Hi Jason, Thomas, Christian, > If the importer provides an op for supports_interconnects(), the > exporter starts the matching (or negotiation) process (during > attach) by invoking the supports_interconnects() which would then > call this helper to identify the first common interconnect > supported by both exporter and importer. > > Note that whether an interconnect is supported between an > exporter/importer is ultimately determined by the exporter via > the match op it is expected to provide. Does this design look OK to you?
Thanks, Vivek > > Cc: Jason Gunthorpe <[email protected]> > Cc: Christian Koenig <[email protected]> > Cc: Sumit Semwal <[email protected]> > Cc: Thomas Hellström <[email protected]> > Cc: Simona Vetter <[email protected]> > Signed-off-by: Vivek Kasireddy <[email protected]> > --- > drivers/dma-buf/dma-buf.c | 45 +++++++++++++++++++++++++++- > include/linux/dma-buf-interconnect.h | 6 ++++ > include/linux/dma-buf.h | 9 ++++++ > 3 files changed, 59 insertions(+), 1 deletion(-) > > diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c > index 162642bd53e8..ed48540d1c1d 100644 > --- a/drivers/dma-buf/dma-buf.c > +++ b/drivers/dma-buf/dma-buf.c > @@ -965,8 +965,11 @@ dma_buf_dynamic_attach(struct dma_buf *dmabuf, > struct device *dev, > > attach->dev = dev; > attach->dmabuf = dmabuf; > - if (importer_ops) > + if (importer_ops) { > attach->peer2peer = importer_ops->allow_peer2peer; > + if (importer_ops->supports_interconnects) > + attach->allow_ic = true; > + } > attach->importer_ops = importer_ops; > attach->importer_priv = importer_priv; > > @@ -1680,6 +1683,46 @@ void dma_buf_unmap_interconnect(struct > dma_buf_attachment *attach, > } > EXPORT_SYMBOL_NS_GPL(dma_buf_unmap_interconnect, "DMA_BUF"); > > +bool dma_buf_match_interconnects(struct dma_buf_attachment *attach, > + const struct dma_buf_interconnect_match > *exp, > + unsigned int exp_ics, > + const struct dma_buf_interconnect_match > *imp, > + unsigned int imp_ics) > +{ > + const struct dma_buf_interconnect *exp_ic, *imp_ic; > + const struct dma_buf_interconnect_ops *ic_ops; > + struct dma_buf *dmabuf = attach->dmabuf; > + unsigned int i, j; > + > + if (!exp || !imp) > + return false; > + > + if (!attach->allow_ic) > + return false; > + > + ic_ops = dmabuf->ops->interconnect_ops; > + if (!ic_ops || !ic_ops->match_interconnect) > + return false; > + > + for (i = 0; i < exp_ics; i++) { > + for (j = 0; j < imp_ics; j++) { > + exp_ic = exp[i].interconnect; > + imp_ic = imp[j].interconnect; > + > + if (exp_ic->type == imp_ic->type) { > + if (ic_ops->match_interconnect(exp_ic, imp_ic)) > { > + attach->interconnect.type = exp_ic- > >type; > + return true; > + } > + } > + } > + } > + > + attach->allow_ic = false; > + return false; > +} > +EXPORT_SYMBOL_NS_GPL(dma_buf_match_interconnects, "DMA_BUF"); > + > #ifdef CONFIG_DEBUG_FS > static int dma_buf_debug_show(struct seq_file *s, void *unused) > { > diff --git a/include/linux/dma-buf-interconnect.h b/include/linux/dma-buf- > interconnect.h > index 17504dea9691..a72f65ed4806 100644 > --- a/include/linux/dma-buf-interconnect.h > +++ b/include/linux/dma-buf-interconnect.h > @@ -20,10 +20,16 @@ struct dma_buf_interconnect { > enum dma_buf_interconnect_type type; > }; > > +struct dma_buf_interconnect_match { > + const struct dma_buf_interconnect *interconnect; > +}; > + > struct dma_buf_interconnect_ops { > int (*map_interconnect)(struct dma_buf_attachment *attach, > struct dma_buf_ranges *ranges); > void (*unmap_interconnect)(struct dma_buf_attachment *attach, > struct dma_buf_ranges *ranges); > + bool (*match_interconnect)(const struct dma_buf_interconnect > *exp_ic, > + const struct dma_buf_interconnect *imp_ic); > }; > #endif > diff --git a/include/linux/dma-buf.h b/include/linux/dma-buf.h > index db91c67c00d6..3e6124387f3c 100644 > --- a/include/linux/dma-buf.h > +++ b/include/linux/dma-buf.h > @@ -479,6 +479,10 @@ struct dma_buf_attach_ops { > * point to the new location of the DMA-buf. > */ > void (*move_notify)(struct dma_buf_attachment *attach); > + > + bool (*supports_interconnects)(struct dma_buf_attachment *attach, > + const struct dma_buf_interconnect_match > *, > + unsigned int num_ics); > }; > > /** > @@ -599,6 +603,11 @@ void dma_buf_unmap_attachment(struct > dma_buf_attachment *, struct sg_table *, > struct dma_buf_ranges *dma_buf_map_interconnect(struct > dma_buf_attachment *); > void dma_buf_unmap_interconnect(struct dma_buf_attachment *, > struct dma_buf_ranges *); > +bool dma_buf_match_interconnects(struct dma_buf_attachment *attach, > + const struct dma_buf_interconnect_match *, > + unsigned int exp_ics, > + const struct dma_buf_interconnect_match *, > + unsigned int imp_ics); > > void dma_buf_move_notify(struct dma_buf *dma_buf); > int dma_buf_begin_cpu_access(struct dma_buf *dma_buf, > -- > 2.50.1
