674 static void gcm_walk_start(struct gcm_sg_walk *gw, struct scatterlist *sg,  in gcm_walk_start()  argument
677 	memset(gw, 0, sizeof(*gw));  in gcm_walk_start()
678 	gw->walk_bytes_remain = len;  in gcm_walk_start()
679 	scatterwalk_start(&gw->walk, sg);  in gcm_walk_start()
682 static inline unsigned int _gcm_sg_clamp_and_map(struct gcm_sg_walk *gw)  in _gcm_sg_clamp_and_map()  argument
686 	gw->walk_bytes = scatterwalk_clamp(&gw->walk, gw->walk_bytes_remain);  in _gcm_sg_clamp_and_map()
687 	while (!gw->walk_bytes) {  in _gcm_sg_clamp_and_map()
688 		nextsg = sg_next(gw->walk.sg);  in _gcm_sg_clamp_and_map()
691 		scatterwalk_start(&gw->walk, nextsg);  in _gcm_sg_clamp_and_map()
692 		gw->walk_bytes = scatterwalk_clamp(&gw->walk,  in _gcm_sg_clamp_and_map()
693 						   gw->walk_bytes_remain);  in _gcm_sg_clamp_and_map()
695 	gw->walk_ptr = scatterwalk_map(&gw->walk);  in _gcm_sg_clamp_and_map()
696 	return gw->walk_bytes;  in _gcm_sg_clamp_and_map()
699 static inline void _gcm_sg_unmap_and_advance(struct gcm_sg_walk *gw,  in _gcm_sg_unmap_and_advance()  argument
702 	gw->walk_bytes_remain -= nbytes;  in _gcm_sg_unmap_and_advance()
703 	scatterwalk_unmap(&gw->walk);  in _gcm_sg_unmap_and_advance()
704 	scatterwalk_advance(&gw->walk, nbytes);  in _gcm_sg_unmap_and_advance()
705 	scatterwalk_done(&gw->walk, 0, gw->walk_bytes_remain);  in _gcm_sg_unmap_and_advance()
706 	gw->walk_ptr = NULL;  in _gcm_sg_unmap_and_advance()
709 static int gcm_in_walk_go(struct gcm_sg_walk *gw, unsigned int minbytesneeded)  in gcm_in_walk_go()  argument
713 	if (gw->buf_bytes && gw->buf_bytes >= minbytesneeded) {  in gcm_in_walk_go()
714 		gw->ptr = gw->buf;  in gcm_in_walk_go()
715 		gw->nbytes = gw->buf_bytes;  in gcm_in_walk_go()
719 	if (gw->walk_bytes_remain == 0) {  in gcm_in_walk_go()
720 		gw->ptr = NULL;  in gcm_in_walk_go()
721 		gw->nbytes = 0;  in gcm_in_walk_go()
725 	if (!_gcm_sg_clamp_and_map(gw)) {  in gcm_in_walk_go()
726 		gw->ptr = NULL;  in gcm_in_walk_go()
727 		gw->nbytes = 0;  in gcm_in_walk_go()
731 	if (!gw->buf_bytes && gw->walk_bytes >= minbytesneeded) {  in gcm_in_walk_go()
732 		gw->ptr = gw->walk_ptr;  in gcm_in_walk_go()
733 		gw->nbytes = gw->walk_bytes;  in gcm_in_walk_go()
738 		n = min(gw->walk_bytes, AES_BLOCK_SIZE - gw->buf_bytes);  in gcm_in_walk_go()
739 		memcpy(gw->buf + gw->buf_bytes, gw->walk_ptr, n);  in gcm_in_walk_go()
740 		gw->buf_bytes += n;  in gcm_in_walk_go()
741 		_gcm_sg_unmap_and_advance(gw, n);  in gcm_in_walk_go()
742 		if (gw->buf_bytes >= minbytesneeded) {  in gcm_in_walk_go()
743 			gw->ptr = gw->buf;  in gcm_in_walk_go()
744 			gw->nbytes = gw->buf_bytes;  in gcm_in_walk_go()
747 		if (!_gcm_sg_clamp_and_map(gw)) {  in gcm_in_walk_go()
748 			gw->ptr = NULL;  in gcm_in_walk_go()
749 			gw->nbytes = 0;  in gcm_in_walk_go()
755 	return gw->nbytes;  in gcm_in_walk_go()
758 static int gcm_out_walk_go(struct gcm_sg_walk *gw, unsigned int minbytesneeded)  in gcm_out_walk_go()  argument
760 	if (gw->walk_bytes_remain == 0) {  in gcm_out_walk_go()
761 		gw->ptr = NULL;  in gcm_out_walk_go()
762 		gw->nbytes = 0;  in gcm_out_walk_go()
766 	if (!_gcm_sg_clamp_and_map(gw)) {  in gcm_out_walk_go()
767 		gw->ptr = NULL;  in gcm_out_walk_go()
768 		gw->nbytes = 0;  in gcm_out_walk_go()
772 	if (gw->walk_bytes >= minbytesneeded) {  in gcm_out_walk_go()
773 		gw->ptr = gw->walk_ptr;  in gcm_out_walk_go()
774 		gw->nbytes = gw->walk_bytes;  in gcm_out_walk_go()
778 	scatterwalk_unmap(&gw->walk);  in gcm_out_walk_go()
779 	gw->walk_ptr = NULL;  in gcm_out_walk_go()
781 	gw->ptr = gw->buf;  in gcm_out_walk_go()
782 	gw->nbytes = sizeof(gw->buf);  in gcm_out_walk_go()
785 	return gw->nbytes;  in gcm_out_walk_go()
788 static int gcm_in_walk_done(struct gcm_sg_walk *gw, unsigned int bytesdone)  in gcm_in_walk_done()  argument
790 	if (gw->ptr == NULL)  in gcm_in_walk_done()
793 	if (gw->ptr == gw->buf) {  in gcm_in_walk_done()
794 		int n = gw->buf_bytes - bytesdone;  in gcm_in_walk_done()
796 			memmove(gw->buf, gw->buf + bytesdone, n);  in gcm_in_walk_done()
797 			gw->buf_bytes = n;  in gcm_in_walk_done()
799 			gw->buf_bytes = 0;  in gcm_in_walk_done()
801 		_gcm_sg_unmap_and_advance(gw, bytesdone);  in gcm_in_walk_done()
806 static int gcm_out_walk_done(struct gcm_sg_walk *gw, unsigned int bytesdone)  in gcm_out_walk_done()  argument
810 	if (gw->ptr == NULL)  in gcm_out_walk_done()
813 	if (gw->ptr == gw->buf) {  in gcm_out_walk_done()
815 			if (!_gcm_sg_clamp_and_map(gw))  in gcm_out_walk_done()
817 			n = min(gw->walk_bytes, bytesdone - i);  in gcm_out_walk_done()
818 			memcpy(gw->walk_ptr, gw->buf + i, n);  in gcm_out_walk_done()
819 			_gcm_sg_unmap_and_advance(gw, n);  in gcm_out_walk_done()
822 		_gcm_sg_unmap_and_advance(gw, bytesdone);  in gcm_out_walk_done()