropping the acquired reference and then
continuing to use it isn't how this is supposed to work. Fix this by
holding a reference for the entire function.

While at it stop grabbing dev->struct_mutex, it doesn't protect
anything here.

Signed-off-by: Daniel Vetter 
---
 drivers/gpu/drm/mgag200/mgag200_cursor.c | 22 ++
 1 file changed, 10 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/mgag200/mgag200_cursor.c 
b/drivers/gpu/drm/mgag200/mgag200_cursor.c
index 9f9780b7ddf0..4f2068fe5d88 100644
--- a/drivers/gpu/drm/mgag200/mgag200_cursor.c
+++ b/drivers/gpu/drm/mgag200/mgag200_cursor.c
@@ -70,18 +70,22 @@ int mga_crtc_cursor_set(struct drm_crtc *crtc,
BUG_ON(pixels_2 != pixels_current && pixels_2 != pixels_prev);
BUG_ON(pixels_current == pixels_prev);

+   obj = drm_gem_object_lookup(dev, file_priv, handle);
+   if (!obj)
+   return -ENOENT;
+
ret = mgag200_bo_reserve(pixels_1, true);
if (ret) {
WREG8(MGA_CURPOSXL, 0);
WREG8(MGA_CURPOSXH, 0);
-   return ret;
+   goto out_unref;
}
ret = mgag200_bo_reserve(pixels_2, true);
if (ret) {
WREG8(MGA_CURPOSXL, 0);
WREG8(MGA_CURPOSXH, 0);
mgag200_bo_unreserve(pixels_1);
-   return ret;
+   goto out_unreserve1;
}

if (!handle) {
@@ -106,16 +110,6 @@ int mga_crtc_cursor_set(struct drm_crtc *crtc,
}
}

-   mutex_lock(>struct_mutex);
-   obj = drm_gem_object_lookup(dev, file_priv, handle);
-   if (!obj) {
-   mutex_unlock(>struct_mutex);
-   ret = -ENOENT;
-   goto out1;
-   }
-   drm_gem_object_unreference(obj);
-   mutex_unlock(>struct_mutex);
-
bo = gem_to_mga_bo(obj);
ret = mgag200_bo_reserve(bo, true);
if (ret) {
@@ -252,7 +246,11 @@ int mga_crtc_cursor_set(struct drm_crtc *crtc,
if (ret)
mga_hide_cursor(mdev);
mgag200_bo_unreserve(pixels_1);
+out_unreserve1:
mgag200_bo_unreserve(pixels_2);
+out_unref:
+   drm_gem_object_unreference_unlocked(obj);
+
return ret;
 }

-- 
2.1.4