use less confusing names for iov_iter direction initializers

READ/WRITE proved to be actively confusing - the meanings are
"data destination, as used with read(2)" and "data source, as
used with write(2)", but people keep interpreting those as
"we read data from it" and "we write data to it", i.e. exactly
the wrong way.

Call them ITER_DEST and ITER_SOURCE - at least that is harder
to misinterpret...

Signed-off-by: Al Viro <[e-mail]>

arch/s390/kernel/crash_dump.c

···
 
 	kvec.iov_base = dst;
 	kvec.iov_len = count;
-	iov_iter_kvec(&iter, READ, &kvec, 1, count);
+	iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, count);
 	if (copy_oldmem_iter(&iter, src, count) < count)
 		return -EFAULT;
 	return 0;

arch/s390/mm/maccess.c

···
 
 	kvec.iov_base = dest;
 	kvec.iov_len = count;
-	iov_iter_kvec(&iter, READ, &kvec, 1, count);
+	iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, count);
 	if (memcpy_real_iter(&iter, src, count) < count)
 		return -EFAULT;
 	return 0;

arch/x86/kernel/cpu/microcode/intel.c

···
 
 	kvec.iov_base = (void *)firmware->data;
 	kvec.iov_len = firmware->size;
-	iov_iter_kvec(&iter, WRITE, &kvec, 1, firmware->size);
+	iov_iter_kvec(&iter, ITER_SOURCE, &kvec, 1, firmware->size);
 	ret = generic_load_microcode(cpu, &iter);
 
 	release_firmware(firmware);

arch/x86/kernel/crash_dump_64.c

···
 	struct kvec kvec = { .iov_base = buf, .iov_len = count };
 	struct iov_iter iter;
 
-	iov_iter_kvec(&iter, READ, &kvec, 1, count);
+	iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, count);
 
 	return read_from_oldmem(&iter, count, ppos,
 				cc_platform_has(CC_ATTR_GUEST_MEM_ENCRYPT));

crypto/testmgr.c

···
 	struct iov_iter input;
 	int err;
 
-	iov_iter_kvec(&input, WRITE, inputs, nr_inputs, src_total_len);
+	iov_iter_kvec(&input, ITER_SOURCE, inputs, nr_inputs, src_total_len);
 	err = build_test_sglist(&tsgls->src, cfg->src_divs, alignmask,
 				cfg->inplace_mode != OUT_OF_PLACE ?
 					max(dst_total_len, src_total_len) :
···
 
 	kv.iov_base = (void *)vec->plaintext;
 	kv.iov_len = vec->psize;
-	iov_iter_kvec(&input, WRITE, &kv, 1, vec->psize);
+	iov_iter_kvec(&input, ITER_SOURCE, &kv, 1, vec->psize);
 	return build_test_sglist(tsgl, cfg->src_divs, alignmask, vec->psize,
 				 &input, divs);
 }

drivers/acpi/pfr_update.c

···
 
 	iov.iov_base = (void __user *)buf;
 	iov.iov_len = len;
-	iov_iter_init(&iter, WRITE, &iov, 1, len);
+	iov_iter_init(&iter, ITER_SOURCE, &iov, 1, len);
 
 	/* map the communication buffer */
 	phy_addr = (phys_addr_t)((buf_info.addr_hi << 32) | buf_info.addr_lo);

drivers/block/drbd/drbd_main.c

···
 
 	/* THINK  if (signal_pending) return ... ? */
 
-	iov_iter_kvec(&msg.msg_iter, WRITE, &iov, 1, size);
+	iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, &iov, 1, size);
 
 	if (sock == connection->data.socket) {
 		rcu_read_lock();

drivers/block/drbd/drbd_receiver.c

···
 	struct msghdr msg = {
 		.msg_flags = (flags ? flags : MSG_WAITALL | MSG_NOSIGNAL)
 	};
-	iov_iter_kvec(&msg.msg_iter, READ, &iov, 1, size);
+	iov_iter_kvec(&msg.msg_iter, ITER_DEST, &iov, 1, size);
 	return sock_recvmsg(sock, &msg, msg.msg_flags);
 }
 

drivers/block/loop.c

···
 	struct iov_iter i;
 	ssize_t bw;
 
-	iov_iter_bvec(&i, WRITE, bvec, 1, bvec->bv_len);
+	iov_iter_bvec(&i, ITER_SOURCE, bvec, 1, bvec->bv_len);
 
 	file_start_write(file);
 	bw = vfs_iter_write(file, &i, ppos, 0);
···
 	ssize_t len;
 
 	rq_for_each_segment(bvec, rq, iter) {
-		iov_iter_bvec(&i, READ, &bvec, 1, bvec.bv_len);
+		iov_iter_bvec(&i, ITER_DEST, &bvec, 1, bvec.bv_len);
 		len = vfs_iter_read(lo->lo_backing_file, &i, &pos, 0);
 		if (len < 0)
 			return len;
···
 }
 
 static int lo_rw_aio(struct loop_device *lo, struct loop_cmd *cmd,
-		     loff_t pos, bool rw)
+		     loff_t pos, int rw)
 {
 	struct iov_iter iter;
 	struct req_iterator rq_iter;
···
 	cmd->iocb.ki_flags = IOCB_DIRECT;
 	cmd->iocb.ki_ioprio = IOPRIO_PRIO_VALUE(IOPRIO_CLASS_NONE, 0);
 
-	if (rw == WRITE)
+	if (rw == ITER_SOURCE)
 		ret = call_write_iter(file, &cmd->iocb, &iter);
 	else
 		ret = call_read_iter(file, &cmd->iocb, &iter);
···
 		return lo_fallocate(lo, rq, pos, FALLOC_FL_PUNCH_HOLE);
 	case REQ_OP_WRITE:
 		if (cmd->use_aio)
-			return lo_rw_aio(lo, cmd, pos, WRITE);
+			return lo_rw_aio(lo, cmd, pos, ITER_SOURCE);
 		else
 			return lo_write_simple(lo, rq, pos);
 	case REQ_OP_READ:
 		if (cmd->use_aio)
-			return lo_rw_aio(lo, cmd, pos, READ);
+			return lo_rw_aio(lo, cmd, pos, ITER_DEST);
 		else
 			return lo_read_simple(lo, rq, pos);
 	default:

drivers/block/nbd.c

···
 	u32 nbd_cmd_flags = 0;
 	int sent = nsock->sent, skip = 0;
 
-	iov_iter_kvec(&from, WRITE, &iov, 1, sizeof(request));
+	iov_iter_kvec(&from, ITER_SOURCE, &iov, 1, sizeof(request));
 
 	type = req_to_nbd_cmd_type(req);
 	if (type == U32_MAX)
···
 
 			dev_dbg(nbd_to_dev(nbd), "request %p: sending %d bytes data\n",
 				req, bvec.bv_len);
-			iov_iter_bvec(&from, WRITE, &bvec, 1, bvec.bv_len);
+			iov_iter_bvec(&from, ITER_SOURCE, &bvec, 1, bvec.bv_len);
 			if (skip) {
 				if (skip >= iov_iter_count(&from)) {
 					skip -= iov_iter_count(&from);
···
 	int result;
 
 	reply->magic = 0;
-	iov_iter_kvec(&to, READ, &iov, 1, sizeof(*reply));
+	iov_iter_kvec(&to, ITER_DEST, &iov, 1, sizeof(*reply));
 	result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
 	if (result < 0) {
 		if (!nbd_disconnected(nbd->config))
···
 		struct iov_iter to;
 
 		rq_for_each_segment(bvec, req, iter) {
-			iov_iter_bvec(&to, READ, &bvec, 1, bvec.bv_len);
+			iov_iter_bvec(&to, ITER_DEST, &bvec, 1, bvec.bv_len);
 			result = sock_xmit(nbd, index, 0, &to, MSG_WAITALL, NULL);
 			if (result < 0) {
 				dev_err(disk_to_dev(nbd->disk), "Receive data failed (result %d)\n",
···
 	for (i = 0; i < config->num_connections; i++) {
 		struct nbd_sock *nsock = config->socks[i];
 
-		iov_iter_kvec(&from, WRITE, &iov, 1, sizeof(request));
+		iov_iter_kvec(&from, ITER_SOURCE, &iov, 1, sizeof(request));
 		mutex_lock(&nsock->tx_lock);
 		ret = sock_xmit(nbd, i, 1, &from, 0, NULL);
 		if (ret < 0)

drivers/char/random.c

···
 			return ret;
 	}
 
-	ret = import_single_range(READ, ubuf, len, &iov, &iter);
+	ret = import_single_range(ITER_DEST, ubuf, len, &iov, &iter);
 	if (unlikely(ret))
 		return ret;
 	return get_random_bytes_user(&iter);
···
 			return -EINVAL;
 		if (get_user(len, p++))
 			return -EFAULT;
-		ret = import_single_range(WRITE, p, len, &iov, &iter);
+		ret = import_single_range(ITER_SOURCE, p, len, &iov, &iter);
 		if (unlikely(ret))
 			return ret;
 		ret = write_pool_user(&iter);

drivers/fsi/fsi-sbefifo.c

···
 	}
         ffdc_iov.iov_base = ffdc;
 	ffdc_iov.iov_len = SBEFIFO_MAX_FFDC_SIZE;
-        iov_iter_kvec(&ffdc_iter, READ, &ffdc_iov, 1, SBEFIFO_MAX_FFDC_SIZE);
+        iov_iter_kvec(&ffdc_iter, ITER_DEST, &ffdc_iov, 1, SBEFIFO_MAX_FFDC_SIZE);
 	cmd[0] = cpu_to_be32(2);
 	cmd[1] = cpu_to_be32(SBEFIFO_CMD_GET_SBE_FFDC);
 	rc = sbefifo_do_command(sbefifo, cmd, 2, &ffdc_iter);
···
 	rbytes = (*resp_len) * sizeof(__be32);
 	resp_iov.iov_base = response;
 	resp_iov.iov_len = rbytes;
-        iov_iter_kvec(&resp_iter, READ, &resp_iov, 1, rbytes);
+        iov_iter_kvec(&resp_iter, ITER_DEST, &resp_iov, 1, rbytes);
 
