674 void sg_miter_start(struct sg_mapping_iter *miter, struct scatterlist *sgl,  in sg_miter_start()  argument
677 	memset(miter, 0, sizeof(struct sg_mapping_iter));  in sg_miter_start()
679 	__sg_page_iter_start(&miter->piter, sgl, nents, 0);  in sg_miter_start()
681 	miter->__flags = flags;  in sg_miter_start()
685 static bool sg_miter_get_next_page(struct sg_mapping_iter *miter)  in sg_miter_get_next_page()  argument
687 	if (!miter->__remaining) {  in sg_miter_get_next_page()
690 		if (!__sg_page_iter_next(&miter->piter))  in sg_miter_get_next_page()
693 		sg = miter->piter.sg;  in sg_miter_get_next_page()
695 		miter->__offset = miter->piter.sg_pgoffset ? 0 : sg->offset;  in sg_miter_get_next_page()
696 		miter->piter.sg_pgoffset += miter->__offset >> PAGE_SHIFT;  in sg_miter_get_next_page()
697 		miter->__offset &= PAGE_SIZE - 1;  in sg_miter_get_next_page()
698 		miter->__remaining = sg->offset + sg->length -  in sg_miter_get_next_page()
699 				     (miter->piter.sg_pgoffset << PAGE_SHIFT) -  in sg_miter_get_next_page()
700 				     miter->__offset;  in sg_miter_get_next_page()
701 		miter->__remaining = min_t(unsigned long, miter->__remaining,  in sg_miter_get_next_page()
702 					   PAGE_SIZE - miter->__offset);  in sg_miter_get_next_page()
726 bool sg_miter_skip(struct sg_mapping_iter *miter, off_t offset)  in sg_miter_skip()  argument
728 	sg_miter_stop(miter);  in sg_miter_skip()
733 		if (!sg_miter_get_next_page(miter))  in sg_miter_skip()
736 		consumed = min_t(off_t, offset, miter->__remaining);  in sg_miter_skip()
737 		miter->__offset += consumed;  in sg_miter_skip()
738 		miter->__remaining -= consumed;  in sg_miter_skip()
763 bool sg_miter_next(struct sg_mapping_iter *miter)  in sg_miter_next()  argument
765 	sg_miter_stop(miter);  in sg_miter_next()
771 	if (!sg_miter_get_next_page(miter))  in sg_miter_next()
774 	miter->page = sg_page_iter_page(&miter->piter);  in sg_miter_next()
775 	miter->consumed = miter->length = miter->__remaining;  in sg_miter_next()
777 	if (miter->__flags & SG_MITER_ATOMIC)  in sg_miter_next()
778 		miter->addr = kmap_atomic(miter->page) + miter->__offset;  in sg_miter_next()
780 		miter->addr = kmap(miter->page) + miter->__offset;  in sg_miter_next()
800 void sg_miter_stop(struct sg_mapping_iter *miter)  in sg_miter_stop()  argument
802 	WARN_ON(miter->consumed > miter->length);  in sg_miter_stop()
805 	if (miter->addr) {  in sg_miter_stop()
806 		miter->__offset += miter->consumed;  in sg_miter_stop()
807 		miter->__remaining -= miter->consumed;  in sg_miter_stop()
809 		if ((miter->__flags & SG_MITER_TO_SG) &&  in sg_miter_stop()
810 		    !PageSlab(miter->page))  in sg_miter_stop()
811 			flush_kernel_dcache_page(miter->page);  in sg_miter_stop()
813 		if (miter->__flags & SG_MITER_ATOMIC) {  in sg_miter_stop()
815 			kunmap_atomic(miter->addr);  in sg_miter_stop()
817 			kunmap(miter->page);  in sg_miter_stop()
819 		miter->page = NULL;  in sg_miter_stop()
820 		miter->addr = NULL;  in sg_miter_stop()
821 		miter->length = 0;  in sg_miter_stop()
822 		miter->consumed = 0;  in sg_miter_stop()
844 	struct sg_mapping_iter miter;  in sg_copy_buffer()  local
852 	sg_miter_start(&miter, sgl, nents, sg_flags);  in sg_copy_buffer()
854 	if (!sg_miter_skip(&miter, skip))  in sg_copy_buffer()
857 	while ((offset < buflen) && sg_miter_next(&miter)) {  in sg_copy_buffer()
860 		len = min(miter.length, buflen - offset);  in sg_copy_buffer()
863 			memcpy(buf + offset, miter.addr, len);  in sg_copy_buffer()
865 			memcpy(miter.addr, buf + offset, len);  in sg_copy_buffer()
870 	sg_miter_stop(&miter);  in sg_copy_buffer()
959 	struct sg_mapping_iter miter;  in sg_zero_buffer()  local
962 	sg_miter_start(&miter, sgl, nents, sg_flags);  in sg_zero_buffer()
964 	if (!sg_miter_skip(&miter, skip))  in sg_zero_buffer()
967 	while (offset < buflen && sg_miter_next(&miter)) {  in sg_zero_buffer()
970 		len = min(miter.length, buflen - offset);  in sg_zero_buffer()
971 		memset(miter.addr, 0, len);  in sg_zero_buffer()
976 	sg_miter_stop(&miter);  in sg_zero_buffer()