put iov_iter into msghdr

Note that the code _using_ ->msg_iter at that point will be very
unhappy with anything other than unshifted iovec-backed iov_iter.
We still need to convert users to proper primitives.

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

33 files changed, 90 insertions, 112 deletions

diff --git a/crypto/algif_hash.c b/crypto/algif_hash.c
index 35c93ff11f35..83cd2cc49c9f 100644
--- a/crypto/algif_hash.c
+++ b/crypto/algif_hash.c
@@ -42,7 +42,7 @@ static int hash_sendmsg(struct kiocb *unused, struct socket *sock,
         struct alg_sock *ask = alg_sk(sk);
         struct hash_ctx *ctx = ask->private;
         unsigned long iovlen;
-        struct iovec *iov;
+        const struct iovec *iov;
         long copied = 0;
         int err;
 
@@ -58,7 +58,7 @@ static int hash_sendmsg(struct kiocb *unused, struct socket *sock,
 
         ctx->more = 0;
 
-        for (iov = msg->msg_iov, iovlen = msg->msg_iovlen; iovlen > 0;
+        for (iov = msg->msg_iter.iov, iovlen = msg->msg_iter.nr_segs; iovlen > 0;
              iovlen--, iov++) {
                 unsigned long seglen = iov->iov_len;
                 char __user *from = iov->iov_base;
diff --git a/crypto/algif_skcipher.c b/crypto/algif_skcipher.c
index c3b482bee208..4f45dab24648 100644
--- a/crypto/algif_skcipher.c
+++ b/crypto/algif_skcipher.c
@@ -429,13 +429,13 @@ static int skcipher_recvmsg(struct kiocb *unused, struct socket *sock,
         struct skcipher_sg_list *sgl;
         struct scatterlist *sg;
         unsigned long iovlen;
-        struct iovec *iov;
+        const struct iovec *iov;
         int err = -EAGAIN;
         int used;
         long copied = 0;
 
         lock_sock(sk);
-        for (iov = msg->msg_iov, iovlen = msg->msg_iovlen; iovlen > 0;
+        for (iov = msg->msg_iter.iov, iovlen = msg->msg_iter.nr_segs; iovlen > 0;
              iovlen--, iov++) {
                 unsigned long seglen = iov->iov_len;
                 char __user *from = iov->iov_base;
diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index ba1e5db2152e..2c157cced81f 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -1095,9 +1095,7 @@ static int macvtap_sendmsg(struct kiocb *iocb, struct socket *sock,
                            struct msghdr *m, size_t total_len)
 {
         struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock);
-        struct iov_iter from;
-        iov_iter_init(&from, WRITE, m->msg_iov, m->msg_iovlen, total_len);
-        return macvtap_get_user(q, m, &from, m->msg_flags & MSG_DONTWAIT);
+        return macvtap_get_user(q, m, &m->msg_iter, m->msg_flags & MSG_DONTWAIT);
 }
 
 static int macvtap_recvmsg(struct kiocb *iocb, struct socket *sock,
@@ -1105,12 +1103,10 @@ static int macvtap_recvmsg(struct kiocb *iocb, struct socket *sock,
                            int flags)
 {
         struct macvtap_queue *q = container_of(sock, struct macvtap_queue, sock);
-        struct iov_iter to;
         int ret;
         if (flags & ~(MSG_DONTWAIT|MSG_TRUNC))
                 return -EINVAL;
-        iov_iter_init(&to, READ, m->msg_iov, m->msg_iovlen, total_len);
-        ret = macvtap_do_read(q, &to, flags & MSG_DONTWAIT);
+        ret = macvtap_do_read(q, &m->msg_iter, flags & MSG_DONTWAIT);
         if (ret > total_len) {
                 m->msg_flags |= MSG_TRUNC;
                 ret = flags & MSG_TRUNC ? ret : total_len;
diff --git a/drivers/net/tun.c b/drivers/net/tun.c
index 9c58286b8a42..f3e992ed87ac 100644
--- a/drivers/net/tun.c
+++ b/drivers/net/tun.c
@@ -1449,13 +1449,11 @@ static int tun_sendmsg(struct kiocb *iocb, struct socket *sock,
         int ret;
         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
         struct tun_struct *tun = __tun_get(tfile);
-        struct iov_iter from;
 
         if (!tun)
                 return -EBADFD;
 
-        iov_iter_init(&from, WRITE, m->msg_iov, m->msg_iovlen, total_len);
-        ret = tun_get_user(tun, tfile, m->msg_control, &from,
+        ret = tun_get_user(tun, tfile, m->msg_control, &m->msg_iter,
                            m->msg_flags & MSG_DONTWAIT);
         tun_put(tun);
         return ret;
@@ -1467,7 +1465,6 @@ static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
 {
         struct tun_file *tfile = container_of(sock, struct tun_file, socket);
         struct tun_struct *tun = __tun_get(tfile);
-        struct iov_iter to;
         int ret;
 