 	/* Perform the command */
 	rc = mutex_lock_interruptible(&sbefifo->lock);
···
 	/* Prepare iov iterator */
 	resp_iov.iov_base = buf;
 	resp_iov.iov_len = len;
-	iov_iter_init(&resp_iter, READ, &resp_iov, 1, len);
+	iov_iter_init(&resp_iter, ITER_DEST, &resp_iov, 1, len);
 
 	/* Perform the command */
 	rc = mutex_lock_interruptible(&sbefifo->lock);

drivers/infiniband/ulp/rtrs/rtrs-clt.c

···
 	refcount_set(&req->ref, 1);
 	req->mp_policy = clt_path->clt->mp_policy;
 
-	iov_iter_kvec(&iter, WRITE, vec, 1, usr_len);
+	iov_iter_kvec(&iter, ITER_SOURCE, vec, 1, usr_len);
 	len = _copy_from_iter(req->iu->buf, usr_len, &iter);
 	WARN_ON(len != usr_len);
 

drivers/isdn/mISDN/l1oip_core.c

···
 		printk(KERN_DEBUG "%s: socket created and open\n",
 		       __func__);
 	while (!signal_pending(current)) {
-		iov_iter_kvec(&msg.msg_iter, READ, &iov, 1, recvbuf_size);
+		iov_iter_kvec(&msg.msg_iter, ITER_DEST, &iov, 1, recvbuf_size);
 		recvlen = sock_recvmsg(socket, &msg, 0);
 		if (recvlen > 0) {
 			l1oip_socket_parse(hc, &sin_rx, recvbuf, recvlen);

drivers/misc/vmw_vmci/vmci_queue_pair.c

···
 	if (!qpair || !buf)
 		return VMCI_ERROR_INVALID_ARGS;
 
-	iov_iter_kvec(&from, WRITE, &v, 1, buf_size);
+	iov_iter_kvec(&from, ITER_SOURCE, &v, 1, buf_size);
 
 	qp_lock(qpair);
 
···
 	if (!qpair || !buf)
 		return VMCI_ERROR_INVALID_ARGS;
 
-	iov_iter_kvec(&to, READ, &v, 1, buf_size);
+	iov_iter_kvec(&to, ITER_DEST, &v, 1, buf_size);
 
 	qp_lock(qpair);
 
···
 	if (!qpair || !buf)
 		return VMCI_ERROR_INVALID_ARGS;
 
-	iov_iter_kvec(&to, READ, &v, 1, buf_size);
+	iov_iter_kvec(&to, ITER_DEST, &v, 1, buf_size);
 
 	qp_lock(qpair);
 

drivers/net/ppp/ppp_generic.c

···
 	ret = -EFAULT;
 	iov.iov_base = buf;
 	iov.iov_len = count;
-	iov_iter_init(&to, READ, &iov, 1, count);
+	iov_iter_init(&to, ITER_DEST, &iov, 1, count);
 	if (skb_copy_datagram_iter(skb, 0, &to, skb->len))
 		goto outf;
 	ret = skb->len;

drivers/nvme/host/tcp.c

···
 	if (!iov_iter_count(&req->iter) &&
 	    req->data_sent < req->data_len) {
 		req->curr_bio = req->curr_bio->bi_next;
-		nvme_tcp_init_iter(req, WRITE);
+		nvme_tcp_init_iter(req, ITER_SOURCE);
 	}
 }
 
···
 				nvme_tcp_init_recv_ctx(queue);
 				return -EIO;
 			}
-			nvme_tcp_init_iter(req, READ);
+			nvme_tcp_init_iter(req, ITER_DEST);
 		}
 
 		/* we can read only from what is left in this bio */

drivers/nvme/target/io-cmd-file.c

···
 		if (req->cmd->rw.control & cpu_to_le16(NVME_RW_FUA))
 			ki_flags |= IOCB_DSYNC;
 		call_iter = req->ns->file->f_op->write_iter;
-		rw = WRITE;
+		rw = ITER_SOURCE;
 	} else {
 		call_iter = req->ns->file->f_op->read_iter;
-		rw = READ;
+		rw = ITER_DEST;
 	}
 
 	iov_iter_bvec(&iter, rw, req->f.bvec, nr_segs, count);

drivers/nvme/target/tcp.c

···
 		sg_offset = 0;
 	}
 
-	iov_iter_bvec(&cmd->recv_msg.msg_iter, READ, cmd->iov,
+	iov_iter_bvec(&cmd->recv_msg.msg_iter, ITER_DEST, cmd->iov,
 		      nr_pages, cmd->pdu_len);
 }
 

drivers/s390/char/zcore.c

···
 
 	kvec.iov_base = dst;
 	kvec.iov_len = count;
-	iov_iter_kvec(&iter, READ, &kvec, 1, count);
+	iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, count);
 	if (memcpy_hsa_iter(&iter, src, count) < count)
 		return -EIO;
 	return 0;

drivers/scsi/sg.c

···
 	Sg_scatter_hold *rsv_schp = &sfp->reserve;
 	struct request_queue *q = sfp->parentdp->device->request_queue;
 	struct rq_map_data *md, map_data;
-	int rw = hp->dxfer_direction == SG_DXFER_TO_DEV ? WRITE : READ;
+	int rw = hp->dxfer_direction == SG_DXFER_TO_DEV ? ITER_SOURCE : ITER_DEST;
 	struct scsi_cmnd *scmd;
 
 	SCSI_LOG_TIMEOUT(4, sg_printk(KERN_INFO, sfp->parentdp,

drivers/target/iscsi/iscsi_target_util.c

···
 		return -1;
 
 	memset(&msg, 0, sizeof(struct msghdr));
-	iov_iter_kvec(&msg.msg_iter, READ, iov, iov_count, data);
+	iov_iter_kvec(&msg.msg_iter, ITER_DEST, iov, iov_count, data);
 
 	while (msg_data_left(&msg)) {
 		rx_loop = sock_recvmsg(conn->sock, &msg, MSG_WAITALL);
···
 
 	memset(&msg, 0, sizeof(struct msghdr));
 
-	iov_iter_kvec(&msg.msg_iter, WRITE, iov, iov_count, data);
+	iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, iov, iov_count, data);
 
 	while (msg_data_left(&msg)) {
 		int tx_loop = sock_sendmsg(conn->sock, &msg);

drivers/target/target_core_file.c

···
 		len += se_dev->dev_attrib.block_size;
 	}
 
-	iov_iter_bvec(&iter, WRITE, bvec, nolb, len);
+	iov_iter_bvec(&iter, ITER_SOURCE, bvec, nolb, len);
 	ret = vfs_iter_write(fd_dev->fd_file, &iter, &pos, 0);
 
 	kfree(bvec);

drivers/usb/usbip/usbip_common.c

···
 	if (!sock || !buf || !size)
 		return -EINVAL;
 
-	iov_iter_kvec(&msg.msg_iter, READ, &iov, 1, size);
+	iov_iter_kvec(&msg.msg_iter, ITER_DEST, &iov, 1, size);
 
 	usbip_dbg_xmit("enter\n");
 

drivers/vhost/net.c

···
 	/* Skip header. TODO: support TSO. */
 	size_t len = iov_length(vq->iov, out);
 
-	iov_iter_init(iter, WRITE, vq->iov, out, len);
+	iov_iter_init(iter, ITER_SOURCE, vq->iov, out, len);
 	iov_iter_advance(iter, hdr_size);
 
 	return iov_iter_count(iter);
···
 			msg.msg_control = vhost_net_buf_consume(&nvq->rxq);
 		/* On overrun, truncate and discard */
 		if (unlikely(headcount > UIO_MAXIOV)) {
-			iov_iter_init(&msg.msg_iter, READ, vq->iov, 1, 1);
+			iov_iter_init(&msg.msg_iter, ITER_DEST, vq->iov, 1, 1);
 			err = sock->ops->recvmsg(sock, &msg,
 						 1, MSG_DONTWAIT | MSG_TRUNC);
 			pr_debug("Discarded rx packet: len %zd\n", sock_len);
 			continue;
 		}
 		/* We don't need to be notified again. */
-		iov_iter_init(&msg.msg_iter, READ, vq->iov, in, vhost_len);
+		iov_iter_init(&msg.msg_iter, ITER_DEST, vq->iov, in, vhost_len);
 		fixup = msg.msg_iter;
 		if (unlikely((vhost_hlen))) {
 			/* We will supply the header ourselves

drivers/vhost/scsi.c

···
 		memcpy(v_rsp.sense, cmd->tvc_sense_buf,
 		       se_cmd->scsi_sense_length);
 
-		iov_iter_init(&iov_iter, READ, &cmd->tvc_resp_iov,
+		iov_iter_init(&iov_iter, ITER_DEST, &cmd->tvc_resp_iov,
 			      cmd->tvc_in_iovs, sizeof(v_rsp));
 		ret = copy_to_iter(&v_rsp, sizeof(v_rsp), &iov_iter);
 		if (likely(ret == sizeof(v_rsp))) {
···
 	 * point at the start of the outgoing WRITE payload, if
 	 * DMA_TO_DEVICE is set.
 	 */
-	iov_iter_init(&vc->out_iter, WRITE, vq->iov, vc->out, vc->out_size);
+	iov_iter_init(&vc->out_iter, ITER_SOURCE, vq->iov, vc->out, vc->out_size);
 	ret = 0;
 
 done:
···
 			data_direction = DMA_FROM_DEVICE;
 			exp_data_len = vc.in_size - vc.rsp_size;
 
