It looks like it could be nice to define and use a helper for
page_address(sg_page(sg)) (although 11 call sites could use it
after this patch)
#define sg_pgaddr(sg) page_address(sg_page(sg))
Note that mips sg_{un,}map_sg checked for page_address(sg->page) != 0
before calling __dma_sync(addr + sg->offset, sg->length, direction)
and you changed it to addr = (unsigned long) sg_virt(sg) which
takes sg->offset into account. That said I'm not sure if the original
code was correct for the (page_address(sg->page) == 0 && sg->offset != 0)
case...
On Oct. 22, 2007, 20:11 +0200, Jens Axboe <[email protected]> wrote:
<snip>
> diff --git a/arch/mips/mm/dma-default.c b/arch/mips/mm/dma-default.c
> index 98b5e5b..b0b034c 100644
> --- a/arch/mips/mm/dma-default.c
> +++ b/arch/mips/mm/dma-default.c
> @@ -165,12 +165,11 @@ int dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
> for (i = 0; i < nents; i++, sg++) {
> unsigned long addr;
>
> - addr = (unsigned long) page_address(sg->page);
> + addr = (unsigned long) sg_virt(sg);
> if (!plat_device_is_coherent(dev) && addr)
> - __dma_sync(addr + sg->offset, sg->length, direction);
> + __dma_sync(addr, sg->length, direction);
> sg->dma_address = plat_map_dma_mem(dev,
> - (void *)(addr + sg->offset),
> - sg->length);
> + (void *)addr, sg->length);
> }
>
> return nents;
> @@ -223,10 +222,9 @@ void dma_unmap_sg(struct device *dev, struct scatterlist *sg, int nhwentries,
> for (i = 0; i < nhwentries; i++, sg++) {
> if (!plat_device_is_coherent(dev) &&
> direction != DMA_TO_DEVICE) {
> - addr = (unsigned long) page_address(sg->page);
> + addr = (unsigned long) sg_virt(sg);
> if (addr)
> - __dma_sync(addr + sg->offset, sg->length,
> - direction);
> + __dma_sync(addr, sg->length, direction);
> }
> plat_unmap_dma_mem(sg->dma_address);
> }
<snip>
> diff --git a/arch/x86/kernel/pci-calgary_64.c b/arch/x86/kernel/pci-calgary_64.c
> index 5098f58..1a20fe3 100644
> --- a/arch/x86/kernel/pci-calgary_64.c
> +++ b/arch/x86/kernel/pci-calgary_64.c
> @@ -411,8 +411,10 @@ static int calgary_nontranslate_map_sg(struct device* dev,
> int i;
>
> for_each_sg(sg, s, nelems, i) {
> - BUG_ON(!s->page);
> - s->dma_address = virt_to_bus(page_address(s->page) +s->offset);
> + struct page *p = sg_page(s);
> +
> + BUG_ON(!p);
why not just BUG_ON(!sg_page(s))?
> + s->dma_address = virt_to_bus(sg_virt(s));
> s->dma_length = s->length;
> }
> return nelems;
-
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