456 void sg_miter_start(struct sg_mapping_iter *miter, struct scatterlist *sgl,  in sg_miter_start()  argument
459 	memset(miter, 0, sizeof(struct sg_mapping_iter));  in sg_miter_start()
461 	__sg_page_iter_start(&miter->piter, sgl, nents, 0);  in sg_miter_start()
463 	miter->__flags = flags;  in sg_miter_start()
467 static bool sg_miter_get_next_page(struct sg_mapping_iter *miter)  in sg_miter_get_next_page()  argument
469 	if (!miter->__remaining) {  in sg_miter_get_next_page()
473 		if (!__sg_page_iter_next(&miter->piter))  in sg_miter_get_next_page()
476 		sg = miter->piter.sg;  in sg_miter_get_next_page()
477 		pgoffset = miter->piter.sg_pgoffset;  in sg_miter_get_next_page()
479 		miter->__offset = pgoffset ? 0 : sg->offset;  in sg_miter_get_next_page()
480 		miter->__remaining = sg->offset + sg->length -  in sg_miter_get_next_page()
481 				(pgoffset << PAGE_SHIFT) - miter->__offset;  in sg_miter_get_next_page()
482 		miter->__remaining = min_t(unsigned long, miter->__remaining,  in sg_miter_get_next_page()
483 					   PAGE_SIZE - miter->__offset);  in sg_miter_get_next_page()
507 bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset)  in sg_miter_skip()  argument
509 	sg_miter_stop(miter);  in sg_miter_skip()
514 		if (!sg_miter_get_next_page(miter))  in sg_miter_skip()
517 		consumed = min_t(off_t, offset, miter->__remaining);  in sg_miter_skip()
518 		miter->__offset += consumed;  in sg_miter_skip()
519 		miter->__remaining -= consumed;  in sg_miter_skip()
544 bool sg_miter_next(struct sg_mapping_iter *miter)  in sg_miter_next()  argument
546 	sg_miter_stop(miter);  in sg_miter_next()
552 	if (!sg_miter_get_next_page(miter))  in sg_miter_next()
555 	miter->page = sg_page_iter_page(&miter->piter);  in sg_miter_next()
556 	miter->consumed = miter->length = miter->__remaining;  in sg_miter_next()
558 	if (miter->__flags & SG_MITER_ATOMIC)  in sg_miter_next()
559 		miter->addr = kmap_atomic(miter->page) + miter->__offset;  in sg_miter_next()
561 		miter->addr = kmap(miter->page) + miter->__offset;  in sg_miter_next()
581 void sg_miter_stop(struct sg_mapping_iter *miter)  in sg_miter_stop()  argument
583 	WARN_ON(miter->consumed > miter->length);  in sg_miter_stop()
586 	if (miter->addr) {  in sg_miter_stop()
587 		miter->__offset += miter->consumed;  in sg_miter_stop()
588 		miter->__remaining -= miter->consumed;  in sg_miter_stop()
590 		if ((miter->__flags & SG_MITER_TO_SG) &&  in sg_miter_stop()
591 		    !PageSlab(miter->page))  in sg_miter_stop()
592 			flush_kernel_dcache_page(miter->page);  in sg_miter_stop()
594 		if (miter->__flags & SG_MITER_ATOMIC) {  in sg_miter_stop()
596 			kunmap_atomic(miter->addr);  in sg_miter_stop()
598 			kunmap(miter->page);  in sg_miter_stop()
600 		miter->page = NULL;  in sg_miter_stop()
601 		miter->addr = NULL;  in sg_miter_stop()
602 		miter->length = 0;  in sg_miter_stop()
603 		miter->consumed = 0;  in sg_miter_stop()
626 	struct sg_mapping_iter miter;  in sg_copy_buffer()  local
635 	sg_miter_start(&miter, sgl, nents, sg_flags);  in sg_copy_buffer()
637 	if (!sg_miter_skip(&miter, skip))  in sg_copy_buffer()
642 	while (sg_miter_next(&miter) && offset < buflen) {  in sg_copy_buffer()
645 		len = min(miter.length, buflen - offset);  in sg_copy_buffer()
648 			memcpy(buf + offset, miter.addr, len);  in sg_copy_buffer()
650 			memcpy(miter.addr, buf + offset, len);  in sg_copy_buffer()
655 	sg_miter_stop(&miter);  in sg_copy_buffer()