-			iov_iter_init(&in_iter, READ, &vq->iov[vc.out], vc.in,
+			iov_iter_init(&in_iter, ITER_DEST, &vq->iov[vc.out], vc.in,
 				      vc.rsp_size + exp_data_len);
 			iov_iter_advance(&in_iter, vc.rsp_size);
 			data_iter = in_iter;
···
 	memset(&rsp, 0, sizeof(rsp));
 	rsp.response = tmf_resp_code;
 
-	iov_iter_init(&iov_iter, READ, resp_iov, in_iovs, sizeof(rsp));
+	iov_iter_init(&iov_iter, ITER_DEST, resp_iov, in_iovs, sizeof(rsp));
 
 	ret = copy_to_iter(&rsp, sizeof(rsp), &iov_iter);
 	if (likely(ret == sizeof(rsp)))
···
 	memset(&rsp, 0, sizeof(rsp));	/* event_actual = 0 */
 	rsp.response = VIRTIO_SCSI_S_OK;
 
-	iov_iter_init(&iov_iter, READ, &vq->iov[vc->out], vc->in, sizeof(rsp));
+	iov_iter_init(&iov_iter, ITER_DEST, &vq->iov[vc->out], vc->in, sizeof(rsp));
 
 	ret = copy_to_iter(&rsp, sizeof(rsp), &iov_iter);
 	if (likely(ret == sizeof(rsp)))

drivers/vhost/vhost.c

···
 				     VHOST_ACCESS_WO);
 		if (ret < 0)
 			goto out;
-		iov_iter_init(&t, READ, vq->iotlb_iov, ret, size);
+		iov_iter_init(&t, ITER_DEST, vq->iotlb_iov, ret, size);
 		ret = copy_to_iter(from, size, &t);
 		if (ret == size)
 			ret = 0;
···
 			       (unsigned long long) size);
 			goto out;
 		}
-		iov_iter_init(&f, WRITE, vq->iotlb_iov, ret, size);
+		iov_iter_init(&f, ITER_SOURCE, vq->iotlb_iov, ret, size);
 		ret = copy_from_iter(to, size, &f);
 		if (ret == size)
 			ret = 0;
···
 			vq_err(vq, "Translation failure %d in indirect.\n", ret);
 		return ret;
 	}
-	iov_iter_init(&from, WRITE, vq->indirect, ret, len);
+	iov_iter_init(&from, ITER_SOURCE, vq->indirect, ret, len);
 	count = len / sizeof desc;
 	/* Buffers are chained via a 16 bit next field, so
 	 * we can have at most 2^16 of these. */

drivers/vhost/vringh.c

···
 		else if (ret < 0)
 			return ret;
 
-		iov_iter_bvec(&iter, WRITE, iov, ret, translated);
+		iov_iter_bvec(&iter, ITER_SOURCE, iov, ret, translated);
 
 		ret = copy_from_iter(dst, translated, &iter);
 		if (ret < 0)
···
 		else if (ret < 0)
 			return ret;
 
-		iov_iter_bvec(&iter, READ, iov, ret, translated);
+		iov_iter_bvec(&iter, ITER_DEST, iov, ret, translated);
 
 		ret = copy_to_iter(src, translated, &iter);
 		if (ret < 0)

drivers/vhost/vsock.c

···
 			break;
 		}
 
-		iov_iter_init(&iov_iter, READ, &vq->iov[out], in, iov_len);
+		iov_iter_init(&iov_iter, ITER_DEST, &vq->iov[out], in, iov_len);
 		payload_len = pkt->len - pkt->off;
 
 		/* If the packet is greater than the space available in the
···
 		return NULL;
 
 	len = iov_length(vq->iov, out);
-	iov_iter_init(&iov_iter, WRITE, vq->iov, out, len);
+	iov_iter_init(&iov_iter, ITER_SOURCE, vq->iov, out, len);
 
 	nbytes = copy_from_iter(&pkt->hdr, sizeof(pkt->hdr), &iov_iter);
 	if (nbytes != sizeof(pkt->hdr)) {

drivers/xen/pvcalls-back.c

···
 	if (masked_prod < masked_cons) {
 		vec[0].iov_base = data->in + masked_prod;
 		vec[0].iov_len = wanted;
-		iov_iter_kvec(&msg.msg_iter, READ, vec, 1, wanted);
+		iov_iter_kvec(&msg.msg_iter, ITER_DEST, vec, 1, wanted);
 	} else {
 		vec[0].iov_base = data->in + masked_prod;
 		vec[0].iov_len = array_size - masked_prod;
 		vec[1].iov_base = data->in;
 		vec[1].iov_len = wanted - vec[0].iov_len;
-		iov_iter_kvec(&msg.msg_iter, READ, vec, 2, wanted);
+		iov_iter_kvec(&msg.msg_iter, ITER_DEST, vec, 2, wanted);
 	}
 
 	atomic_set(&map->read, 0);
···
 	if (pvcalls_mask(prod, array_size) > pvcalls_mask(cons, array_size)) {
 		vec[0].iov_base = data->out + pvcalls_mask(cons, array_size);
 		vec[0].iov_len = size;
-		iov_iter_kvec(&msg.msg_iter, WRITE, vec, 1, size);
+		iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, vec, 1, size);
 	} else {
 		vec[0].iov_base = data->out + pvcalls_mask(cons, array_size);
 		vec[0].iov_len = array_size - pvcalls_mask(cons, array_size);
 		vec[1].iov_base = data->out;
 		vec[1].iov_len = size - vec[0].iov_len;
-		iov_iter_kvec(&msg.msg_iter, WRITE, vec, 2, size);
+		iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, vec, 2, size);
 	}
 
 	atomic_set(&map->write, 0);

fs/9p/vfs_addr.c

···
 	size_t len = subreq->len   - subreq->transferred;
 	int total, err;
 
-	iov_iter_xarray(&to, READ, &rreq->mapping->i_pages, pos, len);
+	iov_iter_xarray(&to, ITER_DEST, &rreq->mapping->i_pages, pos, len);
 
 	total = p9_client_read(fid, pos, &to, &err);
 
···
 
 	len = min_t(loff_t, i_size - start, len);
 
-	iov_iter_xarray(&from, WRITE, &folio_mapping(folio)->i_pages, start, len);
+	iov_iter_xarray(&from, ITER_SOURCE, &folio_mapping(folio)->i_pages, start, len);
 
 	/* We should have writeback_fid always set */
 	BUG_ON(!v9inode->writeback_fid);

fs/9p/vfs_dir.c

···
 			struct iov_iter to;
 			int n;
 
-			iov_iter_kvec(&to, READ, &kvec, 1, buflen);
+			iov_iter_kvec(&to, ITER_DEST, &kvec, 1, buflen);
 			n = p9_client_read(file->private_data, ctx->pos, &to,
 					   &err);
 			if (err)

fs/9p/xattr.c

···
 	struct iov_iter to;
 	int err;
 
-	iov_iter_kvec(&to, READ, &kvec, 1, buffer_size);
+	iov_iter_kvec(&to, ITER_DEST, &kvec, 1, buffer_size);
 
 	attr_fid = p9_client_xattrwalk(fid, name, &attr_size);
 	if (IS_ERR(attr_fid)) {
···
 	struct iov_iter from;
 	int retval, err;
 
-	iov_iter_kvec(&from, WRITE, &kvec, 1, value_len);
+	iov_iter_kvec(&from, ITER_SOURCE, &kvec, 1, value_len);
 
 	p9_debug(P9_DEBUG_VFS, "name = %s value_len = %zu flags = %d\n",
 		 name, value_len, flags);

fs/afs/cmservice.c

···
 		if (call->count2 != call->count && call->count2 != 0)
 			return afs_protocol_error(call, afs_eproto_cb_count);
 		call->iter = &call->def_iter;
-		iov_iter_discard(&call->def_iter, READ, call->count2 * 3 * 4);
+		iov_iter_discard(&call->def_iter, ITER_DEST, call->count2 * 3 * 4);
 		call->unmarshall++;
 
 		fallthrough;

fs/afs/dir.c

···
 	req->actual_len = i_size; /* May change */
 	req->len = nr_pages * PAGE_SIZE; /* We can ask for more than there is */
 	req->data_version = dvnode->status.data_version; /* May change */
-	iov_iter_xarray(&req->def_iter, READ, &dvnode->netfs.inode.i_mapping->i_pages,
+	iov_iter_xarray(&req->def_iter, ITER_DEST, &dvnode->netfs.inode.i_mapping->i_pages,
 			0, i_size);
 	req->iter = &req->def_iter;
 

fs/afs/file.c

···
 	fsreq->vnode	= vnode;
 	fsreq->iter	= &fsreq->def_iter;
 
-	iov_iter_xarray(&fsreq->def_iter, READ,
+	iov_iter_xarray(&fsreq->def_iter, ITER_DEST,
 			&fsreq->vnode->netfs.inode.i_mapping->i_pages,
 			fsreq->pos, fsreq->len);
 
