Re: [PATCH v8 0/2] dma-buf: Fix silent overflow and alignment

[Leon Romanovsky]

On Wed, Sep 02, 2026 at 09:00:46AM +0200, Christian König wrote:
> On 9/1/26 19:08, David Hu wrote:
> > From: David Hu <xuehaohu@xxxxxxxxxx>
> > 
> > This series address two related issues in scatter-gather mapping,
> > specifically for the MMIO based dma-buf mapping. The fixes ensure
> > sgt mapping is correct, and proper for large MMIO regions.
> > 
> > Patch 1 fixes a silent integer overflow for mapping length exceeding 4G
> > (Previously submitted as [PATCH v7] dma-buf: Fix silent overflow for
> > phys vec to sgt)
> > https://lore.kernel.org/all/20260609164047.486227-1-xuehaohu@xxxxxxxxxx/
> > 
> > Patch 2 Splits sgl by largest page aligned chunk
> > (Previously submitted as [PATCH v3] dma-buf: Split sgl by largest page-aligned chunk)
> > https://lore.kernel.org/all/20260722233806.3922093-1-dhu@xxxxxx/
> 
> *sigh* such issues are exactly the reason why I didn't wanted the dma-mapping stuff inside DMA-buf. That clearly doesn't belong here.

And this is why so many in the kernel community want to get rid of SG
lists. It would be great if DMA-BUF could also eliminate the need to
convert to an SGL, like Jason proposed.

The DMA layer no longer needs SGL. These bugs belong to the DMA-BUF layer,
which is the one that depends on it.

Thanks