         if (!tun)
@@ -1482,8 +1479,7 @@ static int tun_recvmsg(struct kiocb *iocb, struct socket *sock,
                                          SOL_PACKET, TUN_TX_TIMESTAMP);
                 goto out;
         }
-        iov_iter_init(&to, READ, m->msg_iov, m->msg_iovlen, total_len);
-        ret = tun_do_read(tun, tfile, &to, flags & MSG_DONTWAIT);
+        ret = tun_do_read(tun, tfile, &m->msg_iter, flags & MSG_DONTWAIT);
         if (ret > total_len) {
                 m->msg_flags |= MSG_TRUNC;
                 ret = flags & MSG_TRUNC ? ret : total_len;
diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c
index 8dae2f724a35..9f06e70a2631 100644
--- a/drivers/vhost/net.c
+++ b/drivers/vhost/net.c
@@ -342,7 +342,6 @@ static void handle_tx(struct vhost_net *net)
                 .msg_namelen = 0,
                 .msg_control = NULL,
                 .msg_controllen = 0,
-                .msg_iov = vq->iov,
                 .msg_flags = MSG_DONTWAIT,
         };
         size_t len, total_len = 0;
@@ -396,8 +395,8 @@ static void handle_tx(struct vhost_net *net)
                 }
                 /* Skip header. TODO: support TSO. */
                 s = move_iovec_hdr(vq->iov, nvq->hdr, hdr_size, out);
-                msg.msg_iovlen = out;
                 len = iov_length(vq->iov, out);
+                iov_iter_init(&msg.msg_iter, WRITE, vq->iov, out, len);
                 /* Sanity check */
                 if (!len) {
                         vq_err(vq, "Unexpected header len for TX: "
@@ -562,7 +561,6 @@ static void handle_rx(struct vhost_net *net)
                 .msg_namelen = 0,
                 .msg_control = NULL, /* FIXME: get and handle RX aux data. */
                 .msg_controllen = 0,
-                .msg_iov = vq->iov,
                 .msg_flags = MSG_DONTWAIT,
         };
         struct virtio_net_hdr_mrg_rxbuf hdr = {
@@ -600,7 +598,7 @@ static void handle_rx(struct vhost_net *net)
                         break;
                 /* On overrun, truncate and discard */
                 if (unlikely(headcount > UIO_MAXIOV)) {
-                        msg.msg_iovlen = 1;
+                        iov_iter_init(&msg.msg_iter, READ, vq->iov, 1, 1);
                         err = sock->ops->recvmsg(NULL, sock, &msg,
                                                  1, MSG_DONTWAIT | MSG_TRUNC);
                         pr_debug("Discarded rx packet: len %zd\n", sock_len);
@@ -626,7 +624,7 @@ static void handle_rx(struct vhost_net *net)
                         /* Copy the header for use in VIRTIO_NET_F_MRG_RXBUF:
                          * needed because recvmsg can modify msg_iov. */
                         copy_iovec_hdr(vq->iov, nvq->hdr, sock_hlen, in);
-                msg.msg_iovlen = in;
+                iov_iter_init(&msg.msg_iter, READ, vq->iov, in, sock_len);
                 err = sock->ops->recvmsg(NULL, sock, &msg,
                                          sock_len, MSG_DONTWAIT | MSG_TRUNC);
                 /* Userspace might have consumed the packet meanwhile:
diff --git a/fs/afs/rxrpc.c b/fs/afs/rxrpc.c
index 03a3beb17004..06e14bfb3496 100644
--- a/fs/afs/rxrpc.c
+++ b/fs/afs/rxrpc.c
@@ -306,8 +306,8 @@ static int afs_send_pages(struct afs_call *call, struct msghdr *msg,
 
                         _debug("- range %u-%u%s",
                                offset, to, msg->msg_flags ? " [more]" : "");
-                        msg->msg_iov = (struct iovec *) iov;
-                        msg->msg_iovlen = 1;
+                        iov_iter_init(&msg->msg_iter, WRITE,
+                                      (struct iovec *) iov, 1, to - offset);
 
                         /* have to change the state *before* sending the last
                          * packet as RxRPC might give us the reply before it
@@ -384,8 +384,8 @@ int afs_make_call(struct in_addr *addr, struct afs_call *call, gfp_t gfp,
 