···
 	fsreq->len	= folio_size(folio);
 	fsreq->vnode	= vnode;
 	fsreq->iter	= &fsreq->def_iter;
-	iov_iter_xarray(&fsreq->def_iter, READ, &folio->mapping->i_pages,
+	iov_iter_xarray(&fsreq->def_iter, ITER_DEST, &folio->mapping->i_pages,
 			fsreq->pos, fsreq->len);
 
 	ret = afs_fetch_data(fsreq->vnode, fsreq);

fs/afs/internal.h

···
 	call->iov_len = size;
 	call->kvec[0].iov_base = buf;
 	call->kvec[0].iov_len = size;
-	iov_iter_kvec(&call->def_iter, READ, call->kvec, 1, size);
+	iov_iter_kvec(&call->def_iter, ITER_DEST, call->kvec, 1, size);
 }
 
 static inline void afs_extract_to_tmp(struct afs_call *call)
···
 static inline void afs_extract_discard(struct afs_call *call, size_t size)
 {
 	call->iov_len = size;
-	iov_iter_discard(&call->def_iter, READ, size);
+	iov_iter_discard(&call->def_iter, ITER_DEST, size);
 }
 
 static inline void afs_extract_to_buf(struct afs_call *call, size_t size)

fs/afs/rxrpc.c

···
 
 	msg.msg_name		= NULL;
 	msg.msg_namelen		= 0;
-	iov_iter_kvec(&msg.msg_iter, WRITE, iov, 1, call->request_size);
+	iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, iov, 1, call->request_size);
 	msg.msg_control		= NULL;
 	msg.msg_controllen	= 0;
 	msg.msg_flags		= MSG_WAITALL | (call->write_iter ? MSG_MORE : 0);
···
 					RX_USER_ABORT, ret, "KSD");
 	} else {
 		len = 0;
-		iov_iter_kvec(&msg.msg_iter, READ, NULL, 0, 0);
+		iov_iter_kvec(&msg.msg_iter, ITER_DEST, NULL, 0, 0);
 		rxrpc_kernel_recv_data(call->net->socket, rxcall,
 				       &msg.msg_iter, &len, false,
 				       &call->abort_code, &call->service_id);
···
 	       ) {
 		if (state == AFS_CALL_SV_AWAIT_ACK) {
 			len = 0;
-			iov_iter_kvec(&call->def_iter, READ, NULL, 0, 0);
+			iov_iter_kvec(&call->def_iter, ITER_DEST, NULL, 0, 0);
 			ret = rxrpc_kernel_recv_data(call->net->socket,
 						     call->rxcall, &call->def_iter,
 						     &len, false, &remote_abort,
···
 
 	msg.msg_name		= NULL;
 	msg.msg_namelen		= 0;
-	iov_iter_kvec(&msg.msg_iter, WRITE, NULL, 0, 0);
+	iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, NULL, 0, 0);
 	msg.msg_control		= NULL;
 	msg.msg_controllen	= 0;
 	msg.msg_flags		= 0;
···
 	iov[0].iov_len		= len;
 	msg.msg_name		= NULL;
 	msg.msg_namelen		= 0;
-	iov_iter_kvec(&msg.msg_iter, WRITE, iov, 1, len);
+	iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, iov, 1, len);
 	msg.msg_control		= NULL;
 	msg.msg_controllen	= 0;
 	msg.msg_flags		= 0;

fs/afs/write.c

···
 		 */
 		afs_write_to_cache(vnode, start, len, i_size, caching);
 
-		iov_iter_xarray(&iter, WRITE, &mapping->i_pages, start, len);
+		iov_iter_xarray(&iter, ITER_SOURCE, &mapping->i_pages, start, len);
 		ret = afs_store_data(vnode, &iter, start, false);
 	} else {
 		_debug("write discard %x @%llx [%llx]", len, start, i_size);
···
 		bv[0].bv_page = &folio->page;
 		bv[0].bv_offset = f;
 		bv[0].bv_len = t - f;
-		iov_iter_bvec(&iter, WRITE, bv, 1, bv[0].bv_len);
+		iov_iter_bvec(&iter, ITER_SOURCE, bv, 1, bv[0].bv_len);
 
 		trace_afs_folio_dirty(vnode, tracepoint_string("launder"), folio);
 		ret = afs_store_data(vnode, &iter, folio_pos(folio) + f, true);

fs/aio.c

···
 	if (unlikely(!file->f_op->read_iter))
 		return -EINVAL;
 
-	ret = aio_setup_rw(READ, iocb, &iovec, vectored, compat, &iter);
+	ret = aio_setup_rw(ITER_DEST, iocb, &iovec, vectored, compat, &iter);
 	if (ret < 0)
 		return ret;
 	ret = rw_verify_area(READ, file, &req->ki_pos, iov_iter_count(&iter));
···
 	if (unlikely(!file->f_op->write_iter))
 		return -EINVAL;
 
-	ret = aio_setup_rw(WRITE, iocb, &iovec, vectored, compat, &iter);
+	ret = aio_setup_rw(ITER_SOURCE, iocb, &iovec, vectored, compat, &iter);
 	if (ret < 0)
 		return ret;
 	ret = rw_verify_area(WRITE, file, &req->ki_pos, iov_iter_count(&iter));

fs/btrfs/ioctl.c

···
 		goto out_acct;
 	}
 
-	ret = import_iovec(READ, args.iov, args.iovcnt, ARRAY_SIZE(iovstack),
+	ret = import_iovec(ITER_DEST, args.iov, args.iovcnt, ARRAY_SIZE(iovstack),
 			   &iov, &iter);
 	if (ret < 0)
 		goto out_acct;
···
 	if (args.len > args.unencoded_len - args.unencoded_offset)
 		goto out_acct;
 
-	ret = import_iovec(WRITE, args.iov, args.iovcnt, ARRAY_SIZE(iovstack),
+	ret = import_iovec(ITER_SOURCE, args.iov, args.iovcnt, ARRAY_SIZE(iovstack),
 			   &iov, &iter);
 	if (ret < 0)
 		goto out_acct;

fs/ceph/addr.c

···
 	}
 
 	len = min_t(size_t, iinfo->inline_len - subreq->start, subreq->len);
-	iov_iter_xarray(&iter, READ, &rreq->mapping->i_pages, subreq->start, len);
+	iov_iter_xarray(&iter, ITER_DEST, &rreq->mapping->i_pages, subreq->start, len);
 	err = copy_to_iter(iinfo->inline_data + subreq->start, len, &iter);
 	if (err == 0)
 		err = -EFAULT;
···
 	}
 
 	dout("%s: pos=%llu orig_len=%zu len=%llu\n", __func__, subreq->start, subreq->len, len);
-	iov_iter_xarray(&iter, READ, &rreq->mapping->i_pages, subreq->start, len);
+	iov_iter_xarray(&iter, ITER_DEST, &rreq->mapping->i_pages, subreq->start, len);
 	err = iov_iter_get_pages_alloc2(&iter, &pages, len, &page_off);
 	if (err < 0) {
 		dout("%s: iov_ter_get_pages_alloc returned %d\n", __func__, err);

fs/ceph/file.c

···
 				aio_req->total_len = rc + zlen;
 			}
 
-			iov_iter_bvec(&i, READ, osd_data->bvec_pos.bvecs,
+			iov_iter_bvec(&i, ITER_DEST, osd_data->bvec_pos.bvecs,
 				      osd_data->num_bvecs, len);
 			iov_iter_advance(&i, rc);
 			iov_iter_zero(zlen, &i);
···
 				int zlen = min_t(size_t, len - ret,
 						 size - pos - ret);
 
-				iov_iter_bvec(&i, READ, bvecs, num_pages, len);
+				iov_iter_bvec(&i, ITER_DEST, bvecs, num_pages, len);
 				iov_iter_advance(&i, ret);
 				iov_iter_zero(zlen, &i);
 				ret += zlen;

fs/cifs/connect.c

···
 {
 	struct msghdr smb_msg = {};
 	struct kvec iov = {.iov_base = buf, .iov_len = to_read};
-	iov_iter_kvec(&smb_msg.msg_iter, READ, &iov, 1, to_read);
+	iov_iter_kvec(&smb_msg.msg_iter, ITER_DEST, &iov, 1, to_read);
 
 	return cifs_readv_from_socket(server, &smb_msg);
 }
···
 	 *  and cifs_readv_from_socket sets msg_control and msg_controllen
 	 *  so little to initialize in struct msghdr
 	 */
-	iov_iter_discard(&smb_msg.msg_iter, READ, to_read);
+	iov_iter_discard(&smb_msg.msg_iter, ITER_DEST, to_read);
 
 	return cifs_readv_from_socket(server, &smb_msg);
 }
···
 	struct msghdr smb_msg = {};
 	struct bio_vec bv = {
 		.bv_page = page, .bv_len = to_read, .bv_offset = page_offset};
-	iov_iter_bvec(&smb_msg.msg_iter, READ, &bv, 1, to_read);
+	iov_iter_bvec(&smb_msg.msg_iter, ITER_DEST, &bv, 1, to_read);
 	return cifs_readv_from_socket(server, &smb_msg);
 }
 

fs/cifs/file.c

···
 		ctx->iter = *from;
 		ctx->len = len;
 	} else {
-		rc = setup_aio_ctx_iter(ctx, from, WRITE);
+		rc = setup_aio_ctx_iter(ctx, from, ITER_SOURCE);
 		if (rc) {
 			kref_put(&ctx->refcount, cifs_aio_ctx_release);
 			return rc;
···
 		ctx->iter = *to;
 		ctx->len = len;
 	} else {
-		rc = setup_aio_ctx_iter(ctx, to, READ);
+		rc = setup_aio_ctx_iter(ctx, to, ITER_DEST);
 		if (rc) {
 			kref_put(&ctx->refcount, cifs_aio_ctx_release);
 			return rc;

fs/cifs/fscache.c

···
 	bvec[0].bv_page		= page;
 	bvec[0].bv_offset	= 0;
 	bvec[0].bv_len		= PAGE_SIZE;
-	iov_iter_bvec(&iter, READ, bvec, ARRAY_SIZE(bvec), PAGE_SIZE);
+	iov_iter_bvec(&iter, ITER_DEST, bvec, ARRAY_SIZE(bvec), PAGE_SIZE);
 
 	ret = fscache_begin_read_operation(&cres, cookie);
 	if (ret < 0)
···
 	bvec[0].bv_page		= page;
 	bvec[0].bv_offset	= 0;
 	bvec[0].bv_len		= PAGE_SIZE;
-	iov_iter_bvec(&iter, WRITE, bvec, ARRAY_SIZE(bvec), PAGE_SIZE);
+	iov_iter_bvec(&iter, ITER_SOURCE, bvec, ARRAY_SIZE(bvec), PAGE_SIZE);
 
 	ret = fscache_begin_write_operation(&cres, cookie);
 	if (ret < 0)

fs/cifs/smb2ops.c

···
 			return 0;
 		}
 
-		iov_iter_bvec(&iter, WRITE, bvec, npages, data_len);
+		iov_iter_bvec(&iter, ITER_SOURCE, bvec, npages, data_len);
 	} else if (buf_len >= data_offset + data_len) {
 		/* read response payload is in buf */
 		WARN_ONCE(npages > 0, "read data can be either in buf or in pages");
 		iov.iov_base = buf + data_offset;
 		iov.iov_len = data_len;
-		iov_iter_kvec(&iter, WRITE, &iov, 1, data_len);
+		iov_iter_kvec(&iter, ITER_SOURCE, &iov, 1, data_len);
 	} else {
 		/* read response payload cannot be in both buf and pages */
 		WARN_ONCE(1, "buf can not contain only a part of read data");

fs/cifs/transport.c

···
 			.iov_base = &rfc1002_marker,
 			.iov_len  = 4
 		};
-		iov_iter_kvec(&smb_msg.msg_iter, WRITE, &hiov, 1, 4);
+		iov_iter_kvec(&smb_msg.msg_iter, ITER_SOURCE, &hiov, 1, 4);
 		rc = smb_send_kvec(server, &smb_msg, &sent);
 		if (rc < 0)
 			goto unmask;
···
 			size += iov[i].iov_len;
 		}
 
