673 static void gcm_walk_start(struct gcm_sg_walk *gw, struct scatterlist *sg,  in gcm_walk_start()  argument
676 	memset(gw, 0, sizeof(*gw));  in gcm_walk_start()
677 	gw->walk_bytes_remain = len;  in gcm_walk_start()
678 	scatterwalk_start(&gw->walk, sg);  in gcm_walk_start()
681 static inline unsigned int _gcm_sg_clamp_and_map(struct gcm_sg_walk *gw)  in _gcm_sg_clamp_and_map()  argument
685 	gw->walk_bytes = scatterwalk_clamp(&gw->walk, gw->walk_bytes_remain);  in _gcm_sg_clamp_and_map()
686 	while (!gw->walk_bytes) {  in _gcm_sg_clamp_and_map()
687 		nextsg = sg_next(gw->walk.sg);  in _gcm_sg_clamp_and_map()
690 		scatterwalk_start(&gw->walk, nextsg);  in _gcm_sg_clamp_and_map()
691 		gw->walk_bytes = scatterwalk_clamp(&gw->walk,  in _gcm_sg_clamp_and_map()
692 						   gw->walk_bytes_remain);  in _gcm_sg_clamp_and_map()
694 	gw->walk_ptr = scatterwalk_map(&gw->walk);  in _gcm_sg_clamp_and_map()
695 	return gw->walk_bytes;  in _gcm_sg_clamp_and_map()
698 static inline void _gcm_sg_unmap_and_advance(struct gcm_sg_walk *gw,  in _gcm_sg_unmap_and_advance()  argument
701 	gw->walk_bytes_remain -= nbytes;  in _gcm_sg_unmap_and_advance()
702 	scatterwalk_unmap(gw->walk_ptr);  in _gcm_sg_unmap_and_advance()
703 	scatterwalk_advance(&gw->walk, nbytes);  in _gcm_sg_unmap_and_advance()
704 	scatterwalk_done(&gw->walk, 0, gw->walk_bytes_remain);  in _gcm_sg_unmap_and_advance()
705 	gw->walk_ptr = NULL;  in _gcm_sg_unmap_and_advance()
708 static int gcm_in_walk_go(struct gcm_sg_walk *gw, unsigned int minbytesneeded)  in gcm_in_walk_go()  argument
712 	if (gw->buf_bytes && gw->buf_bytes >= minbytesneeded) {  in gcm_in_walk_go()
713 		gw->ptr = gw->buf;  in gcm_in_walk_go()
714 		gw->nbytes = gw->buf_bytes;  in gcm_in_walk_go()
718 	if (gw->walk_bytes_remain == 0) {  in gcm_in_walk_go()
719 		gw->ptr = NULL;  in gcm_in_walk_go()
720 		gw->nbytes = 0;  in gcm_in_walk_go()
724 	if (!_gcm_sg_clamp_and_map(gw)) {  in gcm_in_walk_go()
725 		gw->ptr = NULL;  in gcm_in_walk_go()
726 		gw->nbytes = 0;  in gcm_in_walk_go()
730 	if (!gw->buf_bytes && gw->walk_bytes >= minbytesneeded) {  in gcm_in_walk_go()
731 		gw->ptr = gw->walk_ptr;  in gcm_in_walk_go()
732 		gw->nbytes = gw->walk_bytes;  in gcm_in_walk_go()
737 		n = min(gw->walk_bytes, AES_BLOCK_SIZE - gw->buf_bytes);  in gcm_in_walk_go()
738 		memcpy(gw->buf + gw->buf_bytes, gw->walk_ptr, n);  in gcm_in_walk_go()
739 		gw->buf_bytes += n;  in gcm_in_walk_go()
740 		_gcm_sg_unmap_and_advance(gw, n);  in gcm_in_walk_go()
741 		if (gw->buf_bytes >= minbytesneeded) {  in gcm_in_walk_go()
742 			gw->ptr = gw->buf;  in gcm_in_walk_go()
743 			gw->nbytes = gw->buf_bytes;  in gcm_in_walk_go()
746 		if (!_gcm_sg_clamp_and_map(gw)) {  in gcm_in_walk_go()
747 			gw->ptr = NULL;  in gcm_in_walk_go()
748 			gw->nbytes = 0;  in gcm_in_walk_go()
754 	return gw->nbytes;  in gcm_in_walk_go()
757 static int gcm_out_walk_go(struct gcm_sg_walk *gw, unsigned int minbytesneeded)  in gcm_out_walk_go()  argument
759 	if (gw->walk_bytes_remain == 0) {  in gcm_out_walk_go()
760 		gw->ptr = NULL;  in gcm_out_walk_go()
761 		gw->nbytes = 0;  in gcm_out_walk_go()
765 	if (!_gcm_sg_clamp_and_map(gw)) {  in gcm_out_walk_go()
766 		gw->ptr = NULL;  in gcm_out_walk_go()
767 		gw->nbytes = 0;  in gcm_out_walk_go()
771 	if (gw->walk_bytes >= minbytesneeded) {  in gcm_out_walk_go()
772 		gw->ptr = gw->walk_ptr;  in gcm_out_walk_go()
773 		gw->nbytes = gw->walk_bytes;  in gcm_out_walk_go()
777 	scatterwalk_unmap(gw->walk_ptr);  in gcm_out_walk_go()
778 	gw->walk_ptr = NULL;  in gcm_out_walk_go()
780 	gw->ptr = gw->buf;  in gcm_out_walk_go()
781 	gw->nbytes = sizeof(gw->buf);  in gcm_out_walk_go()
784 	return gw->nbytes;  in gcm_out_walk_go()
787 static int gcm_in_walk_done(struct gcm_sg_walk *gw, unsigned int bytesdone)  in gcm_in_walk_done()  argument
789 	if (gw->ptr == NULL)  in gcm_in_walk_done()
792 	if (gw->ptr == gw->buf) {  in gcm_in_walk_done()
793 		int n = gw->buf_bytes - bytesdone;  in gcm_in_walk_done()
795 			memmove(gw->buf, gw->buf + bytesdone, n);  in gcm_in_walk_done()
796 			gw->buf_bytes = n;  in gcm_in_walk_done()
798 			gw->buf_bytes = 0;  in gcm_in_walk_done()
800 		_gcm_sg_unmap_and_advance(gw, bytesdone);  in gcm_in_walk_done()
805 static int gcm_out_walk_done(struct gcm_sg_walk *gw, unsigned int bytesdone)  in gcm_out_walk_done()  argument
809 	if (gw->ptr == NULL)  in gcm_out_walk_done()
812 	if (gw->ptr == gw->buf) {  in gcm_out_walk_done()
814 			if (!_gcm_sg_clamp_and_map(gw))  in gcm_out_walk_done()
816 			n = min(gw->walk_bytes, bytesdone - i);  in gcm_out_walk_done()
817 			memcpy(gw->walk_ptr, gw->buf + i, n);  in gcm_out_walk_done()
818 			_gcm_sg_unmap_and_advance(gw, n);  in gcm_out_walk_done()
821 		_gcm_sg_unmap_and_advance(gw, bytesdone);  in gcm_out_walk_done()