On Wed, Jun 26, 2013 at 7:39 PM, Seung-Woo Kim <sw0312.kim@xxxxxxxxxxx> wrote:
> From: YoungJun Cho <yj44.cho@xxxxxxxxxxx>
>
> 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.
Yeah, looks like since drm_gem_mmap_obj() is using
drm_vm_open_locked() (vs drm_vm_open() / vm_ops->open()), we need
this. I missed that when reviewing the original patch to
drm_gem_mmap_obj()'ify things.
Reviewed-by: Rob Clark <robdclark@xxxxxxxxx>
> Signed-off-by: YoungJun Cho <yj44.cho@xxxxxxxxxxx>
> Signed-off-by: Seung-Woo Kim <sw0312.kim@xxxxxxxxxxx>
> Signed-off-by: Kyungmin Park <kyungmin.park@xxxxxxxxxxx>
> CC: Laurent Pinchart <laurent.pinchart+renesas@xxxxxxxxxxxxxxxx>
> CC: Rob Clark <robdclark@xxxxxxxxx>
> ---
> This patch is based on drm-next branch.
>
> Changes since v1:
> - Use lockdep_assert_held() instead of mutex_is_locked() as Maarten commented
> - Fix commit message about assertion
>
> drivers/gpu/drm/drm_gem.c | 4 ++++
> drivers/gpu/drm/drm_gem_cma_helper.c | 3 +++
> drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c | 3 +++
> 3 files changed, 10 insertions(+)
>
> diff --git a/drivers/gpu/drm/drm_gem.c b/drivers/gpu/drm/drm_gem.c
> index 4321713..34c0be7 100644
> --- a/drivers/gpu/drm/drm_gem.c
> +++ b/drivers/gpu/drm/drm_gem.c
> @@ -661,6 +661,8 @@ EXPORT_SYMBOL(drm_gem_vm_close);
> * the GEM object is not looked up based on its fake offset. To implement the
> * DRM mmap operation, drivers should use the drm_gem_mmap() function.
> *
> + * NOTE: This function has to be protected with dev->struct_mutex
> + *
> * Return 0 or success or -EINVAL if the object size is smaller than the VMA
> * size, or if no gem_vm_ops are provided.
> */
> @@ -669,6 +671,8 @@ int drm_gem_mmap_obj(struct drm_gem_object *obj, unsigned long obj_size,
> {
> struct drm_device *dev = obj->dev;
>
> + lockdep_assert_held(&dev->struct_mutex);
> +
> /* Check for valid size. */
> if (obj_size < vma->vm_end - vma->vm_start)
> return -EINVAL;
> diff --git a/drivers/gpu/drm/drm_gem_cma_helper.c b/drivers/gpu/drm/drm_gem_cma_helper.c
> index 9efabce..ce06397 100644
> --- a/drivers/gpu/drm/drm_gem_cma_helper.c
> +++ b/drivers/gpu/drm/drm_gem_cma_helper.c
> @@ -487,9 +487,12 @@ static int drm_gem_cma_dmabuf_mmap(struct dma_buf *dmabuf,
> {
> struct drm_gem_cma_object *cma_obj = dmabuf->priv;
> struct drm_gem_object *gem_obj = &cma_obj->base;
> + struct drm_device *dev = gem_obj->dev;
> int ret;
>
> + mutex_lock(&dev->struct_mutex);
> ret = drm_gem_mmap_obj(gem_obj, gem_obj->size, vma);
> + mutex_unlock(&dev->struct_mutex);
> if (ret < 0)
> return ret;
>
> diff --git a/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c b/drivers/gpu/drm/omapdrm/omap_gem_dmabuf.c
> index 3256693..4fcca8d 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;
>
> --
> 1.7.9.5
>
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