-		iov_iter_kvec(&smb_msg.msg_iter, WRITE, iov, n_vec, size);
+		iov_iter_kvec(&smb_msg.msg_iter, ITER_SOURCE, iov, n_vec, size);
 
 		rc = smb_send_kvec(server, &smb_msg, &sent);
 		if (rc < 0)
···
 			rqst_page_get_length(&rqst[j], i, &bvec.bv_len,
 					     &bvec.bv_offset);
 
-			iov_iter_bvec(&smb_msg.msg_iter, WRITE,
+			iov_iter_bvec(&smb_msg.msg_iter, ITER_SOURCE,
 				      &bvec, 1, bvec.bv_len);
 			rc = smb_send_kvec(server, &smb_msg, &sent);
 			if (rc < 0)

fs/coredump.c

···
 	if (dump_interrupted())
 		return 0;
 	pos = file->f_pos;
-	iov_iter_bvec(&iter, WRITE, &bvec, 1, PAGE_SIZE);
+	iov_iter_bvec(&iter, ITER_SOURCE, &bvec, 1, PAGE_SIZE);
 	n = __kernel_write_iter(cprm->file, &iter, &pos);
 	if (n != PAGE_SIZE)
 		return 0;

fs/erofs/fscache.c

···
 
 		atomic_inc(&rreq->nr_outstanding);
 
-		iov_iter_xarray(&iter, READ, &rreq->mapping->i_pages,
+		iov_iter_xarray(&iter, ITER_DEST, &rreq->mapping->i_pages,
 				start + done, subreq->len);
 
 		ret = fscache_read(cres, subreq->start, &iter,
···
 		if (IS_ERR(src))
 			return PTR_ERR(src);
 
-		iov_iter_xarray(&iter, READ, &mapping->i_pages, pos, PAGE_SIZE);
+		iov_iter_xarray(&iter, ITER_DEST, &mapping->i_pages, pos, PAGE_SIZE);
 		if (copy_to_iter(src + offset, size, &iter) != size) {
 			erofs_put_metabuf(&buf);
 			return -EFAULT;
···
 
 	if (!(map.m_flags & EROFS_MAP_MAPPED)) {
 		count = len;
-		iov_iter_xarray(&iter, READ, &mapping->i_pages, pos, count);
+		iov_iter_xarray(&iter, ITER_DEST, &mapping->i_pages, pos, count);
 		iov_iter_zero(count, &iter);
 		return count;
 	}

fs/fscache/io.c

···
 	 * taken into account.
 	 */
 
-	iov_iter_xarray(&iter, WRITE, &mapping->i_pages, start, len);
+	iov_iter_xarray(&iter, ITER_SOURCE, &mapping->i_pages, start, len);
 	fscache_write(cres, start, &iter, fscache_wreq_done, wreq);
 	return;
 

fs/fuse/ioctl.c

···
 		ap.args.in_pages = true;
 
 		err = -EFAULT;
-		iov_iter_init(&ii, WRITE, in_iov, in_iovs, in_size);
+		iov_iter_init(&ii, ITER_SOURCE, in_iov, in_iovs, in_size);
 		for (i = 0; iov_iter_count(&ii) && !WARN_ON(i >= ap.num_pages); i++) {
 			c = copy_page_from_iter(ap.pages[i], 0, PAGE_SIZE, &ii);
 			if (c != PAGE_SIZE && iov_iter_count(&ii))
···
 		goto out;
 
 	err = -EFAULT;
-	iov_iter_init(&ii, READ, out_iov, out_iovs, transferred);
+	iov_iter_init(&ii, ITER_DEST, out_iov, out_iovs, transferred);
 	for (i = 0; iov_iter_count(&ii) && !WARN_ON(i >= ap.num_pages); i++) {
 		c = copy_page_to_iter(ap.pages[i], 0, PAGE_SIZE, &ii);
 		if (c != PAGE_SIZE && iov_iter_count(&ii))

fs/netfs/io.c

···
 {
 	struct iov_iter iter;
 
-	iov_iter_xarray(&iter, READ, &subreq->rreq->mapping->i_pages,
+	iov_iter_xarray(&iter, ITER_DEST, &subreq->rreq->mapping->i_pages,
 			subreq->start + subreq->transferred,
 			subreq->len   - subreq->transferred);
 	iov_iter_zero(iov_iter_count(&iter), &iter);
···
 	struct iov_iter iter;
 
 	netfs_stat(&netfs_n_rh_read);
-	iov_iter_xarray(&iter, READ, &rreq->mapping->i_pages,
+	iov_iter_xarray(&iter, ITER_DEST, &rreq->mapping->i_pages,
 			subreq->start + subreq->transferred,
 			subreq->len   - subreq->transferred);
 
···
 			continue;
 		}
 
-		iov_iter_xarray(&iter, WRITE, &rreq->mapping->i_pages,
+		iov_iter_xarray(&iter, ITER_SOURCE, &rreq->mapping->i_pages,
 				subreq->start, subreq->len);
 
 		atomic_inc(&rreq->nr_copy_ops);

fs/nfs/fscache.c

···
 	bvec[0].bv_page		= page;
 	bvec[0].bv_offset	= 0;
 	bvec[0].bv_len		= PAGE_SIZE;
-	iov_iter_bvec(&iter, READ, bvec, ARRAY_SIZE(bvec), PAGE_SIZE);
+	iov_iter_bvec(&iter, ITER_DEST, bvec, ARRAY_SIZE(bvec), PAGE_SIZE);
 
 	ret = fscache_begin_read_operation(&cres, cookie);
 	if (ret < 0)
···
 	bvec[0].bv_page		= page;
 	bvec[0].bv_offset	= 0;
 	bvec[0].bv_len		= PAGE_SIZE;
-	iov_iter_bvec(&iter, WRITE, bvec, ARRAY_SIZE(bvec), PAGE_SIZE);
+	iov_iter_bvec(&iter, ITER_SOURCE, bvec, ARRAY_SIZE(bvec), PAGE_SIZE);
 
 	ret = fscache_begin_write_operation(&cres, cookie);
 	if (ret < 0)

fs/nfsd/vfs.c

···
 	ssize_t host_err;
 
 	trace_nfsd_read_vector(rqstp, fhp, offset, *count);
-	iov_iter_kvec(&iter, READ, vec, vlen, *count);
+	iov_iter_kvec(&iter, ITER_DEST, vec, vlen, *count);
 	host_err = vfs_iter_read(file, &iter, &ppos, 0);
 	return nfsd_finish_read(rqstp, fhp, file, offset, count, eof, host_err);
 }
···
 	if (stable && !use_wgather)
 		flags |= RWF_SYNC;
 
-	iov_iter_kvec(&iter, WRITE, vec, vlen, *cnt);
+	iov_iter_kvec(&iter, ITER_SOURCE, vec, vlen, *cnt);
 	since = READ_ONCE(file->f_wb_err);
 	if (verf)
 		nfsd_copy_write_verifier(verf, nn);

fs/ocfs2/cluster/tcp.c

···
 {
 	struct kvec vec = { .iov_len = len, .iov_base = data, };
 	struct msghdr msg = { .msg_flags = MSG_DONTWAIT, };
-	iov_iter_kvec(&msg.msg_iter, READ, &vec, 1, len);
+	iov_iter_kvec(&msg.msg_iter, ITER_DEST, &vec, 1, len);
 	return sock_recvmsg(sock, &msg, MSG_DONTWAIT);
 }
 

fs/orangefs/inode.c

···
 	bv.bv_len = wlen;
 	bv.bv_offset = off % PAGE_SIZE;
 	WARN_ON(wlen == 0);
-	iov_iter_bvec(&iter, WRITE, &bv, 1, wlen);
+	iov_iter_bvec(&iter, ITER_SOURCE, &bv, 1, wlen);
 
 	ret = wait_for_direct_io(ORANGEFS_IO_WRITE, inode, &off, &iter, wlen,
 	    len, wr, NULL, NULL);
···
 		else
 			ow->bv[i].bv_offset = 0;
 	}
-	iov_iter_bvec(&iter, WRITE, ow->bv, ow->npages, ow->len);
+	iov_iter_bvec(&iter, ITER_SOURCE, ow->bv, ow->npages, ow->len);
 
 	WARN_ON(ow->off >= len);
 	if (ow->off + ow->len > len)
···
 	offset = readahead_pos(rac);
 	i_pages = &rac->mapping->i_pages;
 
-	iov_iter_xarray(&iter, READ, i_pages, offset, readahead_length(rac));
+	iov_iter_xarray(&iter, ITER_DEST, i_pages, offset, readahead_length(rac));
 
