diff options
| -rw-r--r-- | drivers/dma-buf/dma-buf.c | 27 | ||||
| -rw-r--r-- | include/linux/dma-buf.h | 13 |
2 files changed, 38 insertions, 2 deletions
diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 3ae6c0c2cc02..f4104a21b069 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -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); diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h index a0bd071466fc..8a327566d7f4 100644 --- a/include/linux/dma-buf.h +++ b/include/linux/dma-buf.h @@ -45,6 +45,15 @@ struct dma_buf_attachment; */ 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: * * This is called from dma_buf_attach() to make sure that a given @@ -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; }; |