On Thu, May 14, 2020 at 11:08:52AM +0900, David Stevens wrote:

On Thu, May 14, 2020 at 12:45 AM Daniel Vetter [off-list ref] wrote:

quoted

On Wed, Mar 11, 2020 at 12:20 PM David Stevens [off-list ref] wrote:

quoted

This change adds a new dma-buf operation that allows dma-bufs to be used
by virtio drivers to share exported objects. The new operation allows
the importing driver to query the exporting driver for the UUID which
identifies the underlying exported object.

Signed-off-by: David Stevens <redacted>

Adding Tomasz Figa, I've discussed this with him at elce last year I
think. Just to make sure.

Bunch of things:
- obviously we need the users of this in a few drivers, can't really
review anything stand-alone

Here is a link to the usage of this feature by the currently under
development virtio-video driver:
https://markmail.org/thread/j4xlqaaim266qpks

quoted

- adding very specific ops to the generic interface is rather awkward,
eventually everyone wants that and we end up in a mess. I think the
best solution here would be if we create a struct virtio_dma_buf which
subclasses dma-buf, add a (hopefully safe) runtime upcasting
functions, and then a virtio_dma_buf_get_uuid() function. Just storing
the uuid should be doable (assuming this doesn't change during the
lifetime of the buffer), so no need for a callback.

So you would prefer a solution similar to the original version of this
patchset? https://markmail.org/message/z7if4u56q5fmaok4

yup.
-Daniel
-- 
Daniel Vetter
Software Engineer, Intel Corporation
http://blog.ffwll.ch