484 void sg_miter_start(struct sg_mapping_iter *miter, struct scatterlist *sgl,  in sg_miter_start()  argument
487 	memset(miter, 0, sizeof(struct sg_mapping_iter));  in sg_miter_start()
489 	__sg_page_iter_start(&miter->piter, sgl, nents, 0);  in sg_miter_start()
491 	miter->__flags = flags;  in sg_miter_start()
495 static bool sg_miter_get_next_page(struct sg_mapping_iter *miter)  in sg_miter_get_next_page()  argument
497 	if (!miter->__remaining) {  in sg_miter_get_next_page()
501 		if (!__sg_page_iter_next(&miter->piter))  in sg_miter_get_next_page()
504 		sg = miter->piter.sg;  in sg_miter_get_next_page()
505 		pgoffset = miter->piter.sg_pgoffset;  in sg_miter_get_next_page()
507 		miter->__offset = pgoffset ? 0 : sg->offset;  in sg_miter_get_next_page()
508 		miter->__remaining = sg->offset + sg->length -  in sg_miter_get_next_page()
509 				(pgoffset << PAGE_SHIFT) - miter->__offset;  in sg_miter_get_next_page()
510 		miter->__remaining = min_t(unsigned long, miter->__remaining,  in sg_miter_get_next_page()
511 					   PAGE_SIZE - miter->__offset);  in sg_miter_get_next_page()
535 bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset)  in sg_miter_skip()  argument
537 	sg_miter_stop(miter);  in sg_miter_skip()
542 		if (!sg_miter_get_next_page(miter))  in sg_miter_skip()
545 		consumed = min_t(off_t, offset, miter->__remaining);  in sg_miter_skip()
546 		miter->__offset += consumed;  in sg_miter_skip()
547 		miter->__remaining -= consumed;  in sg_miter_skip()
572 bool sg_miter_next(struct sg_mapping_iter *miter)  in sg_miter_next()  argument
574 	sg_miter_stop(miter);  in sg_miter_next()
580 	if (!sg_miter_get_next_page(miter))  in sg_miter_next()
583 	miter->page = sg_page_iter_page(&miter->piter);  in sg_miter_next()
584 	miter->consumed = miter->length = miter->__remaining;  in sg_miter_next()
586 	if (miter->__flags & SG_MITER_ATOMIC)  in sg_miter_next()
587 		miter->addr = kmap_atomic(miter->page) + miter->__offset;  in sg_miter_next()
589 		miter->addr = kmap(miter->page) + miter->__offset;  in sg_miter_next()
609 void sg_miter_stop(struct sg_mapping_iter *miter)  in sg_miter_stop()  argument
611 	WARN_ON(miter->consumed > miter->length);  in sg_miter_stop()
614 	if (miter->addr) {  in sg_miter_stop()
615 		miter->__offset += miter->consumed;  in sg_miter_stop()
616 		miter->__remaining -= miter->consumed;  in sg_miter_stop()
618 		if ((miter->__flags & SG_MITER_TO_SG) &&  in sg_miter_stop()
619 		    !PageSlab(miter->page))  in sg_miter_stop()
620 			flush_kernel_dcache_page(miter->page);  in sg_miter_stop()
622 		if (miter->__flags & SG_MITER_ATOMIC) {  in sg_miter_stop()
624 			kunmap_atomic(miter->addr);  in sg_miter_stop()
626 			kunmap(miter->page);  in sg_miter_stop()
628 		miter->page = NULL;  in sg_miter_stop()
629 		miter->addr = NULL;  in sg_miter_stop()
630 		miter->length = 0;  in sg_miter_stop()
631 		miter->consumed = 0;  in sg_miter_stop()
653 	struct sg_mapping_iter miter;  in sg_copy_buffer()  local
662 	sg_miter_start(&miter, sgl, nents, sg_flags);  in sg_copy_buffer()
664 	if (!sg_miter_skip(&miter, skip))  in sg_copy_buffer()
669 	while (sg_miter_next(&miter) && offset < buflen) {  in sg_copy_buffer()
672 		len = min(miter.length, buflen - offset);  in sg_copy_buffer()
675 			memcpy(buf + offset, miter.addr, len);  in sg_copy_buffer()
677 			memcpy(miter.addr, buf + offset, len);  in sg_copy_buffer()
682 	sg_miter_stop(&miter);  in sg_copy_buffer()