         msg.msg_name            = NULL;
         msg.msg_namelen         = 0;
-        msg.msg_iov             = (struct iovec *) iov;
-        msg.msg_iovlen          = 1;
+        iov_iter_init(&msg.msg_iter, WRITE, (struct iovec *)iov, 1,
+                      call->request_size);
         msg.msg_control         = NULL;
         msg.msg_controllen      = 0;
         msg.msg_flags           = (call->send_pages ? MSG_MORE : 0);
@@ -778,8 +778,7 @@ void afs_send_empty_reply(struct afs_call *call)
         iov[0].iov_len          = 0;
         msg.msg_name            = NULL;
         msg.msg_namelen         = 0;
-        msg.msg_iov             = iov;
-        msg.msg_iovlen          = 0;
+        iov_iter_init(&msg.msg_iter, WRITE, iov, 0, 0); /* WTF? */
         msg.msg_control         = NULL;
         msg.msg_controllen      = 0;
         msg.msg_flags           = 0;
@@ -815,8 +814,7 @@ void afs_send_simple_reply(struct afs_call *call, const void *buf, size_t len)
         iov[0].iov_len          = len;
         msg.msg_name            = NULL;
         msg.msg_namelen         = 0;
-        msg.msg_iov             = iov;
-        msg.msg_iovlen          = 1;
+        iov_iter_init(&msg.msg_iter, WRITE, iov, 1, len);
         msg.msg_control         = NULL;
         msg.msg_controllen      = 0;
         msg.msg_flags           = 0;
diff --git a/include/linux/skbuff.h b/include/linux/skbuff.h
index ef64cec42804..52cf1bdac0d8 100644
--- a/include/linux/skbuff.h
+++ b/include/linux/skbuff.h
@@ -2646,22 +2646,24 @@ unsigned int datagram_poll(struct file *file, struct socket *sock,
                            struct poll_table_struct *wait);
 int skb_copy_datagram_iovec(const struct sk_buff *from, int offset,
                             struct iovec *to, int size);
+int skb_copy_datagram_iter(const struct sk_buff *from, int offset,
+                           struct iov_iter *to, int size);
 static inline int skb_copy_datagram_msg(const struct sk_buff *from, int offset,
                                         struct msghdr *msg, int size)
 {
-        return skb_copy_datagram_iovec(from, offset, msg->msg_iov, size);
+        /* XXX: stripping const */
+        return skb_copy_datagram_iovec(from, offset, (struct iovec *)msg->msg_iter.iov, size);
 }
 int skb_copy_and_csum_datagram_iovec(struct sk_buff *skb, int hlen,
                                      struct iovec *iov);
 static inline int skb_copy_and_csum_datagram_msg(struct sk_buff *skb, int hlen,
                             struct msghdr *msg)
 {
-        return skb_copy_and_csum_datagram_iovec(skb, hlen, msg->msg_iov);
+        /* XXX: stripping const */
+        return skb_copy_and_csum_datagram_iovec(skb, hlen, (struct iovec *)msg->msg_iter.iov);
 }
 int skb_copy_datagram_from_iter(struct sk_buff *skb, int offset,
                                  struct iov_iter *from, int len);
-int skb_copy_datagram_iter(const struct sk_buff *from, int offset,
-                           struct iov_iter *to, int size);
 int zerocopy_sg_from_iter(struct sk_buff *skb, struct iov_iter *frm);
 void skb_free_datagram(struct sock *sk, struct sk_buff *skb);
 void skb_free_datagram_locked(struct sock *sk, struct sk_buff *skb);
@@ -2689,12 +2691,14 @@ int skb_vlan_push(struct sk_buff *skb, __be16 vlan_proto, u16 vlan_tci);
 
 static inline int memcpy_from_msg(void *data, struct msghdr *msg, int len)
 {
-        return memcpy_fromiovec(data, msg->msg_iov, len);
+        /* XXX: stripping const */
+        return memcpy_fromiovec(data, (struct iovec *)msg->msg_iter.iov, len);
 }
 
 static inline int memcpy_to_msg(struct msghdr *msg, void *data, int len)
 {
-        return memcpy_toiovec(msg->msg_iov, data, len);
+        /* XXX: stripping const */
+        return memcpy_toiovec((struct iovec *)msg->msg_iter.iov, data, len);
 }
 
 struct skb_checksum_ops {
diff --git a/include/linux/socket.h b/include/linux/socket.h
index de5222832be4..048d6d6eed6d 100644
--- a/include/linux/socket.h
+++ b/include/linux/socket.h
@@ -47,8 +47,7 @@ struct linger {
 struct msghdr {
         void            *msg_name;      /* ptr to socket address structure */
         int             msg_namelen;    /* size of socket address structure */
-        struct iovec    *msg_iov;       /* scatter/gather array */
-        __kernel_size_t msg_iovlen;     /* # elements in msg_iov */
+        struct iov_iter msg_iter;       /* data */
         void            *msg_control;   /* ancillary data */
         __kernel_size_t msg_controllen; /* ancillary data buffer length */
         unsigned int    msg_flags;      /* flags on received message */
diff --git a/include/net/bluetooth/l2cap.h b/include/net/bluetooth/l2cap.h
index 4e23674d3649..bca6fc0a3196 100644
--- a/include/net/bluetooth/l2cap.h
+++ b/include/net/bluetooth/l2cap.h
@@ -911,7 +911,7 @@ static inline int l2cap_chan_no_memcpy_fromiovec(struct l2cap_chan *chan,
         /* Following is safe since for compiler definitions of kvec and
          * iovec are identical, yielding the same in-core layout and alignment
          */
-        struct kvec *vec = (struct kvec *)msg->msg_iov;
+        struct kvec *vec = (struct kvec *)msg->msg_iter.iov;
 
         while (len > 0) {
                 if (vec->iov_len) {
diff --git a/include/net/udplite.h b/include/net/udplite.h
index d5baaba65b46..ae7c8d1fbcad 100644
--- a/include/net/udplite.h
+++ b/include/net/udplite.h
@@ -20,7 +20,8 @@ static __inline__ int udplite_getfrag(void *from, char *to, int  offset,
                                       int len, int odd, struct sk_buff *skb)
 {
         struct msghdr *msg = from;
-        return memcpy_fromiovecend(to, msg->msg_iov, offset, len);
+        /* XXX: stripping const */
+        return memcpy_fromiovecend(to, (struct iovec *)msg->msg_iter.iov, offset, len);
 }
 
