779 static void gcm_walk_start(struct gcm_sg_walk *gw, struct scatterlist *sg,  in gcm_walk_start()  argument
782 	memset(gw, 0, sizeof(*gw));  in gcm_walk_start()
783 	gw->walk_bytes_remain = len;  in gcm_walk_start()
784 	scatterwalk_start(&gw->walk, sg);  in gcm_walk_start()
787 static inline unsigned int _gcm_sg_clamp_and_map(struct gcm_sg_walk *gw)  in _gcm_sg_clamp_and_map()  argument
789 	if (gw->walk_bytes_remain == 0)  in _gcm_sg_clamp_and_map()
791 	gw->walk_bytes = scatterwalk_next(&gw->walk, gw->walk_bytes_remain);  in _gcm_sg_clamp_and_map()
792 	return gw->walk_bytes;  in _gcm_sg_clamp_and_map()
795 static inline void _gcm_sg_unmap_and_advance(struct gcm_sg_walk *gw,  in _gcm_sg_unmap_and_advance()  argument
798 	gw->walk_bytes_remain -= nbytes;  in _gcm_sg_unmap_and_advance()
800 		scatterwalk_done_dst(&gw->walk, nbytes);  in _gcm_sg_unmap_and_advance()
802 		scatterwalk_done_src(&gw->walk, nbytes);  in _gcm_sg_unmap_and_advance()
805 static int gcm_in_walk_go(struct gcm_sg_walk *gw, unsigned int minbytesneeded)  in gcm_in_walk_go()  argument
809 	if (gw->buf_bytes && gw->buf_bytes >= minbytesneeded) {  in gcm_in_walk_go()
810 		gw->ptr = gw->buf;  in gcm_in_walk_go()
811 		gw->nbytes = gw->buf_bytes;  in gcm_in_walk_go()
815 	if (gw->walk_bytes_remain == 0) {  in gcm_in_walk_go()
816 		gw->ptr = NULL;  in gcm_in_walk_go()
817 		gw->nbytes = 0;  in gcm_in_walk_go()
821 	if (!_gcm_sg_clamp_and_map(gw)) {  in gcm_in_walk_go()
822 		gw->ptr = NULL;  in gcm_in_walk_go()
823 		gw->nbytes = 0;  in gcm_in_walk_go()
827 	if (!gw->buf_bytes && gw->walk_bytes >= minbytesneeded) {  in gcm_in_walk_go()
828 		gw->ptr = gw->walk.addr;  in gcm_in_walk_go()
829 		gw->nbytes = gw->walk_bytes;  in gcm_in_walk_go()
834 		n = min(gw->walk_bytes, AES_BLOCK_SIZE - gw->buf_bytes);  in gcm_in_walk_go()
835 		memcpy(gw->buf + gw->buf_bytes, gw->walk.addr, n);  in gcm_in_walk_go()
836 		gw->buf_bytes += n;  in gcm_in_walk_go()
837 		_gcm_sg_unmap_and_advance(gw, n, false);  in gcm_in_walk_go()
838 		if (gw->buf_bytes >= minbytesneeded) {  in gcm_in_walk_go()
839 			gw->ptr = gw->buf;  in gcm_in_walk_go()
840 			gw->nbytes = gw->buf_bytes;  in gcm_in_walk_go()
843 		if (!_gcm_sg_clamp_and_map(gw)) {  in gcm_in_walk_go()
844 			gw->ptr = NULL;  in gcm_in_walk_go()
845 			gw->nbytes = 0;  in gcm_in_walk_go()
851 	return gw->nbytes;  in gcm_in_walk_go()
854 static int gcm_out_walk_go(struct gcm_sg_walk *gw, unsigned int minbytesneeded)  in gcm_out_walk_go()  argument
856 	if (gw->walk_bytes_remain == 0) {  in gcm_out_walk_go()
857 		gw->ptr = NULL;  in gcm_out_walk_go()
858 		gw->nbytes = 0;  in gcm_out_walk_go()
862 	if (!_gcm_sg_clamp_and_map(gw)) {  in gcm_out_walk_go()
863 		gw->ptr = NULL;  in gcm_out_walk_go()
864 		gw->nbytes = 0;  in gcm_out_walk_go()
868 	if (gw->walk_bytes >= minbytesneeded) {  in gcm_out_walk_go()
869 		gw->ptr = gw->walk.addr;  in gcm_out_walk_go()
870 		gw->nbytes = gw->walk_bytes;  in gcm_out_walk_go()
874 	scatterwalk_unmap(&gw->walk);  in gcm_out_walk_go()
876 	gw->ptr = gw->buf;  in gcm_out_walk_go()
877 	gw->nbytes = sizeof(gw->buf);  in gcm_out_walk_go()
880 	return gw->nbytes;  in gcm_out_walk_go()
883 static int gcm_in_walk_done(struct gcm_sg_walk *gw, unsigned int bytesdone)  in gcm_in_walk_done()  argument
885 	if (gw->ptr == NULL)  in gcm_in_walk_done()
888 	if (gw->ptr == gw->buf) {  in gcm_in_walk_done()
889 		int n = gw->buf_bytes - bytesdone;  in gcm_in_walk_done()
891 			memmove(gw->buf, gw->buf + bytesdone, n);  in gcm_in_walk_done()
892 			gw->buf_bytes = n;  in gcm_in_walk_done()
894 			gw->buf_bytes = 0;  in gcm_in_walk_done()
896 		_gcm_sg_unmap_and_advance(gw, bytesdone, false);  in gcm_in_walk_done()
901 static int gcm_out_walk_done(struct gcm_sg_walk *gw, unsigned int bytesdone)  in gcm_out_walk_done()  argument
905 	if (gw->ptr == NULL)  in gcm_out_walk_done()
908 	if (gw->ptr == gw->buf) {  in gcm_out_walk_done()
910 			if (!_gcm_sg_clamp_and_map(gw))  in gcm_out_walk_done()
912 			n = min(gw->walk_bytes, bytesdone - i);  in gcm_out_walk_done()
913 			memcpy(gw->walk.addr, gw->buf + i, n);  in gcm_out_walk_done()
914 			_gcm_sg_unmap_and_advance(gw, n, true);  in gcm_out_walk_done()
917 		_gcm_sg_unmap_and_advance(gw, bytesdone, true);  in gcm_out_walk_done()