[Linaro-mm-sig] Re: [PATCH v3 2/7] dma-buf: Always build with DMABUF_MOVE_NOTIFY

On Wed, Jan 21, 2026 at 09:55:38AM +0100, Christian König wrote:

On 1/20/26 15:07, Leon Romanovsky wrote:

...

From: Leon Romanovsky leonro@nvidia.com

DMABUF_MOVE_NOTIFY was introduced in 2018 and has been marked as experimental and disabled by default ever since. Six years later, all new importers implement this callback.

It is therefore reasonable to drop CONFIG_DMABUF_MOVE_NOTIFY and always build DMABUF with support for it enabled.

Suggested-by: Christian König christian.koenig@amd.com Signed-off-by: Leon Romanovsky leonro@nvidia.com

---

drivers/dma-buf/Kconfig | 12 ------------ drivers/dma-buf/dma-buf.c | 12 ++---------- drivers/gpu/drm/amd/amdgpu/amdgpu_dma_buf.c | 10 +++------- drivers/gpu/drm/amd/amdkfd/Kconfig | 2 +- drivers/gpu/drm/xe/tests/xe_dma_buf.c | 3 +-- drivers/gpu/drm/xe/xe_dma_buf.c | 12 ++++-------- 6 files changed, 11 insertions(+), 40 deletions(-)

diff --git a/drivers/dma-buf/Kconfig b/drivers/dma-buf/Kconfig index b46eb8a552d7..84d5e9b24e20 100644 --- a/drivers/dma-buf/Kconfig +++ b/drivers/dma-buf/Kconfig @@ -40,18 +40,6 @@ config UDMABUF A driver to let userspace turn memfd regions into dma-bufs. Qemu can use this to create host dmabufs for guest framebuffers. -config DMABUF_MOVE_NOTIFY

• bool "Move notify between drivers (EXPERIMENTAL)"
• default n
• depends on DMA_SHARED_BUFFER
• help

•  Don't pin buffers if the dynamic DMA-buf interface is available on
  

•  both the exporter as well as the importer. This fixes a security
  

•  problem where userspace is able to pin unrestricted amounts of memory
  

•  through DMA-buf.
  

•  This is marked experimental because we don't yet have a consistent
  

•  execution context and memory management between drivers.
  

config DMABUF_DEBUG bool "DMA-BUF debug checks" depends on DMA_SHARED_BUFFER diff --git a/drivers/dma-buf/dma-buf.c b/drivers/dma-buf/dma-buf.c index 59cc647bf40e..cd3b60ce4863 100644 --- a/drivers/dma-buf/dma-buf.c +++ b/drivers/dma-buf/dma-buf.c @@ -837,18 +837,10 @@ static void mangle_sg_table(struct sg_table *sg_table) } -static inline bool -dma_buf_attachment_is_dynamic(struct dma_buf_attachment *attach)

I would rather like to keep the wrapper and even add some explanation what it means when true is returned.

We have different opinion here. I don't like single line functions which are called only twice. I'll keep this function to ensure progress the series.

Thanks

Apart from that looks good to me.

Regards, Christian.