 /* Designate sk as UDP-Lite socket */
diff --git a/net/atm/common.c b/net/atm/common.c
index f59112944c91..b84057e41bd6 100644
--- a/net/atm/common.c
+++ b/net/atm/common.c
@@ -577,9 +577,6 @@ int vcc_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *m,
         struct atm_vcc *vcc;
         struct sk_buff *skb;
         int eff, error;
-        struct iov_iter from;
-
-        iov_iter_init(&from, WRITE, m->msg_iov, m->msg_iovlen, size);
 
         lock_sock(sk);
         if (sock->state != SS_CONNECTED) {
@@ -634,7 +631,7 @@ int vcc_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *m,
                 goto out;
         skb->dev = NULL; /* for paths shared with net_device interfaces */
         ATM_SKB(skb)->atm_options = vcc->atm_options;
-        if (copy_from_iter(skb_put(skb, size), size, &from) != size) {
+        if (copy_from_iter(skb_put(skb, size), size, &m->msg_iter) != size) {
                 kfree_skb(skb);
                 error = -EFAULT;
                 goto out;
diff --git a/net/bluetooth/6lowpan.c b/net/bluetooth/6lowpan.c
index bdcaefd2db12..d8c67a5e7a02 100644
--- a/net/bluetooth/6lowpan.c
+++ b/net/bluetooth/6lowpan.c
@@ -537,12 +537,12 @@ static int send_pkt(struct l2cap_chan *chan, struct sk_buff *skb,
          */
         chan->data = skb;
 
-        memset(&msg, 0, sizeof(msg));
-        msg.msg_iov = (struct iovec *) &iv;
-        msg.msg_iovlen = 1;
         iv.iov_base = skb->data;
         iv.iov_len = skb->len;
 
+        memset(&msg, 0, sizeof(msg));
+        iov_iter_init(&msg.msg_iter, WRITE, (struct iovec *) &iv, 1, skb->len);
+
         err = l2cap_chan_send(chan, &msg, skb->len);
         if (err > 0) {
                 netdev->stats.tx_bytes += err;
diff --git a/net/bluetooth/a2mp.c b/net/bluetooth/a2mp.c
index 5dcade511fdb..716d2a388858 100644
--- a/net/bluetooth/a2mp.c
+++ b/net/bluetooth/a2mp.c
@@ -60,8 +60,7 @@ void a2mp_send(struct amp_mgr *mgr, u8 code, u8 ident, u16 len, void *data)
 
         memset(&msg, 0, sizeof(msg));
 
-        msg.msg_iov = (struct iovec *) &iv;
-        msg.msg_iovlen = 1;
+        iov_iter_init(&msg.msg_iter, WRITE, (struct iovec *)&iv, 1, total_len);
 
         l2cap_chan_send(chan, &msg, total_len);
 
diff --git a/net/bluetooth/smp.c b/net/bluetooth/smp.c
index 069b76e03b57..21f555b4df17 100644
--- a/net/bluetooth/smp.c
+++ b/net/bluetooth/smp.c
@@ -268,8 +268,7 @@ static void smp_send_cmd(struct l2cap_conn *conn, u8 code, u16 len, void *data)
 
         memset(&msg, 0, sizeof(msg));
 
-        msg.msg_iov = (struct iovec *) &iv;
-        msg.msg_iovlen = 2;
+        iov_iter_init(&msg.msg_iter, WRITE, (struct iovec *)iv, 2, 1 + len);
 
         l2cap_chan_send(chan, &msg, 1 + len);
 
diff --git a/net/caif/caif_socket.c b/net/caif/caif_socket.c
index ac618b0b8a4f..769b185fefbd 100644
--- a/net/caif/caif_socket.c
+++ b/net/caif/caif_socket.c
@@ -535,7 +535,7 @@ static int caif_seqpkt_sendmsg(struct kiocb *kiocb, struct socket *sock,
                 goto err;
 
         ret = -EINVAL;
-        if (unlikely(msg->msg_iov->iov_base == NULL))
+        if (unlikely(msg->msg_iter.iov->iov_base == NULL))
                 goto err;
         noblock = msg->msg_flags & MSG_DONTWAIT;
 
diff --git a/net/compat.c b/net/compat.c
index 062f157d2a6b..3236b4167a32 100644
--- a/net/compat.c
+++ b/net/compat.c
@@ -37,13 +37,14 @@ ssize_t get_compat_msghdr(struct msghdr *kmsg,
                           struct iovec **iov)
 {
         compat_uptr_t uaddr, uiov, tmp3;
+        compat_size_t nr_segs;
         ssize_t err;
 
         if (!access_ok(VERIFY_READ, umsg, sizeof(*umsg)) ||
             __get_user(uaddr, &umsg->msg_name) ||
             __get_user(kmsg->msg_namelen, &umsg->msg_namelen) ||
             __get_user(uiov, &umsg->msg_iov) ||
-            __get_user(kmsg->msg_iovlen, &umsg->msg_iovlen) ||
+            __get_user(nr_segs, &umsg->msg_iovlen) ||
             __get_user(tmp3, &umsg->msg_control) ||
             __get_user(kmsg->msg_controllen, &umsg->msg_controllen) ||
             __get_user(kmsg->msg_flags, &umsg->msg_flags))
@@ -68,14 +69,15 @@ ssize_t get_compat_msghdr(struct msghdr *kmsg,
                 kmsg->msg_namelen = 0;
         }
 
