On 10/30/25 15:05, Boris Brezillon wrote: > drm_gem_is_prime_exported_dma_buf() checks the dma_buf->ops against > drm_gem_prime_dmabuf_ops, which makes it impossible to use if the > driver implements custom dma_buf_ops. Instead of duplicating a bunch > of helpers to work around it, let's provide a way for drivers to > expose their custom dma_buf_ops so the core prime helpers can rely on > that instead of hardcoding &drm_gem_prime_dmabuf_ops.
That's generally nice to have, I've re-implemented quite a number of functions in amdgpu because of this as well. > > v5: > - New patch > > Signed-off-by: Boris Brezillon <[email protected]> > --- > drivers/gpu/drm/drm_prime.c | 14 +++++++++++--- > include/drm/drm_drv.h | 8 ++++++++ > 2 files changed, 19 insertions(+), 3 deletions(-) > > diff --git a/drivers/gpu/drm/drm_prime.c b/drivers/gpu/drm/drm_prime.c > index 43a10b4af43a..3796844af418 100644 > --- a/drivers/gpu/drm/drm_prime.c > +++ b/drivers/gpu/drm/drm_prime.c > @@ -903,6 +903,15 @@ unsigned long drm_prime_get_contiguous_size(struct > sg_table *sgt) > } > EXPORT_SYMBOL(drm_prime_get_contiguous_size); > > +static const struct dma_buf_ops * > +drm_gem_prime_get_dma_buf_ops(struct drm_device *dev) > +{ > + if (dev->driver->gem_prime_get_dma_buf_ops) > + return dev->driver->gem_prime_get_dma_buf_ops(dev); I have strong doubts that a driver changes their dma_buf ops during their runtime, so instead of a callback could we just have it as pointer in drm_driver? Regards, Christian. > + > + return &drm_gem_prime_dmabuf_ops; > +} > + > /** > * drm_gem_prime_export - helper library implementation of the export > callback > * @obj: GEM object to export > @@ -919,7 +928,7 @@ struct dma_buf *drm_gem_prime_export(struct > drm_gem_object *obj, > struct dma_buf_export_info exp_info = { > .exp_name = KBUILD_MODNAME, /* white lie for debug */ > .owner = dev->driver->fops->owner, > - .ops = &drm_gem_prime_dmabuf_ops, > + .ops = drm_gem_prime_get_dma_buf_ops(dev), > .size = obj->size, > .flags = flags, > .priv = obj, > @@ -930,7 +939,6 @@ struct dma_buf *drm_gem_prime_export(struct > drm_gem_object *obj, > } > EXPORT_SYMBOL(drm_gem_prime_export); > > - > /** > * drm_gem_is_prime_exported_dma_buf - > * checks if the DMA-BUF was exported from a GEM object belonging to @dev. > @@ -946,7 +954,7 @@ bool drm_gem_is_prime_exported_dma_buf(struct drm_device > *dev, > { > struct drm_gem_object *obj = dma_buf->priv; > > - return (dma_buf->ops == &drm_gem_prime_dmabuf_ops) && (obj->dev == dev); > + return (dma_buf->ops == drm_gem_prime_get_dma_buf_ops(dev)) && > (obj->dev == dev); > } > EXPORT_SYMBOL(drm_gem_is_prime_exported_dma_buf); > > diff --git a/include/drm/drm_drv.h b/include/drm/drm_drv.h > index 42fc085f986d..f18da3c0edb8 100644 > --- a/include/drm/drm_drv.h > +++ b/include/drm/drm_drv.h > @@ -326,6 +326,14 @@ struct drm_driver { > struct dma_buf_attachment *attach, > struct sg_table *sgt); > > + /** > + * @gem_prime_get_dma_buf_ops: > + * > + * Optional hook used by the PRIME helpers to get the custom dma_buf_ops > + * used by this driver. > + */ > + const struct dma_buf_ops *(*gem_prime_get_dma_buf_ops)(struct > drm_device *dev); > + > /** > * @dumb_create: > *
