Re: [PATCH v5 13/15] iommu/dma: Force bouncing if the size is not cacheline-aligned

[Catalin Marinas <catalin.marinas@arm.com>]

On Sat, May 27, 2023 at 12:36:30AM +0800, Jisheng Zhang wrote:
> On Wed, May 24, 2023 at 06:19:02PM +0100, Catalin Marinas wrote:
> > diff --git a/include/linux/scatterlist.h b/include/linux/scatterlist.h
> > index 87aaf8b5cdb4..330a157c5501 100644
> > --- a/include/linux/scatterlist.h
> > +++ b/include/linux/scatterlist.h
> > @@ -248,6 +248,29 @@ static inline void sg_unmark_end(struct scatterlist *sg)
> >  	sg->page_link &= ~SG_END;
> >  }
> >  
> > +#define SG_DMA_BUS_ADDRESS	(1 << 0)
> > +#define SG_DMA_USE_SWIOTLB	(1 << 1)
> > +
> > +#ifdef CONFIG_SWIOTLB
> 
> s/CONFIG_SWIOTLB/CONFIG_NEED_SG_DMA_FLAGS ?
> Otherwise, there's compiler error if SWIOTLB=y but IOMMU=n

Yes, I pushed a fixup to the kmalloc-minalign branch.

> > +static inline bool sg_is_dma_use_swiotlb(struct scatterlist *sg)
> > +{
> > +	return sg->dma_flags & SG_DMA_USE_SWIOTLB;
> > +}
> > +
> > +static inline void sg_dma_mark_use_swiotlb(struct scatterlist *sg)
> > +{
> > +	sg->dma_flags |= SG_DMA_USE_SWIOTLB;
> > +}
> > +#else
> > +static inline bool sg_is_dma_use_swiotlb(struct scatterlist *sg)
> > +{
> > +	return false;
> > +}
> > +static inline void sg_dma_mark_use_swiotlb(struct scatterlist *sg)
> > +{
> > +}
> > +#endif

And I wonder whether we should keep these accessors in the scatterlist.h
file. They are only used by the dma-iommu.c code.

-- 
Catalin