-        if (kmsg->msg_iovlen > UIO_MAXIOV)
+        if (nr_segs > UIO_MAXIOV)
                 return -EMSGSIZE;
 
         err = compat_rw_copy_check_uvector(save_addr ? READ : WRITE,
-                                           compat_ptr(uiov), kmsg->msg_iovlen,
+                                           compat_ptr(uiov), nr_segs,
                                            UIO_FASTIOV, *iov, iov);
         if (err >= 0)
-                kmsg->msg_iov = *iov;
+                iov_iter_init(&kmsg->msg_iter, save_addr ? READ : WRITE,
+                              *iov, nr_segs, err);
         return err;
 }
 
diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c
index cdedcf144463..b50861b22b6b 100644
--- a/net/ipv4/ip_output.c
+++ b/net/ipv4/ip_output.c
@@ -755,11 +755,13 @@ ip_generic_getfrag(void *from, char *to, int offset, int len, int odd, struct sk
         struct msghdr *msg = from;
 
         if (skb->ip_summed == CHECKSUM_PARTIAL) {
-                if (memcpy_fromiovecend(to, msg->msg_iov, offset, len) < 0)
+                /* XXX: stripping const */
+                if (memcpy_fromiovecend(to, (struct iovec *)msg->msg_iter.iov, offset, len) < 0)
                         return -EFAULT;
         } else {
                 __wsum csum = 0;
-                if (csum_partial_copy_fromiovecend(to, msg->msg_iov, offset, len, &csum) < 0)
+                /* XXX: stripping const */
+                if (csum_partial_copy_fromiovecend(to, (struct iovec *)msg->msg_iter.iov, offset, len, &csum) < 0)
                         return -EFAULT;
                 skb->csum = csum_block_add(skb->csum, csum, odd);
         }
diff --git a/net/ipv4/ping.c b/net/ipv4/ping.c
index 8dd4ae0424fc..c0d82f78d364 100644
--- a/net/ipv4/ping.c
+++ b/net/ipv4/ping.c
@@ -811,7 +811,8 @@ back_from_confirm:
         pfh.icmph.checksum = 0;
         pfh.icmph.un.echo.id = inet->inet_sport;
         pfh.icmph.un.echo.sequence = user_icmph.un.echo.sequence;
-        pfh.iov = msg->msg_iov;
+        /* XXX: stripping const */
+        pfh.iov = (struct iovec *)msg->msg_iter.iov;
         pfh.wcheck = 0;
         pfh.family = AF_INET;
 
diff --git a/net/ipv4/raw.c b/net/ipv4/raw.c
index 5d83bd2fcedb..0bb68df5055d 100644
--- a/net/ipv4/raw.c
+++ b/net/ipv4/raw.c
@@ -625,7 +625,8 @@ static int raw_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
 back_from_confirm:
 
         if (inet->hdrincl)
-                err = raw_send_hdrinc(sk, &fl4, msg->msg_iov, len,
+                /* XXX: stripping const */
+                err = raw_send_hdrinc(sk, &fl4, (struct iovec *)msg->msg_iter.iov, len,
                                       &rt, msg->msg_flags);
 
          else {
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 4a96f3730170..54ba6209eea9 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1085,7 +1085,7 @@ static int tcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg,
 int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
                 size_t size)
 {
-        struct iovec *iov;
+        const struct iovec *iov;
         struct tcp_sock *tp = tcp_sk(sk);
         struct sk_buff *skb;
         int iovlen, flags, err, copied = 0;
@@ -1136,8 +1136,8 @@ int tcp_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
         mss_now = tcp_send_mss(sk, &size_goal, flags);
 
         /* Ok commence sending. */
-        iovlen = msg->msg_iovlen;
-        iov = msg->msg_iov;
+        iovlen = msg->msg_iter.nr_segs;
+        iov = msg->msg_iter.iov;
         copied = 0;
 
         err = -EPIPE;
diff --git a/net/ipv4/tcp_output.c b/net/ipv4/tcp_output.c
index f5bd4bd3f7e6..3e225b03eb95 100644
--- a/net/ipv4/tcp_output.c
+++ b/net/ipv4/tcp_output.c
@@ -3050,7 +3050,7 @@ static int tcp_send_syn_data(struct sock *sk, struct sk_buff *syn)
         syn_data->ip_summed = CHECKSUM_PARTIAL;
         memcpy(syn_data->cb, syn->cb, sizeof(syn->cb));
         if (unlikely(memcpy_fromiovecend(skb_put(syn_data, space),
-                                         fo->data->msg_iov, 0, space))) {
+                                         fo->data->msg_iter.iov, 0, space))) {
                 kfree_skb(syn_data);
                 goto fallback;
         }
diff --git a/net/ipv6/ping.c b/net/ipv6/ping.c
index 5b7a1ed2aba9..2d3148378a1f 100644
--- a/net/ipv6/ping.c
+++ b/net/ipv6/ping.c
@@ -163,7 +163,8 @@ int ping_v6_sendmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
         pfh.icmph.checksum = 0;
         pfh.icmph.un.echo.id = inet->inet_sport;
         pfh.icmph.un.echo.sequence = user_icmph.icmp6_sequence;
-        pfh.iov = msg->msg_iov;
+        /* XXX: stripping const */
+        pfh.iov = (struct iovec *)msg->msg_iter.iov;
         pfh.wcheck = 0;
         pfh.family = AF_INET6;
 