 	/* read in the pages. */
 	if ((ret = wait_for_direct_io(ORANGEFS_IO_READ, inode,
···
 	bv.bv_page = &folio->page;
 	bv.bv_len = folio_size(folio);
 	bv.bv_offset = 0;
-	iov_iter_bvec(&iter, READ, &bv, 1, folio_size(folio));
+	iov_iter_bvec(&iter, ITER_DEST, &bv, 1, folio_size(folio));
 
 	ret = wait_for_direct_io(ORANGEFS_IO_READ, inode, &off, &iter,
 			folio_size(folio), inode->i_size, NULL, NULL, file);

fs/proc/vmcore.c

···
 	struct kvec kvec = { .iov_base = buf, .iov_len = count };
 	struct iov_iter iter;
 
-	iov_iter_kvec(&iter, READ, &kvec, 1, count);
+	iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, count);
 
 	return read_from_oldmem(&iter, count, ppos, false);
 }
···
 	struct kvec kvec = { .iov_base = buf, .iov_len = count };
 	struct iov_iter iter;
 
-	iov_iter_kvec(&iter, READ, &kvec, 1, count);
+	iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, count);
 
 	return read_from_oldmem(&iter, count, ppos,
 			cc_platform_has(CC_ATTR_MEM_ENCRYPT));
···
 		offset = (loff_t) index << PAGE_SHIFT;
 		kvec.iov_base = page_address(page);
 		kvec.iov_len = PAGE_SIZE;
-		iov_iter_kvec(&iter, READ, &kvec, 1, PAGE_SIZE);
+		iov_iter_kvec(&iter, ITER_DEST, &kvec, 1, PAGE_SIZE);
 
 		rc = __read_vmcore(&iter, &offset);
 		if (rc < 0) {

fs/read_write.c

···
 
 	init_sync_kiocb(&kiocb, filp);
 	kiocb.ki_pos = (ppos ? *ppos : 0);
-	iov_iter_ubuf(&iter, READ, buf, len);
+	iov_iter_ubuf(&iter, ITER_DEST, buf, len);
 
 	ret = call_read_iter(filp, &kiocb, &iter);
 	BUG_ON(ret == -EIOCBQUEUED);
···
 
 	init_sync_kiocb(&kiocb, file);
 	kiocb.ki_pos = pos ? *pos : 0;
-	iov_iter_kvec(&iter, READ, &iov, 1, iov.iov_len);
+	iov_iter_kvec(&iter, ITER_DEST, &iov, 1, iov.iov_len);
 	ret = file->f_op->read_iter(&kiocb, &iter);
 	if (ret > 0) {
 		if (pos)
···
 
 	init_sync_kiocb(&kiocb, filp);
 	kiocb.ki_pos = (ppos ? *ppos : 0);
-	iov_iter_ubuf(&iter, WRITE, (void __user *)buf, len);
+	iov_iter_ubuf(&iter, ITER_SOURCE, (void __user *)buf, len);
 
 	ret = call_write_iter(filp, &kiocb, &iter);
 	BUG_ON(ret == -EIOCBQUEUED);
···
 		.iov_len	= min_t(size_t, count, MAX_RW_COUNT),
 	};
 	struct iov_iter iter;
-	iov_iter_kvec(&iter, WRITE, &iov, 1, iov.iov_len);
+	iov_iter_kvec(&iter, ITER_SOURCE, &iov, 1, iov.iov_len);
 	return __kernel_write_iter(file, &iter, pos);
 }
 /*
···
 	struct iov_iter iter;
 	ssize_t ret;
 
-	ret = import_iovec(READ, vec, vlen, ARRAY_SIZE(iovstack), &iov, &iter);
+	ret = import_iovec(ITER_DEST, vec, vlen, ARRAY_SIZE(iovstack), &iov, &iter);
 	if (ret >= 0) {
 		ret = do_iter_read(file, &iter, pos, flags);
 		kfree(iov);
···
 	struct iov_iter iter;
 	ssize_t ret;
 
-	ret = import_iovec(WRITE, vec, vlen, ARRAY_SIZE(iovstack), &iov, &iter);
+	ret = import_iovec(ITER_SOURCE, vec, vlen, ARRAY_SIZE(iovstack), &iov, &iter);
 	if (ret >= 0) {
 		file_start_write(file);
 		ret = do_iter_write(file, &iter, pos, flags);

fs/seq_file.c

···
 	ssize_t ret;
 
 	init_sync_kiocb(&kiocb, file);
-	iov_iter_init(&iter, READ, &iov, 1, size);
+	iov_iter_init(&iter, ITER_DEST, &iov, 1, size);
 
 	kiocb.ki_pos = *ppos;
 	ret = seq_read_iter(&kiocb, &iter);

fs/splice.c

···
 	struct kiocb kiocb;
 	int ret;
 
-	iov_iter_pipe(&to, READ, pipe, len);
+	iov_iter_pipe(&to, ITER_DEST, pipe, len);
 	init_sync_kiocb(&kiocb, in);
 	kiocb.ki_pos = *ppos;
 	ret = call_read_iter(in, &kiocb, &to);
···
 			n++;
 		}
 
-		iov_iter_bvec(&from, WRITE, array, n, sd.total_len - left);
+		iov_iter_bvec(&from, ITER_SOURCE, array, n, sd.total_len - left);
 		ret = vfs_iter_write(out, &from, &sd.pos, 0);
 		if (ret <= 0)
 			break;
···
 	if (!f.file)
 		return -EBADF;
 	if (f.file->f_mode & FMODE_WRITE) {
-		*type = WRITE;
+		*type = ITER_SOURCE;
 	} else if (f.file->f_mode & FMODE_READ) {
-		*type = READ;
+		*type = ITER_DEST;
 	} else {
 		fdput(f);
 		return -EBADF;
···
 
 	if (!iov_iter_count(&iter))
 		error = 0;
-	else if (iov_iter_rw(&iter) == WRITE)
+	else if (type == ITER_SOURCE)
 		error = vmsplice_to_pipe(f.file, &iter, flags);
 	else
 		error = vmsplice_to_user(f.file, &iter, flags);

include/linux/uio.h

···
 	ITER_UBUF,
 };
 
+#define ITER_SOURCE	1	// == WRITE
+#define ITER_DEST	0	// == READ
+
 struct iov_iter_state {
 	size_t iov_offset;
 	size_t count;

io_uring/net.c

···
 	if (unlikely(!sock))
 		return -ENOTSOCK;
 
-	ret = import_single_range(WRITE, sr->buf, sr->len, &iov, &msg.msg_iter);
+	ret = import_single_range(ITER_SOURCE, sr->buf, sr->len, &iov, &msg.msg_iter);
 	if (unlikely(ret))
 		return ret;
 
···
 		}
 	} else {
 		iomsg->free_iov = iomsg->fast_iov;
-		ret = __import_iovec(READ, msg.msg_iov, msg.msg_iovlen, UIO_FASTIOV,
+		ret = __import_iovec(ITER_DEST, msg.msg_iov, msg.msg_iovlen, UIO_FASTIOV,
 				     &iomsg->free_iov, &iomsg->msg.msg_iter,
 				     false);
 		if (ret > 0)
···
 		}
 	} else {
 		iomsg->free_iov = iomsg->fast_iov;
-		ret = __import_iovec(READ, (struct iovec __user *)uiov, msg.msg_iovlen,
+		ret = __import_iovec(ITER_DEST, (struct iovec __user *)uiov, msg.msg_iovlen,
 				   UIO_FASTIOV, &iomsg->free_iov,
 				   &iomsg->msg.msg_iter, true);
 		if (ret < 0)
···
 
 		kmsg->fast_iov[0].iov_base = buf;
 		kmsg->fast_iov[0].iov_len = len;
-		iov_iter_init(&kmsg->msg.msg_iter, READ, kmsg->fast_iov, 1,
+		iov_iter_init(&kmsg->msg.msg_iter, ITER_DEST, kmsg->fast_iov, 1,
 				len);
 	}
 
···
 		sr->buf = buf;
 	}
 
-	ret = import_single_range(READ, sr->buf, len, &iov, &msg.msg_iter);
+	ret = import_single_range(ITER_DEST, sr->buf, len, &iov, &msg.msg_iter);
 	if (unlikely(ret))
 		goto out_free;
 
···
 		return io_setup_async_addr(req, &__address, issue_flags);
 
 	if (zc->flags & IORING_RECVSEND_FIXED_BUF) {
-		ret = io_import_fixed(WRITE, &msg.msg_iter, req->imu,
+		ret = io_import_fixed(ITER_SOURCE, &msg.msg_iter, req->imu,
 					(u64)(uintptr_t)zc->buf, zc->len);
 		if (unlikely(ret))
 			return ret;
 		msg.sg_from_iter = io_sg_from_iter;
 	} else {
-		ret = import_single_range(WRITE, zc->buf, zc->len, &iov,
+		ret = import_single_range(ITER_SOURCE, zc->buf, zc->len, &iov,
 					  &msg.msg_iter);
 		if (unlikely(ret))
 			return ret;

io_uring/rw.c

···
 
 int io_readv_prep_async(struct io_kiocb *req)
 {
-	return io_rw_prep_async(req, READ);
+	return io_rw_prep_async(req, ITER_DEST);
 }
 
 int io_writev_prep_async(struct io_kiocb *req)
 {
-	return io_rw_prep_async(req, WRITE);
+	return io_rw_prep_async(req, ITER_SOURCE);
 }
 
 /*
···
 	loff_t *ppos;
 
 	if (!req_has_async_data(req)) {
-		ret = io_import_iovec(READ, req, &iovec, s, issue_flags);
+		ret = io_import_iovec(ITER_DEST, req, &iovec, s, issue_flags);
 		if (unlikely(ret < 0))
 			return ret;
 	} else {
···
 		 * buffers, as we dropped the selected one before retry.
 		 */
 		if (io_do_buffer_select(req)) {
-			ret = io_import_iovec(READ, req, &iovec, s, issue_flags);
+			ret = io_import_iovec(ITER_DEST, req, &iovec, s, issue_flags);
 			if (unlikely(ret < 0))
 				return ret;
 		}
···
 	loff_t *ppos;
 
 	if (!req_has_async_data(req)) {
-		ret = io_import_iovec(WRITE, req, &iovec, s, issue_flags);
+		ret = io_import_iovec(ITER_SOURCE, req, &iovec, s, issue_flags);
 		if (unlikely(ret < 0))
 			return ret;
 	} else {

kernel/trace/trace_events_user.c

···
 	if (unlikely(*ppos != 0))
 		return -EFAULT;
 
