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Commit f13e143e authored by Christian König's avatar Christian König
Browse files

dma-buf: start caching of sg_table objects v2 



To allow a smooth transition from pinning buffer objects to dynamic
invalidation we first start to cache the sg_table for an attachment.

v2: keep closer to the DRM implementation

Signed-off-by: default avatarChristian König <christian.koenig@amd.com>
Reviewed-by: default avatarDaniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.kernel.org/patch/10943053/
parent 0c7b178a

drivers/dma-buf/dma-buf.c

+25 −2
Original line number Original line Diff line number Diff line
@@ -576,6 +576,7 @@ struct dma_buf_attachment *dma_buf_attach(struct dma_buf *dmabuf, 
	list_add(&attach->node, &dmabuf->attachments);

	list_add(&attach->node, &dmabuf->attachments);





	mutex_unlock(&dmabuf->lock);

	mutex_unlock(&dmabuf->lock);



	return attach;

	return attach;





err_attach:

err_attach:
@@ -598,6 +599,9 @@ void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach) 
	if (WARN_ON(!dmabuf || !attach))

	if (WARN_ON(!dmabuf || !attach))

		return;

		return;





	if (attach->sgt)

		dmabuf->ops->unmap_dma_buf(attach, attach->sgt, attach->dir);



	mutex_lock(&dmabuf->lock);

	mutex_lock(&dmabuf->lock);

	list_del(&attach->node);

	list_del(&attach->node);

	if (dmabuf->ops->detach)

	if (dmabuf->ops->detach)
@@ -633,10 +637,27 @@ struct sg_table *dma_buf_map_attachment(struct dma_buf_attachment *attach, 
	if (WARN_ON(!attach || !attach->dmabuf))

	if (WARN_ON(!attach || !attach->dmabuf))

		return ERR_PTR(-EINVAL);

		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);

	sg_table = attach->dmabuf->ops->map_dma_buf(attach, direction);

	if (!sg_table)

	if (!sg_table)

		sg_table = ERR_PTR(-ENOMEM);

		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;

	return sg_table;

}

}

EXPORT_SYMBOL_GPL(dma_buf_map_attachment);

EXPORT_SYMBOL_GPL(dma_buf_map_attachment);
@@ -660,8 +681,10 @@ void dma_buf_unmap_attachment(struct dma_buf_attachment *attach, 
	if (WARN_ON(!attach || !attach->dmabuf || !sg_table))

	if (WARN_ON(!attach || !attach->dmabuf || !sg_table))

		return;

		return;





	attach->dmabuf->ops->unmap_dma_buf(attach, sg_table,

	if (attach->sgt == sg_table)

						direction);

		return;



	attach->dmabuf->ops->unmap_dma_buf(attach, sg_table, direction);

}

}

EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment);

EXPORT_SYMBOL_GPL(dma_buf_unmap_attachment);

include/linux/dma-buf.h

+13 −0
Original line number Original line Diff line number Diff line
@@ -44,6 +44,15 @@ struct dma_buf_attachment; 
 * @vunmap: [optional] unmaps a vmap from the buffer

 * @vunmap: [optional] unmaps a vmap from the buffer

 */

 */

struct dma_buf_ops {

struct dma_buf_ops {

	/**

	  * @cache_sgt_mapping:

	  *

	  * If true the framework will cache the first mapping made for each

	  * attachment. This avoids creating mappings for attachments multiple

	  * times.

	  */

	bool cache_sgt_mapping;



	/**

	/**

	 * @attach:

	 * @attach:

	 *

	 *
@@ -323,6 +332,8 @@ struct dma_buf { 
 * @dmabuf: buffer for this attachment.

 * @dmabuf: buffer for this attachment.

 * @dev: device attached to the buffer.

 * @dev: device attached to the buffer.

 * @node: list of dma_buf_attachment.

 * @node: list of dma_buf_attachment.

 * @sgt: cached mapping.

 * @dir: direction of cached mapping.

 * @priv: exporter specific attachment data.

 * @priv: exporter specific attachment data.

 *

 *

 * This structure holds the attachment information between the dma_buf buffer

 * This structure holds the attachment information between the dma_buf buffer
@@ -338,6 +349,8 @@ struct dma_buf_attachment { 
	struct dma_buf *dmabuf;

	struct dma_buf *dmabuf;

	struct device *dev;

	struct device *dev;

	struct list_head node;

	struct list_head node;

	struct sg_table *sgt;

	enum dma_data_direction dir;

	void *priv;

	void *priv;

};

};