diff --git a/net/ipv6/raw.c b/net/ipv6/raw.c
index 11a9283fda51..ee25631f8c29 100644
--- a/net/ipv6/raw.c
+++ b/net/ipv6/raw.c
@@ -886,7 +886,8 @@ static int rawv6_sendmsg(struct kiocb *iocb, struct sock *sk,
 
 back_from_confirm:
         if (inet->hdrincl)
-                err = rawv6_send_hdrinc(sk, msg->msg_iov, len, &fl6, &dst, msg->msg_flags);
+                /* XXX: stripping const */
+                err = rawv6_send_hdrinc(sk, (struct iovec *)msg->msg_iter.iov, len, &fl6, &dst, msg->msg_flags);
         else {
                 lock_sock(sk);
                 err = ip6_append_data(sk, raw6_getfrag, &rfv,
diff --git a/net/netlink/af_netlink.c b/net/netlink/af_netlink.c
index 63aa5c8acf12..cc9bcf008b03 100644
--- a/net/netlink/af_netlink.c
+++ b/net/netlink/af_netlink.c
@@ -2305,7 +2305,7 @@ static int netlink_sendmsg(struct kiocb *kiocb, struct socket *sock,
         }
 
         if (netlink_tx_is_mmaped(sk) &&
-            msg->msg_iov->iov_base == NULL) {
+            msg->msg_iter.iov->iov_base == NULL) {
                 err = netlink_mmap_sendmsg(sk, msg, dst_portid, dst_group,
                                            siocb);
                 goto out;
diff --git a/net/packet/af_packet.c b/net/packet/af_packet.c
index efa844501136..ed2e620b61df 100644
--- a/net/packet/af_packet.c
+++ b/net/packet/af_packet.c
@@ -2408,11 +2408,8 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len)
         unsigned short gso_type = 0;
         int hlen, tlen;
         int extra_len = 0;
-        struct iov_iter from;
         ssize_t n;
 
-        iov_iter_init(&from, WRITE, msg->msg_iov, msg->msg_iovlen, len);
-
         /*
          *      Get and verify the address.
          */
@@ -2451,7 +2448,7 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len)
                 len -= vnet_hdr_len;
 
                 err = -EFAULT;
-                n = copy_from_iter(&vnet_hdr, vnet_hdr_len, &from);
+                n = copy_from_iter(&vnet_hdr, vnet_hdr_len, &msg->msg_iter);
                 if (n != vnet_hdr_len)
                         goto out_unlock;
 
@@ -2522,7 +2519,7 @@ static int packet_snd(struct socket *sock, struct msghdr *msg, size_t len)
         }
 
         /* Returns -EFAULT on error */
-        err = skb_copy_datagram_from_iter(skb, offset, &from, len);
+        err = skb_copy_datagram_from_iter(skb, offset, &msg->msg_iter, len);
         if (err)
                 goto out_free;
 
diff --git a/net/rds/recv.c b/net/rds/recv.c
index 47d7b1029b33..f9ec1acd801c 100644
--- a/net/rds/recv.c
+++ b/net/rds/recv.c
@@ -404,7 +404,6 @@ int rds_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
         int ret = 0, nonblock = msg_flags & MSG_DONTWAIT;
         DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
         struct rds_incoming *inc = NULL;
-        struct iov_iter to;
 
         /* udp_recvmsg()->sock_recvtimeo() gets away without locking too.. */
         timeo = sock_rcvtimeo(sk, nonblock);
@@ -415,6 +414,7 @@ int rds_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
                 goto out;
 
         while (1) {
+                struct iov_iter save;
                 /* If there are pending notifications, do those - and nothing else */
                 if (!list_empty(&rs->rs_notify_queue)) {
                         ret = rds_notify_queue_get(rs, msg);
@@ -450,8 +450,8 @@ int rds_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
                 rdsdebug("copying inc %p from %pI4:%u to user\n", inc,
                          &inc->i_conn->c_faddr,
                          ntohs(inc->i_hdr.h_sport));
-                iov_iter_init(&to, READ, msg->msg_iov, msg->msg_iovlen, size);
-                ret = inc->i_conn->c_trans->inc_copy_to_user(inc, &to);
+                save = msg->msg_iter;
+                ret = inc->i_conn->c_trans->inc_copy_to_user(inc, &msg->msg_iter);
                 if (ret < 0)
                         break;
 
@@ -464,6 +464,7 @@ int rds_recvmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
                         rds_inc_put(inc);
                         inc = NULL;
                         rds_stats_inc(s_recv_deliver_raced);
+                        msg->msg_iter = save;
                         continue;
                 }
 
diff --git a/net/rds/send.c b/net/rds/send.c
index 4de62ead1c71..40a5629a0a13 100644
--- a/net/rds/send.c
+++ b/net/rds/send.c
@@ -934,9 +934,7 @@ int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
         int queued = 0, allocated_mr = 0;
         int nonblock = msg->msg_flags & MSG_DONTWAIT;
         long timeo = sock_sndtimeo(sk, nonblock);
-        struct iov_iter from;
 