-	if (unlikely(import_single_range(WRITE, (char __user *)ubuf,
+	if (unlikely(import_single_range(ITER_SOURCE, (char __user *)ubuf,
 					 count, &iov, &i)))
 		return -EFAULT;
 

mm/madvise.c

···
 		goto out;
 	}
 
-	ret = import_iovec(READ, vec, vlen, ARRAY_SIZE(iovstack), &iov, &iter);
+	ret = import_iovec(ITER_DEST, vec, vlen, ARRAY_SIZE(iovstack), &iov, &iter);
 	if (ret < 0)
 		goto out;
 

mm/page_io.c

···
 	struct address_space *mapping = sio->iocb.ki_filp->f_mapping;
 	int ret;
 
-	iov_iter_bvec(&from, WRITE, sio->bvec, sio->pages, sio->len);
+	iov_iter_bvec(&from, ITER_SOURCE, sio->bvec, sio->pages, sio->len);
 	ret = mapping->a_ops->swap_rw(&sio->iocb, &from);
 	if (ret != -EIOCBQUEUED)
 		sio_write_complete(&sio->iocb, ret);
···
 	struct address_space *mapping = sio->iocb.ki_filp->f_mapping;
 	int ret;
 
-	iov_iter_bvec(&from, READ, sio->bvec, sio->pages, sio->len);
+	iov_iter_bvec(&from, ITER_DEST, sio->bvec, sio->pages, sio->len);
 	ret = mapping->a_ops->swap_rw(&sio->iocb, &from);
 	if (ret != -EIOCBQUEUED)
 		sio_read_complete(&sio->iocb, ret);

mm/process_vm_access.c

···
 	struct iovec *iov_r;
 	struct iov_iter iter;
 	ssize_t rc;
-	int dir = vm_write ? WRITE : READ;
+	int dir = vm_write ? ITER_SOURCE : ITER_DEST;
 
 	if (flags != 0)
 		return -EINVAL;

net/9p/client.c

···
 	struct kvec kv = {.iov_base = data, .iov_len = count};
 	struct iov_iter to;
 
-	iov_iter_kvec(&to, READ, &kv, 1, count);
+	iov_iter_kvec(&to, ITER_DEST, &kv, 1, count);
 
 	p9_debug(P9_DEBUG_9P, ">>> TREADDIR fid %d offset %llu count %d\n",
 		 fid->fid, offset, count);

net/bluetooth/6lowpan.c

···
 	iv.iov_len = skb->len;
 
 	memset(&msg, 0, sizeof(msg));
-	iov_iter_kvec(&msg.msg_iter, WRITE, &iv, 1, skb->len);
+	iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, &iv, 1, skb->len);
 
 	err = l2cap_chan_send(chan, &msg, skb->len);
 	if (err > 0) {

net/bluetooth/a2mp.c

···
 
 	memset(&msg, 0, sizeof(msg));
 
-	iov_iter_kvec(&msg.msg_iter, WRITE, &iv, 1, total_len);
+	iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, &iv, 1, total_len);
 
 	l2cap_chan_send(chan, &msg, total_len);
 

net/bluetooth/smp.c

···
 
 	memset(&msg, 0, sizeof(msg));
 
-	iov_iter_kvec(&msg.msg_iter, WRITE, iv, 2, 1 + len);
+	iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, iv, 2, 1 + len);
 
 	l2cap_chan_send(chan, &msg, 1 + len);
 

net/ceph/messenger_v1.c

···
 	if (!buf)
 		msg.msg_flags |= MSG_TRUNC;
 
-	iov_iter_kvec(&msg.msg_iter, READ, &iov, 1, len);
+	iov_iter_kvec(&msg.msg_iter, ITER_DEST, &iov, 1, len);
 	r = sock_recvmsg(sock, &msg, msg.msg_flags);
 	if (r == -EAGAIN)
 		r = 0;
···
 	int r;
 
 	BUG_ON(page_offset + length > PAGE_SIZE);
-	iov_iter_bvec(&msg.msg_iter, READ, &bvec, 1, length);
+	iov_iter_bvec(&msg.msg_iter, ITER_DEST, &bvec, 1, length);
 	r = sock_recvmsg(sock, &msg, msg.msg_flags);
 	if (r == -EAGAIN)
 		r = 0;

net/ceph/messenger_v2.c

···
 						  bv.bv_offset, bv.bv_len,
 						  CEPH_MSG_FLAGS);
 		} else {
-			iov_iter_bvec(&msg.msg_iter, WRITE, &bv, 1, bv.bv_len);
+			iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bv, 1, bv.bv_len);
 			ret = sock_sendmsg(sock, &msg);
 		}
 		if (ret <= 0) {
···
 	WARN_ON(iov_iter_count(&con->v2.in_iter));
 
 	con->v2.in_kvec_cnt = 0;
-	iov_iter_kvec(&con->v2.in_iter, READ, con->v2.in_kvecs, 0, 0);
+	iov_iter_kvec(&con->v2.in_iter, ITER_DEST, con->v2.in_kvecs, 0, 0);
 }
 
 static void set_in_bvec(struct ceph_connection *con, const struct bio_vec *bv)
···
 	WARN_ON(iov_iter_count(&con->v2.in_iter));
 
 	con->v2.in_bvec = *bv;
-	iov_iter_bvec(&con->v2.in_iter, READ, &con->v2.in_bvec, 1, bv->bv_len);
+	iov_iter_bvec(&con->v2.in_iter, ITER_DEST, &con->v2.in_bvec, 1, bv->bv_len);
 }
 
 static void set_in_skip(struct ceph_connection *con, int len)
···
 	WARN_ON(iov_iter_count(&con->v2.in_iter));
 
 	dout("%s con %p len %d\n", __func__, con, len);
-	iov_iter_discard(&con->v2.in_iter, READ, len);
+	iov_iter_discard(&con->v2.in_iter, ITER_DEST, len);
 }
 
 static void add_out_kvec(struct ceph_connection *con, void *buf, int len)
···
 
 	con->v2.out_kvec_cnt = 0;
 
-	iov_iter_kvec(&con->v2.out_iter, WRITE, con->v2.out_kvecs, 0, 0);
+	iov_iter_kvec(&con->v2.out_iter, ITER_SOURCE, con->v2.out_kvecs, 0, 0);
 	con->v2.out_iter_sendpage = false;
 }
 
···
 
 	con->v2.out_bvec = *bv;
 	con->v2.out_iter_sendpage = zerocopy;
-	iov_iter_bvec(&con->v2.out_iter, WRITE, &con->v2.out_bvec, 1,
+	iov_iter_bvec(&con->v2.out_iter, ITER_SOURCE, &con->v2.out_bvec, 1,
 		      con->v2.out_bvec.bv_len);
 }
 
···
 	con->v2.out_bvec.bv_offset = 0;
 	con->v2.out_bvec.bv_len = min(con->v2.out_zero, (int)PAGE_SIZE);
 	con->v2.out_iter_sendpage = true;
-	iov_iter_bvec(&con->v2.out_iter, WRITE, &con->v2.out_bvec, 1,
+	iov_iter_bvec(&con->v2.out_iter, ITER_SOURCE, &con->v2.out_bvec, 1,
 		      con->v2.out_bvec.bv_len);
 }
 

net/compat.c

···
 	if (err)
 		return err;
 
-	err = import_iovec(save_addr ? READ : WRITE, compat_ptr(msg.msg_iov), msg.msg_iovlen,
+	err = import_iovec(save_addr ? ITER_DEST : ITER_SOURCE,
+			   compat_ptr(msg.msg_iov), msg.msg_iovlen,
 			   UIO_FASTIOV, iov, &kmsg->msg_iter);
 	return err < 0 ? err : 0;
 }

net/ipv4/tcp.c

···
 	if (copy_address != zc->copybuf_address)
 		return -EINVAL;
 
-	err = import_single_range(READ, (void __user *)copy_address,
+	err = import_single_range(ITER_DEST, (void __user *)copy_address,
 				  inq, &iov, &msg.msg_iter);
 	if (err)
 		return err;
···
 	if (copy_address != zc->copybuf_address)
 		return -EINVAL;
 
-	err = import_single_range(READ, (void __user *)copy_address,
+	err = import_single_range(ITER_DEST, (void __user *)copy_address,
 				  copylen, &iov, &msg.msg_iter);
 	if (err)
 		return err;

net/netfilter/ipvs/ip_vs_sync.c

···
 	EnterFunction(7);
 
