On Fri, Apr 26, 2019 at 02:36:29PM +0200, Christian König wrote:
> To allow a smooth transition from pinning buffer objects to dynamic
> invalidation we first start to cache the sg_table for an attachment
> unless the driver has implemented the explicite pin/unpin callbacks.
>
> Signed-off-by: Christian König <christian.koenig@xxxxxxx>
Correction on my "squash everything" suggestion: I think this patch here
still needs to be separate, so that "why did this cause a regression" is
easier to understand. But with a small nit.
> ---
> drivers/dma-buf/dma-buf.c | 24 ++++++++++++++++++++++++
> include/linux/dma-buf.h | 1 +
> 2 files changed, 25 insertions(+)
>
> diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c
> index 0656dcf289be..a18d10c4425a 100644
> --- a/drivers/dma-buf/dma-buf.c
> +++ b/drivers/dma-buf/dma-buf.c
> @@ -610,6 +610,20 @@ dma_buf_attach(const struct dma_buf_attach_info *info)
> list_add(&attach->node, &dmabuf->attachments);
>
> mutex_unlock(&dmabuf->lock);
> +
> + if (!dmabuf->ops->pin) {
I think a static inline dma_buf_is_dynamic_attachment() would be good
here, which in this patch (since it's ealier) would always return false.
Aside: I think only checking pin here (i.e. can the exporter do dynamic
mappings) isn't good enough, we also need to check for the importers
->invalidate. Hence _is_dynamic_attachment, not _is_dynamic_dma_buf. If we
don't also check for the importer we again have a reservation lock in
dma_buf_map/unmap, which we know will anger the lockdep gods ...
-Daniel
> + struct sg_table *sgt;
> +
> + sgt = dmabuf->ops->map_dma_buf(attach, DMA_BIDIRECTIONAL);
> + if (!sgt)
> + sgt = ERR_PTR(-ENOMEM);
> + if (IS_ERR(sgt)) {
> + dma_buf_detach(dmabuf, attach);
> + return ERR_CAST(sgt);
> + }
> + attach->sgt = sgt;
> + }
> +
> return attach;
>
> err_attach:
> @@ -632,6 +646,10 @@ 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,
> + DMA_BIDIRECTIONAL);
> +
> mutex_lock(&dmabuf->lock);
> list_del(&attach->node);
> if (dmabuf->ops->detach)
> @@ -668,6 +686,9 @@ 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)
> + return attach->sgt;
> +
> reservation_object_lock(attach->dmabuf->resv, NULL);
> r = dma_buf_pin(attach->dmabuf);
> reservation_object_unlock(attach->dmabuf->resv);
> @@ -701,6 +722,9 @@ void dma_buf_unmap_attachment(struct dma_buf_attachment *attach,
> if (WARN_ON(!attach || !attach->dmabuf || !sg_table))
> return;
>
> + if (attach->sgt == sg_table)
> + return;
> +
> attach->dmabuf->ops->unmap_dma_buf(attach, sg_table,
> direction);
>
> diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h
> index 0321939b1c3d..b9d0719581cd 100644
> --- a/include/linux/dma-buf.h
> +++ b/include/linux/dma-buf.h
> @@ -345,6 +345,7 @@ struct dma_buf_attachment {
> struct dma_buf *dmabuf;
> struct device *dev;
> struct list_head node;
> + struct sg_table *sgt;
> void *priv;
> };
>
> --
> 2.17.1
>
> _______________________________________________
> dri-devel mailing list
> dri-devel@xxxxxxxxxxxxxxxxxxxxx
> https://lists.freedesktop.org/mailman/listinfo/dri-devel
--
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch
_______________________________________________
dri-devel mailing list
dri-devel@xxxxxxxxxxxxxxxxxxxxx
https://lists.freedesktop.org/mailman/listinfo/dri-devel
