linux-master/lib/scatterlist.c

725 void __sg_page_iter_start(struct sg_page_iter *piter,
729 	piter->__pg_advance = 0;
730 	piter->__nents = nents;
732 	piter->sg = sglist;
733 	piter->sg_pgoffset = pgoffset;
742 bool __sg_page_iter_next(struct sg_page_iter *piter)
744 	if (!piter->__nents || !piter->sg)
747 	piter->sg_pgoffset += piter->__pg_advance;
748 	piter->__pg_advance = 1;
750 	while (piter->sg_pgoffset >= sg_page_count(piter->sg)) {
751 		piter->sg_pgoffset -= sg_page_count(piter->sg);
752 		piter->sg = sg_next(piter->sg);
753 		if (!--piter->__nents || !piter->sg)
768 	struct sg_page_iter *piter = &dma_iter->base;
770 	if (!piter->__nents || !piter->sg)
773 	piter->sg_pgoffset += piter->__pg_advance;
774 	piter->__pg_advance = 1;
776 	while (piter->sg_pgoffset >= sg_dma_page_count(piter->sg)) {
777 		piter->sg_pgoffset -= sg_dma_page_count(piter->sg);
778 		piter->sg = sg_next(piter->sg);
779 		if (!--piter->__nents || !piter->sg)
805 	__sg_page_iter_start(&miter->piter, sgl, nents, 0);
816 		if (!__sg_page_iter_next(&miter->piter))
819 		sg = miter->piter.sg;
821 		miter->__offset = miter->piter.sg_pgoffset ? 0 : sg->offset;
822 		miter->piter.sg_pgoffset += miter->__offset >> PAGE_SHIFT;
825 				     (miter->piter.sg_pgoffset << PAGE_SHIFT) -
898 	miter->page = sg_page_iter_page(&miter->piter);