On Thu, Sep 27, 2018 at 08:47:33AM -0700, Christoph Hellwig wrote: > > +static void *csky_dma_alloc_atomic( > > + struct device *dev, > > + size_t size, > > + dma_addr_t *dma_handle > > + ) > > Can you please use normal kernel coding style? Closing brace on the > same line, either two tab indents for the arguments or align them to the > first argument: > > static void *csky_dma_alloc_atomic(struct device *dev, size_t size, > dma_addr_t *dma_handle) > > or: > > static void *csky_dma_alloc_atomic(struct device *dev, size_t size, > dma_addr_t *dma_handle) Ok. > > > + if (DMA_ATTR_NON_CONSISTENT & attrs) > > + BUG(); > > Please don't bug on unknown attributs, they can be safely ignored. Ok. > > > +void arch_sync_dma_for_device(struct device *dev, phys_addr_t paddr, > > + size_t size, enum dma_data_direction dir) > > +{ > > + struct page *page = pfn_to_page(paddr >> PAGE_SHIFT); > > + unsigned long offset = paddr & ~PAGE_MASK; > > + unsigned long vaddr; > > + > > + if (PageHighMem(page)) > > + vaddr = (unsigned long) kmap_atomic(page); > > This isn't going to work as the size might be larger than PAGE_SIZE. Yes, you are right. I must fix it up. Thank you Best Regards Guo Ren