1 files changed, 35 insertions, 4 deletions

diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
index 7c858020d14b..f4104a21b069 100644
--- a/drivers/dma-buf/dma-buf.c
+++ b/drivers/dma-buf/dma-buf.c
@@ -90,6 +90,10 @@ static int dma_buf_mmap_internal(struct file *file, struct vm_area_struct *vma)
 
 	dmabuf = file->private_data;
 
+	/* check if buffer supports mmap */
+	if (!dmabuf->ops->mmap)
+		return -EINVAL;
+
 	/* check for overflowing the buffer's size */
 	if (vma->vm_pgoff + vma_pages(vma) >
 	    dmabuf->size >> PAGE_SHIFT)
@@ -404,8 +408,7 @@ struct dma_buf *dma_buf_export(const struct dma_buf_export_info *exp_info)
 			  || !exp_info->ops
 			  || !exp_info->ops->map_dma_buf
 			  || !exp_info->ops->unmap_dma_buf
-			  || !exp_info->ops->release
-			  || !exp_info->ops->mmap)) {
+			  || !exp_info->ops->release)) {
 		return ERR_PTR(-EINVAL);
 	}
 
@@ -573,6 +576,7 @@ struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf,
 	list_add(&attach->node, &dmabuf->attachments);
 
 	mutex_unlock(&dmabuf->lock);
+
 	return attach;
 
 err_attach:
@@ -595,6 +599,9 @@ void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach)
 	if (WARN_ON(!dmabuf || !attach))
 		return;
 
+	if (attach->sgt)
+		dmabuf->ops->unmap_dma_buf(attach, attach->sgt, attach->dir);
+
 	mutex_lock(&dmabuf->lock);
 	list_del(&attach->node);
 	if (dmabuf->ops->detach)
@@ -630,10 +637,27 @@ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach,
 	if (WARN_ON(!attach || !attach->dmabuf))
 		return ERR_PTR(-EINVAL);
 
+	if (attach->sgt) {
+		/*
+		 * Two mappings with different directions for the same
+		 * attachment are not allowed.
+		 */
+		if (attach->dir != direction &&
+		    attach->dir != DMA_BIDIRECTIONAL)
+			return ERR_PTR(-EBUSY);
+
+		return attach->sgt;
+	}
+
 	sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction);
 	if (!sg_table)
 		sg_table = ERR_PTR(-ENOMEM);
 
+	if (!IS_ERR(sg_table) && attach->dmabuf->ops->cache_sgt_mapping) {
+		attach->sgt = sg_table;
+		attach->dir = direction;
+	}
+
 	return sg_table;
 }
 EXPORT_SYMBOL_GPL(dma_buf_map_attachment);
@@ -657,8 +681,10 @@ void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
 	if (WARN_ON(!attach || !attach->dmabuf || !sg_table))
 		return;
 
-	attach->dmabuf->ops->unmap_dma_buf(attach, sg_table,
-						direction);
+	if (attach->sgt == sg_table)
+		return;
+
+	attach->dmabuf->ops->unmap_dma_buf(attach, sg_table, direction);
 }
 EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment);
 
@@ -906,6 +932,10 @@ int dma_buf_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma,
 	if (WARN_ON(!dmabuf || !vma))
 		return -EINVAL;
 
+	/* check if buffer supports mmap */
+	if (!dmabuf->ops->mmap)
+		return -EINVAL;
+
 	/* check for offset overflow */
 	if (pgoff + vma_pages(vma) < pgoff)
 		return -EOVERFLOW;
@@ -1068,6 +1098,7 @@ static int dma_buf_debug_show(struct seq_file *s, void *unused)
 				   fence->ops->get_driver_name(fence),
 				   fence->ops->get_timeline_name(fence),
 				   dma_fence_is_signaled(fence) ? "" : "un");
+			dma_fence_put(fence);
 		}
 		rcu_read_unlock();