 	/* Receive a packet */
-	iov_iter_kvec(&msg.msg_iter, READ, &iov, 1, buflen);
+	iov_iter_kvec(&msg.msg_iter, ITER_DEST, &iov, 1, buflen);
 	len = sock_recvmsg(sock, &msg, MSG_DONTWAIT);
 	if (len < 0)
 		return len;

net/smc/smc_clc.c

···
 	 */
 	krflags = MSG_PEEK | MSG_WAITALL;
 	clc_sk->sk_rcvtimeo = timeout;
-	iov_iter_kvec(&msg.msg_iter, READ, &vec, 1,
+	iov_iter_kvec(&msg.msg_iter, ITER_DEST, &vec, 1,
 			sizeof(struct smc_clc_msg_hdr));
 	len = sock_recvmsg(smc->clcsock, &msg, krflags);
 	if (signal_pending(current)) {
···
 	} else {
 		recvlen = datlen;
 	}
-	iov_iter_kvec(&msg.msg_iter, READ, &vec, 1, recvlen);
+	iov_iter_kvec(&msg.msg_iter, ITER_DEST, &vec, 1, recvlen);
 	krflags = MSG_WAITALL;
 	len = sock_recvmsg(smc->clcsock, &msg, krflags);
 	if (len < recvlen || !smc_clc_msg_hdr_valid(clcm, check_trl)) {
···
 		/* receive remaining proposal message */
 		recvlen = datlen > SMC_CLC_RECV_BUF_LEN ?
 						SMC_CLC_RECV_BUF_LEN : datlen;
-		iov_iter_kvec(&msg.msg_iter, READ, &vec, 1, recvlen);
+		iov_iter_kvec(&msg.msg_iter, ITER_DEST, &vec, 1, recvlen);
 		len = sock_recvmsg(smc->clcsock, &msg, krflags);
 		datlen -= len;
 	}

net/smc/smc_tx.c

···
 
 	iov.iov_base = kaddr + offset;
 	iov.iov_len = size;
-	iov_iter_kvec(&msg.msg_iter, WRITE, &iov, 1, size);
+	iov_iter_kvec(&msg.msg_iter, ITER_SOURCE, &iov, 1, size);
 	rc = smc_tx_sendmsg(smc, &msg, size);
 	kunmap(page);
 	return rc;

net/socket.c

···
 int kernel_sendmsg(struct socket *sock, struct msghdr *msg,
 		   struct kvec *vec, size_t num, size_t size)
 {
-	iov_iter_kvec(&msg->msg_iter, WRITE, vec, num, size);
+	iov_iter_kvec(&msg->msg_iter, ITER_SOURCE, vec, num, size);
 	return sock_sendmsg(sock, msg);
 }
 EXPORT_SYMBOL(kernel_sendmsg);
···
 	if (!sock->ops->sendmsg_locked)
 		return sock_no_sendmsg_locked(sk, msg, size);
 
-	iov_iter_kvec(&msg->msg_iter, WRITE, vec, num, size);
+	iov_iter_kvec(&msg->msg_iter, ITER_SOURCE, vec, num, size);
 
 	return sock->ops->sendmsg_locked(sk, msg, msg_data_left(msg));
 }
···
 		   struct kvec *vec, size_t num, size_t size, int flags)
 {
 	msg->msg_control_is_user = false;
-	iov_iter_kvec(&msg->msg_iter, READ, vec, num, size);
+	iov_iter_kvec(&msg->msg_iter, ITER_DEST, vec, num, size);
 	return sock_recvmsg(sock, msg, flags);
 }
 EXPORT_SYMBOL(kernel_recvmsg);
···
 	struct iovec iov;
 	int fput_needed;
 
-	err = import_single_range(WRITE, buff, len, &iov, &msg.msg_iter);
+	err = import_single_range(ITER_SOURCE, buff, len, &iov, &msg.msg_iter);
 	if (unlikely(err))
 		return err;
 	sock = sockfd_lookup_light(fd, &err, &fput_needed);
···
 	int err, err2;
 	int fput_needed;
 
-	err = import_single_range(READ, ubuf, size, &iov, &msg.msg_iter);
+	err = import_single_range(ITER_DEST, ubuf, size, &iov, &msg.msg_iter);
 	if (unlikely(err))
 		return err;
 	sock = sockfd_lookup_light(fd, &err, &fput_needed);
···
 	if (err)
 		return err;
 
-	err = import_iovec(save_addr ? READ : WRITE,
+	err = import_iovec(save_addr ? ITER_DEST : ITER_SOURCE,
 			    msg.msg_iov, msg.msg_iovlen,
 			    UIO_FASTIOV, iov, &kmsg->msg_iter);
 	return err < 0 ? err : 0;

net/sunrpc/socklib.c

···
 static int xprt_send_kvec(struct socket *sock, struct msghdr *msg,
 			  struct kvec *vec, size_t seek)
 {
-	iov_iter_kvec(&msg->msg_iter, WRITE, vec, 1, vec->iov_len);
+	iov_iter_kvec(&msg->msg_iter, ITER_SOURCE, vec, 1, vec->iov_len);
 	return xprt_sendmsg(sock, msg, seek);
 }
 
 static int xprt_send_pagedata(struct socket *sock, struct msghdr *msg,
 			      struct xdr_buf *xdr, size_t base)
 {
-	iov_iter_bvec(&msg->msg_iter, WRITE, xdr->bvec, xdr_buf_pagecount(xdr),
+	iov_iter_bvec(&msg->msg_iter, ITER_SOURCE, xdr->bvec, xdr_buf_pagecount(xdr),
 		      xdr->page_len + xdr->page_base);
 	return xprt_sendmsg(sock, msg, base + xdr->page_base);
 }
···
 	};
 	size_t len = iov[0].iov_len + iov[1].iov_len;
 
-	iov_iter_kvec(&msg->msg_iter, WRITE, iov, 2, len);
+	iov_iter_kvec(&msg->msg_iter, ITER_SOURCE, iov, 2, len);
 	return xprt_sendmsg(sock, msg, base);
 }
 

net/sunrpc/svcsock.c

···
 	rqstp->rq_respages = &rqstp->rq_pages[i];
 	rqstp->rq_next_page = rqstp->rq_respages + 1;
 
-	iov_iter_bvec(&msg.msg_iter, READ, bvec, i, buflen);
+	iov_iter_bvec(&msg.msg_iter, ITER_DEST, bvec, i, buflen);
 	if (seek) {
 		iov_iter_advance(&msg.msg_iter, seek);
 		buflen -= seek;
···
 		want = sizeof(rpc_fraghdr) - svsk->sk_tcplen;
 		iov.iov_base = ((char *)&svsk->sk_marker) + svsk->sk_tcplen;
 		iov.iov_len  = want;
-		iov_iter_kvec(&msg.msg_iter, READ, &iov, 1, want);
+		iov_iter_kvec(&msg.msg_iter, ITER_DEST, &iov, 1, want);
 		len = sock_recvmsg(svsk->sk_sock, &msg, MSG_DONTWAIT);
 		if (len < 0)
 			return len;

net/sunrpc/xprtsock.c

···
 xs_read_kvec(struct socket *sock, struct msghdr *msg, int flags,
 		struct kvec *kvec, size_t count, size_t seek)
 {
-	iov_iter_kvec(&msg->msg_iter, READ, kvec, 1, count);
+	iov_iter_kvec(&msg->msg_iter, ITER_DEST, kvec, 1, count);
 	return xs_sock_recvmsg(sock, msg, flags, seek);
 }
 
···
 		struct bio_vec *bvec, unsigned long nr, size_t count,
 		size_t seek)
 {
-	iov_iter_bvec(&msg->msg_iter, READ, bvec, nr, count);
+	iov_iter_bvec(&msg->msg_iter, ITER_DEST, bvec, nr, count);
 	return xs_sock_recvmsg(sock, msg, flags, seek);
 }
 
···
 xs_read_discard(struct socket *sock, struct msghdr *msg, int flags,
 		size_t count)
 {
-	iov_iter_discard(&msg->msg_iter, READ, count);
+	iov_iter_discard(&msg->msg_iter, ITER_DEST, count);
 	return sock_recvmsg(sock, msg, flags);
 }
 

net/tipc/topsrv.c

···
 	iov.iov_base = &s;
 	iov.iov_len = sizeof(s);
 	msg.msg_name = NULL;
-	iov_iter_kvec(&msg.msg_iter, READ, &iov, 1, iov.iov_len);
+	iov_iter_kvec(&msg.msg_iter, ITER_DEST, &iov, 1, iov.iov_len);
 	ret = sock_recvmsg(con->sock, &msg, MSG_DONTWAIT);
 	if (ret == -EWOULDBLOCK)
 		return -EWOULDBLOCK;

net/tls/tls_device.c

···
 	kaddr = kmap(page);
 	iov.iov_base = kaddr + offset;
 	iov.iov_len = size;
-	iov_iter_kvec(&msg_iter, WRITE, &iov, 1, size);
+	iov_iter_kvec(&msg_iter, ITER_SOURCE, &iov, 1, size);
 	iter_offset.msg_iter = &msg_iter;
 	rc = tls_push_data(sk, iter_offset, size, flags, TLS_RECORD_TYPE_DATA,
 			   NULL);
···
 	union tls_iter_offset iter;
 	struct iov_iter msg_iter;
 
-	iov_iter_kvec(&msg_iter, WRITE, NULL, 0, 0);
+	iov_iter_kvec(&msg_iter, ITER_SOURCE, NULL, 0, 0);
 	iter.msg_iter = &msg_iter;
 	return tls_push_data(sk, iter, 0, flags, TLS_RECORD_TYPE_DATA, NULL);
 }

net/xfrm/espintcp.c

···
 	*((__be16 *)buf) = cpu_to_be16(msglen);
 	pfx_iov.iov_base = buf;
 	pfx_iov.iov_len = sizeof(buf);
-	iov_iter_kvec(&pfx_iter, WRITE, &pfx_iov, 1, pfx_iov.iov_len);
+	iov_iter_kvec(&pfx_iter, ITER_SOURCE, &pfx_iov, 1, pfx_iov.iov_len);
 
 	err = sk_msg_memcopy_from_iter(sk, &pfx_iter, &emsg->skmsg,
 				       pfx_iov.iov_len);

security/keys/keyctl.c

···
 		struct iov_iter from;
 		int ret;
 
-		ret = import_single_range(WRITE, (void __user *)_payload, plen,
+		ret = import_single_range(ITER_SOURCE, (void __user *)_payload, plen,
 					  &iov, &from);
 		if (unlikely(ret))
 			return ret;
···
 	if (!_payload_iov)
 		ioc = 0;
 
-	ret = import_iovec(WRITE, _payload_iov, ioc,
+	ret = import_iovec(ITER_SOURCE, _payload_iov, ioc,
 				    ARRAY_SIZE(iovstack), &iov, &from);
 	if (ret < 0)
 		return ret;