Re: [PATCH v2 0/6] drm: consolidate self-imported PRIME dma-buf detection

[Matthew Brost <matthew.brost@intel.com>]

On Mon, Oct 12, 2026 at 06:06:12PM -0700, Niranjana Vishwanathapura wrote:
> Detecting that a PRIME dma-buf being imported was exported by the same
> DRM device is a pattern currently open-coded in many drivers (compare
> dma_buf->ops against the driver's own ops, check obj->dev == dev, then
> return the GEM object with an extra reference). This series adds generic
> helpers for it and converts several drivers to use them.
> 
> Patch 1 adds drm_gem_prime_self_import(dev, dma_buf, ops): for a dma-buf
> self-exported via the given ops, it returns the backing GEM object with
> a reference, letting a driver short-circuit the generic PRIME import and
> skip the extra dma-buf file reference. Patch 2 converts Xe to it.
> 
> Patch 3 adds drm_gem_prime_dma_buf_to_gem(), a thin wrapper that uses the
> core PRIME ops, and replaces the drm_gem_is_prime_exported_dma_buf() bool
> predicate with it so the shmem importer resolves the object directly
> (the sole caller already wanted the referenced object).
> 
> Patches 4-6 convert panthor, panfrost and amdgpu to
> drm_gem_prime_self_import(), removing the duplicated open-coded checks.
> 
> No intended functional change.
> 
> Assisted-by: GitHub-Copilot:claude-opus-4.8
> Signed-off-by: Niranjana Vishwanathapura <niranjana.vishwanathapura@intel.com>
> 
> Farah Kassabri (2):
>   drm/gem: add helper to detect self-imported PRIME dma-bufs
>   drm/xe/dma-buf: Use drm helper to detect dma-buf self-import
> 
> Niranjana Vishwanathapura (4):
>   drm/gem: add drm_gem_prime_dma_buf_to_gem() self-import helper

For the other driver patches:

Acked-by: Matthew Brost <matthew.brost@intel.com>

I'll leave the RB's to individual maintainers.

>   drm/panthor: use drm_gem_prime_self_import() helper
>   drm/panfrost: use drm_gem_prime_self_import() helper
>   drm/amdgpu: use drm_gem_prime_self_import() helper
> 
>  drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c | 14 +---
>  drivers/gpu/drm/drm_gem_shmem_helper.c      | 14 ++--
>  drivers/gpu/drm/drm_prime.c                 | 74 +++++++++++++++------
>  drivers/gpu/drm/panfrost/panfrost_gem.c     | 10 +--
>  drivers/gpu/drm/panthor/panthor_gem.c       | 10 +--
>  drivers/gpu/drm/xe/xe_dma_buf.c             | 23 ++++---
>  drivers/gpu/drm/xe/xe_dma_buf.h             |  2 +
>  include/drm/drm_prime.h                     |  8 ++-
>  8 files changed, 91 insertions(+), 64 deletions(-)
> 
> -- 
> 2.43.0
>