On Mon, Dec 24, 2018 at 04:32:22PM -0600, Shiraz Saleem wrote:
> - for_each_sg(umem->sg_head.sgl, sg, umem->nmap, entry) {
> - pages = sg_dma_len(sg) >> PAGE_SHIFT;
> - for (i = 0; i < pages; i++) {
> - paddr = sg_dma_address(sg) + (i << PAGE_SHIFT);
> - if (pbl_tbl == pbl_tbl_orig)
> - *pbl_tbl++ = paddr & ~page_mask;
> - else if ((paddr & page_mask) == 0)
> - *pbl_tbl++ = paddr;
> - }
> + struct sg_page_iter sg_iter;
> +
> + for_each_sg_page(umem->sg_head.sgl, &sg_iter, umem->nmap, 0) {
> + paddr = sg_page_iter_dma_address(&sg_iter);
Actually, I'm looking at this again, and thinking this looks
problematic..
for_each_sg_page iterates over the original SGL, it does not iterate
over the DMA mapped SGL (ie it does not use sg_dma_len()) - so this is
not an entirely equivalent transformation.
I think you need to add a for_each_sg_dma_page() to make this work
correctly? The only difference would be to use sg_dma_len instead of
length?
And I wonder how many of these places in drivers work properly if
PAGE_SIZE != 4k :(
CH: Does sg_page_iter_dma_address() even make any sense??
Jason