-        iov_iter_init(&from, WRITE, msg->msg_iov, msg->msg_iovlen, payload_len);
         /* Mirror Linux UDP mirror of BSD error message compatibility */
         /* XXX: Perhaps MSG_MORE someday */
         if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_CMSG_COMPAT)) {
@@ -984,7 +982,7 @@ int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
                         ret = -ENOMEM;
                         goto out;
                 }
-                ret = rds_message_copy_from_user(rm, &from);
+                ret = rds_message_copy_from_user(rm, &msg->msg_iter);
                 if (ret)
                         goto out;
         }
diff --git a/net/rxrpc/ar-output.c b/net/rxrpc/ar-output.c
index 0b4b9a79f5ab..86e0f10aa2c0 100644
--- a/net/rxrpc/ar-output.c
+++ b/net/rxrpc/ar-output.c
@@ -531,14 +531,12 @@ static int rxrpc_send_data(struct kiocb *iocb,
         struct rxrpc_skb_priv *sp;
         unsigned char __user *from;
         struct sk_buff *skb;
-        struct iovec *iov;
+        const struct iovec *iov;
         struct sock *sk = &rx->sk;
         long timeo;
         bool more;
         int ret, ioc, segment, copied;
 
-        _enter(",,,{%zu},%zu", msg->msg_iovlen, len);
-
         timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
 
         /* this should be in poll */
@@ -547,8 +545,8 @@ static int rxrpc_send_data(struct kiocb *iocb,
         if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
                 return -EPIPE;
 
-        iov = msg->msg_iov;
-        ioc = msg->msg_iovlen - 1;
+        iov = msg->msg_iter.iov;
+        ioc = msg->msg_iter.nr_segs - 1;
         from = iov->iov_base;
         segment = iov->iov_len;
         iov++;
diff --git a/net/sctp/socket.c b/net/sctp/socket.c
index 0397ac9fd98c..c92f96cda699 100644
--- a/net/sctp/socket.c
+++ b/net/sctp/socket.c
@@ -1609,9 +1609,6 @@ static int sctp_sendmsg(struct kiocb *iocb, struct sock *sk,
         __u16 sinfo_flags = 0;
         long timeo;
         int err;
-        struct iov_iter from;
-
-        iov_iter_init(&from, WRITE, msg->msg_iov, msg->msg_iovlen, msg_len);
 
         err = 0;
         sp = sctp_sk(sk);
@@ -1950,7 +1947,7 @@ static int sctp_sendmsg(struct kiocb *iocb, struct sock *sk,
         }
 
         /* Break the message into multiple chunks of maximum size. */
-        datamsg = sctp_datamsg_from_user(asoc, sinfo, &from);
+        datamsg = sctp_datamsg_from_user(asoc, sinfo, &msg->msg_iter);
         if (IS_ERR(datamsg)) {
                 err = PTR_ERR(datamsg);
                 goto out_free;
diff --git a/net/socket.c b/net/socket.c
index f676ac4a3701..8809afccf7fa 100644
--- a/net/socket.c
+++ b/net/socket.c
@@ -689,8 +689,7 @@ int kernel_sendmsg(struct socket *sock, struct msghdr *msg,
          * the following is safe, since for compiler definitions of kvec and
          * iovec are identical, yielding the same in-core layout and alignment
          */
-        msg->msg_iov = (struct iovec *)vec;
-        msg->msg_iovlen = num;
+        iov_iter_init(&msg->msg_iter, WRITE, (struct iovec *)vec, num, size);
         result = sock_sendmsg(sock, msg, size);
         set_fs(oldfs);
         return result;
@@ -853,7 +852,7 @@ int kernel_recvmsg(struct socket *sock, struct msghdr *msg,
          * the following is safe, since for compiler definitions of kvec and
          * iovec are identical, yielding the same in-core layout and alignment
          */
-        msg->msg_iov = (struct iovec *)vec, msg->msg_iovlen = num;
+        iov_iter_init(&msg->msg_iter, READ, (struct iovec *)vec, num, size);
         result = sock_recvmsg(sock, msg, size, flags);
         set_fs(oldfs);
         return result;
@@ -913,8 +912,7 @@ static ssize_t do_sock_read(struct msghdr *msg, struct kiocb *iocb,
         msg->msg_namelen = 0;
         msg->msg_control = NULL;
         msg->msg_controllen = 0;
-        msg->msg_iov = (struct iovec *)iov;
-        msg->msg_iovlen = nr_segs;
+        iov_iter_init(&msg->msg_iter, READ, iov, nr_segs, size);
         msg->msg_flags = (file->f_flags & O_NONBLOCK) ? MSG_DONTWAIT : 0;
 
         return __sock_recvmsg(iocb, sock, msg, size, msg->msg_flags);
@@ -953,8 +951,7 @@ static ssize_t do_sock_write(struct msghdr *msg, struct kiocb *iocb,
         msg->msg_namelen = 0;
         msg->msg_control = NULL;
         msg->msg_controllen = 0;
-        msg->msg_iov = (struct iovec *)iov;
-        msg->msg_iovlen = nr_segs;
+        iov_iter_init(&msg->msg_iter, WRITE, iov, nr_segs, size);
         msg->msg_flags = (file->f_flags & O_NONBLOCK) ? MSG_DONTWAIT : 0;
         if (sock->type == SOCK_SEQPACKET)
                 msg->msg_flags |= MSG_EOR;
@@ -1798,8 +1795,7 @@ SYSCALL_DEFINE6(sendto, int, fd, void __user *, buff, size_t, len,
         iov.iov_base = buff;
         iov.iov_len = len;
         msg.msg_name = NULL;
-        msg.msg_iov = &iov;
-        msg.msg_iovlen = 1;
+        iov_iter_init(&msg.msg_iter, WRITE, &iov, 1, len);
         msg.msg_control = NULL;
         msg.msg_controllen = 0;
         msg.msg_namelen = 0;
@@ -1856,10 +1852,9 @@ SYSCALL_DEFINE6(recvfrom, int, fd, void __user *, ubuf, size_t, size,
 
