drm/gem: add mutex lock when using drm_gem_mmap_obj

The drm_gem_mmap_obj() has to be protected with dev->struct_mutex,
but some caller functions do not. So it adds mutex lock to missing
callers and adds assertion to check whether drm_gem_mmap_obj() is
called with mutex lock or not.

Signed-off-by: YoungJun Cho <yj44.cho@samsung.com>
Signed-off-by: Seung-Woo Kim <sw0312.kim@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Rob Clark <robdclark@gmail.com>
Reviewed-by: Maarten Lankhorst <maarten.lankhorst@canonical.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 3 insertions, 0 deletions

diff --git a/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c b/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
index 3256693de110..4fcca8d42796 100644
--- a/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
+++ b/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
@@ -140,12 +140,15 @@ static int omap_gem_dmabuf_mmap(struct dma_buf *buffer,
                 struct vm_area_struct *vma)
 {
         struct drm_gem_object *obj = buffer->priv;
+        struct drm_device *dev = obj->dev;
         int ret = 0;
 
         if (WARN_ON(!obj->filp))
                 return -EINVAL;
 
+        mutex_lock(&dev->struct_mutex);
         ret = drm_gem_mmap_obj(obj, omap_gem_mmap_size(obj), vma);
+        mutex_unlock(&dev->struct_mutex);
         if (ret < 0)
                 return ret;