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dma-buf: start caching of sg_table objects v2

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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: Christian König <christian.koenig@amd.com>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.kernel.org/patch/10943053/
This commit is contained in:
Christian König 2018-07-03 16:42:26 +02:00
parent 0c7b178ad7
commit f13e143e74
2 changed files with 38 additions and 2 deletions
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27
drivers/dma-buf/dma-buf.c
View File

@ -576,6 +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:
@ -598,6 +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)
@ -633,10 +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);
@ -660,8 +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);

13
include/linux/dma-buf.h
View File

@ -44,6 +44,15 @@ struct dma_buf_attachment;
* @vunmap: [optional] unmaps a vmap from the buffer
*/
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:
*
@ -323,6 +332,8 @@ struct dma_buf {
* @dmabuf: buffer for this attachment.
* @dev: device attached to the buffer.
* @node: list of dma_buf_attachment.
* @sgt: cached mapping.
* @dir: direction of cached mapping.
* @priv: exporter specific attachment data.
*
* This structure holds the attachment information between the dma_buf buffer
@ -338,6 +349,8 @@ struct dma_buf_attachment {
struct dma_buf *dmabuf;
struct device *dev;
struct list_head node;
struct sg_table *sgt;
enum dma_data_direction dir;
void *priv;
};