On Wed, Apr 17, 2019 at 09:13:22PM +0200, Christian König wrote: > Am 17.04.19 um 21:07 schrieb Daniel Vetter: > > On Tue, Apr 16, 2019 at 08:38:33PM +0200, Christian König wrote: > > > Each importer can now provide an invalidate_mappings callback. > > > > > > This allows the exporter to provide the mappings without the need to pin > > > the backing store. > > > > > > v2: don't try to invalidate mappings when the callback is NULL, > > > lock the reservation obj while using the attachments, > > > add helper to set the callback > > > v3: move flag for invalidation support into the DMA-buf, > > > use new attach_info structure to set the callback > > > v4: use importer_priv field instead of mangling exporter priv. > > > v5: drop invalidation_supported flag > > > > > > Signed-off-by: Christian König <christian.koenig@xxxxxxx> > > > --- > > > drivers/dma-buf/dma-buf.c | 37 +++++++++++++++++++++++++++++++++++++ > > > include/linux/dma-buf.h | 33 +++++++++++++++++++++++++++++++-- > > > 2 files changed, 68 insertions(+), 2 deletions(-) > > > > > > diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c > > > index 83c92bfd964c..a3738fab3927 100644 > > > --- a/drivers/dma-buf/dma-buf.c > > > +++ b/drivers/dma-buf/dma-buf.c > > > @@ -563,6 +563,8 @@ struct dma_buf_attachment *dma_buf_attach(const struct dma_buf_attach_info *info > > > attach->dev = info->dev; > > > attach->dmabuf = dmabuf; > > > + attach->importer_priv = info->importer_priv; > > > + attach->invalidate = info->invalidate; > > > mutex_lock(&dmabuf->lock); > > > @@ -571,7 +573,9 @@ struct dma_buf_attachment *dma_buf_attach(const struct dma_buf_attach_info *info > > > if (ret) > > > goto err_attach; > > > } > > > + reservation_object_lock(dmabuf->resv, NULL); > > > list_add(&attach->node, &dmabuf->attachments); > > > + reservation_object_unlock(dmabuf->resv); > > > mutex_unlock(&dmabuf->lock); > > > @@ -615,7 +619,9 @@ void dma_buf_detach(struct dma_buf *dmabuf, struct dma_buf_attachment *attach) > > > DMA_BIDIRECTIONAL); > > > mutex_lock(&dmabuf->lock); > > > + reservation_object_lock(dmabuf->resv, NULL); > > > list_del(&attach->node); > > > + reservation_object_unlock(dmabuf->resv); > > > if (dmabuf->ops->detach) > > > dmabuf->ops->detach(dmabuf, attach); > > > @@ -653,7 +659,16 @@ dma_buf_map_attachment_locked(struct dma_buf_attachment *attach, > > > if (attach->sgt) > > > return attach->sgt; > > > + /* > > > + * Mapping a DMA-buf can trigger its invalidation, prevent sending this > > > + * event to the caller by temporary removing this attachment from the > > > + * list. > > > + */ > > > + if (attach->invalidate) > > > + list_del(&attach->node); > > Just noticed this: Why do we need this? invalidate needs the reservation > > lock, as does map_attachment. It should be impssoble to have someone else > > sneak in here. > > I was having problems with self triggered invalidations. > > E.g. client A tries to map an attachment, that in turn causes the buffer to > move to a new place and client A is informed about that movement with an > invalidation. Uh, that sounds like a bug in ttm or somewhere else in the exporter. If you evict the bo that you're trying to map, that's bad. Or maybe it's a framework bug, and we need to track whether an attachment has a map or not. That would make more sense ... -Daniel -- Daniel Vetter Software Engineer, Intel Corporation http://blog.ffwll.ch
