dma-buf: Remove unneeded sanity checks

ops, ops->map_dma_buf and ops->unmap_dma_buf are guaranteed to be
non-NULL by a check in dma_buf_export(). Remove NULL checks on those
variables in the other API functions.

Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Sumit Semwal <sumit.semwal@linaro.org>

drivers/base/dma-buf.c

@@ -185,7 +185,7 @@ struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
 	struct dma_buf_attachment *attach;
 	int ret;
 
-	if (WARN_ON(!dmabuf || !dev || !dmabuf->ops))
+	if (WARN_ON(!dmabuf || !dev))
 		return ERR_PTR(-EINVAL);
 
 	attach = kzalloc(sizeof(struct dma_buf_attachment), GFP_KERNEL);
@@ -224,7 +224,7 @@ EXPORT_SYMBOL_GPL(dma_buf_attach);
  */
 void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
 {
-	if (WARN_ON(!dmabuf || !attach || !dmabuf->ops))
+	if (WARN_ON(!dmabuf || !attach))
 		return;
 
 	mutex_lock(&dmabuf->lock);
@@ -255,12 +255,11 @@ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
 
 	might_sleep();
 
-	if (WARN_ON(!attach || !attach->dmabuf || !attach->dmabuf->ops))
+	if (WARN_ON(!attach || !attach->dmabuf))
 		return ERR_PTR(-EINVAL);
 
 	mutex_lock(&attach->dmabuf->lock);
-	if (attach->dmabuf->ops->map_dma_buf)
-		sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction);
+	sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction);
 	mutex_unlock(&attach->dmabuf->lock);
 
 	return sg_table;
@@ -278,13 +277,11 @@ EXPORT_SYMBOL_GPL(dma_buf_map_attachment);
 void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
 				struct sg_table *sg_table)
 {
-	if (WARN_ON(!attach || !attach->dmabuf || !sg_table
-			    || !attach->dmabuf->ops))
+	if (WARN_ON(!attach || !attach->dmabuf || !sg_table))
 		return;
 
 	mutex_lock(&attach->dmabuf->lock);
-	if (attach->dmabuf->ops->unmap_dma_buf)
-		attach->dmabuf->ops->unmap_dma_buf(attach, sg_table);
+	attach->dmabuf->ops->unmap_dma_buf(attach, sg_table);
 	mutex_unlock(&attach->dmabuf->lock);
 
 }