dma-buf: Release module reference on creation failure

If we fail to create the anon file, we need to remember to release the
module reference on the owner.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
Cc: Sumit Semwal <sumit.semwal@linaro.org>
Cc: Daniel Vetter <daniel.vetter@ffwll.ch>
Cc: linux-media@vger.kernel.org
Cc: dri-devel@lists.freedesktop.org
Cc: linaro-mm-sig@lists.linaro.org
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: http://patchwork.freedesktop.org/patch/msgid/1468840582-21469-1-git-send-email-chris@chris-wilson.co.uk

drivers/dma-buf/dma-buf.c

@@ -334,6 +334,7 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
 	struct reservation_object *resv = exp_info->resv;
 	struct file *file;
 	size_t alloc_size = sizeof(struct dma_buf);
+	int ret;
 
 	if (!exp_info->resv)
 		alloc_size += sizeof(struct reservation_object);
@@ -357,8 +358,8 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
 
 	dmabuf = kzalloc(alloc_size, GFP_KERNEL);
 	if (!dmabuf) {
-		module_put(exp_info->owner);
-		return ERR_PTR(-ENOMEM);
+		ret = -ENOMEM;
+		goto err_module;
 	}
 
 	dmabuf->priv = exp_info->priv;
@@ -379,8 +380,8 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
 	file = anon_inode_getfile("dmabuf", &dma_buf_fops, dmabuf,
 					exp_info->flags);
 	if (IS_ERR(file)) {
-		kfree(dmabuf);
-		return ERR_CAST(file);
+		ret = PTR_ERR(file);
+		goto err_dmabuf;
 	}
 
 	file->f_mode |= FMODE_LSEEK;
@@ -394,6 +395,12 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
 	mutex_unlock(&db_list.lock);
 
 	return dmabuf;
+
+err_dmabuf:
+	kfree(dmabuf);
+err_module:
+	module_put(exp_info->owner);
+	return ERR_PTR(ret);
 }
 EXPORT_SYMBOL_GPL(dma_buf_export);