On Fri, Feb 26, 2021 at 5:09 AM John Stultz john.stultz@linaro.org wrote:

Per discussion and patches here: https://lore.kernel.org/dri-devel/20210223105951.912577-1-daniel.vetter@ffwl...

Daniel is planning on making VM_PFNMAP required on dmabufs.

Thus to avoid the warn_on noise, set the VM_PFNMAP in the system and cma heap's mmap handler.

Cc: Daniel Vetter daniel@ffwll.ch Cc: Jason Gunthorpe jgg@ziepe.ca Cc: Christian Koenig christian.koenig@amd.com Cc: Sumit Semwal sumit.semwal@linaro.org Cc: Liam Mark lmark@codeaurora.org Cc: Chris Goldsworthy cgoldswo@codeaurora.org Cc: Laura Abbott labbott@kernel.org Cc: Brian Starkey Brian.Starkey@arm.com Cc: Hridya Valsaraju hridya@google.com Cc: Suren Baghdasaryan surenb@google.com Cc: Sandeep Patil sspatil@google.com Cc: Daniel Mentz danielmentz@google.com Cc: Ørjan Eide orjan.eide@arm.com Cc: Robin Murphy robin.murphy@arm.com Cc: Ezequiel Garcia ezequiel@collabora.com Cc: Simon Ser contact@emersion.fr Cc: James Jones jajones@nvidia.com Cc: linux-media@vger.kernel.org Cc: dri-devel@lists.freedesktop.org Signed-off-by: John Stultz john.stultz@linaro.org

System heap uses remap_pfn_range so looks fine, but cma heap inserts pages, and that's not fine for VM_PFNMAP. You need to use vm_insert_pfn or remap_pfn_range or one of the related pfn mapping functions for that too. I think this should splat when you run it.

Also note that remap_pfn_range updates the vma flags already correctly for you, so you probably don't want to do that.

Also given that both deal with struct page there's a ton of divergence between these two that doesn't make much sense. Maybe could even share the code fully, aside from how you allocate the struct pages. -Daniel

---

drivers/dma-buf/heaps/cma_heap.c | 1 + drivers/dma-buf/heaps/system_heap.c | 4 +++- 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/dma-buf/heaps/cma_heap.c b/drivers/dma-buf/heaps/cma_heap.c index 364fc2f3e499..34bc3987f942 100644 --- a/drivers/dma-buf/heaps/cma_heap.c +++ b/drivers/dma-buf/heaps/cma_heap.c @@ -185,6 +185,7 @@ static int cma_heap_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma)

    vma->vm_ops = &dma_heap_vm_ops;
    vma->vm_private_data = buffer;

•   vma->vm_flags |= VM_PFNMAP;
  
    return 0;
  

} diff --git a/drivers/dma-buf/heaps/system_heap.c b/drivers/dma-buf/heaps/system_heap.c index 3548b20cb98c..8995e3cbfcaf 100644 --- a/drivers/dma-buf/heaps/system_heap.c +++ b/drivers/dma-buf/heaps/system_heap.c @@ -228,8 +228,10 @@ static int system_heap_mmap(struct dma_buf *dmabuf, struct vm_area_struct *vma) return ret; addr += PAGE_SIZE; if (addr >= vma->vm_end)

•                   return 0;
  

•                   break;
    }
  

•   vma->vm_flags |= VM_PFNMAP;
    return 0;
  

}

-- 2.25.1