On Thu, May 14, 2020 at 11:08:52AM +0900, David Stevens wrote:
On Thu, May 14, 2020 at 12:45 AM Daniel Vetter daniel@ffwll.ch wrote:
On Wed, Mar 11, 2020 at 12:20 PM David Stevens stevensd@chromium.org wrote:
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 stevensd@chromium.org
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
- 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