         msg.msg_control = NULL;
         msg.msg_controllen = 0;
-        msg.msg_iovlen = 1;
-        msg.msg_iov = &iov;
         iov.iov_len = size;
         iov.iov_base = ubuf;
+        iov_iter_init(&msg.msg_iter, READ, &iov, 1, size);
         /* Save some cycles and don't copy the address if not needed */
         msg.msg_name = addr ? (struct sockaddr *)&address : NULL;
         /* We assume all kernel code knows the size of sockaddr_storage */
@@ -1993,13 +1988,14 @@ static ssize_t copy_msghdr_from_user(struct msghdr *kmsg,
 {
         struct sockaddr __user *uaddr;
         struct iovec __user *uiov;
+        size_t nr_segs;
         ssize_t err;
 
         if (!access_ok(VERIFY_READ, umsg, sizeof(*umsg)) ||
             __get_user(uaddr, &umsg->msg_name) ||
             __get_user(kmsg->msg_namelen, &umsg->msg_namelen) ||
             __get_user(uiov, &umsg->msg_iov) ||
-            __get_user(kmsg->msg_iovlen, &umsg->msg_iovlen) ||
+            __get_user(nr_segs, &umsg->msg_iovlen) ||
             __get_user(kmsg->msg_control, &umsg->msg_control) ||
             __get_user(kmsg->msg_controllen, &umsg->msg_controllen) ||
             __get_user(kmsg->msg_flags, &umsg->msg_flags))
@@ -2029,14 +2025,15 @@ static ssize_t copy_msghdr_from_user(struct msghdr *kmsg,
                 kmsg->msg_namelen = 0;
         }
 
-        if (kmsg->msg_iovlen > UIO_MAXIOV)
+        if (nr_segs > UIO_MAXIOV)
                 return -EMSGSIZE;
 
         err = rw_copy_check_uvector(save_addr ? READ : WRITE,
-                                    uiov, kmsg->msg_iovlen,
+                                    uiov, nr_segs,
                                     UIO_FASTIOV, *iov, iov);
         if (err >= 0)
-                kmsg->msg_iov = *iov;
+                iov_iter_init(&kmsg->msg_iter, save_addr ? READ : WRITE,
+                              *iov, nr_segs, err);
         return err;
 }
 
diff --git a/net/tipc/msg.c b/net/tipc/msg.c
index 5b0659791c07..a687b30a699c 100644
--- a/net/tipc/msg.c
+++ b/net/tipc/msg.c
@@ -194,7 +194,7 @@ int tipc_msg_build(struct tipc_msg *mhdr, struct msghdr *m, int offset,
                 __skb_queue_tail(list, skb);
                 skb_copy_to_linear_data(skb, mhdr, mhsz);
                 pktpos = skb->data + mhsz;
-                if (!dsz || !memcpy_fromiovecend(pktpos, m->msg_iov, offset,
+                if (!dsz || !memcpy_fromiovecend(pktpos, m->msg_iter.iov, offset,
                                                  dsz))
                         return dsz;
                 rc = -EFAULT;
@@ -224,7 +224,7 @@ int tipc_msg_build(struct tipc_msg *mhdr, struct msghdr *m, int offset,
                 if (drem < pktrem)
                         pktrem = drem;
 
-                if (memcpy_fromiovecend(pktpos, m->msg_iov, offset, pktrem)) {
+                if (memcpy_fromiovecend(pktpos, m->msg_iter.iov, offset, pktrem)) {
                         rc = -EFAULT;
                         goto error;
                 }
diff --git a/net/unix/af_unix.c b/net/unix/af_unix.c
index 4450d6226602..8e1b10274b02 100644
--- a/net/unix/af_unix.c
+++ b/net/unix/af_unix.c
@@ -1459,9 +1459,6 @@ static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
         struct scm_cookie tmp_scm;
         int max_level;
         int data_len = 0;
-        struct iov_iter from;
-
-        iov_iter_init(&from, WRITE, msg->msg_iov, msg->msg_iovlen, len);
 
         if (NULL == siocb->scm)
                 siocb->scm = &tmp_scm;
@@ -1519,7 +1516,7 @@ static int unix_dgram_sendmsg(struct kiocb *kiocb, struct socket *sock,
         skb_put(skb, len - data_len);
         skb->data_len = data_len;
         skb->len = len;
-        err = skb_copy_datagram_from_iter(skb, 0, &from, len);
+        err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, len);
         if (err)
                 goto out_free;
 
@@ -1641,9 +1638,6 @@ static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
         bool fds_sent = false;
         int max_level;
         int data_len;
-        struct iov_iter from;
-
-        iov_iter_init(&from, WRITE, msg->msg_iov, msg->msg_iovlen, len);
 
         if (NULL == siocb->scm)
                 siocb->scm = &tmp_scm;
@@ -1700,7 +1694,7 @@ static int unix_stream_sendmsg(struct kiocb *kiocb, struct socket *sock,
                 skb_put(skb, size - data_len);
                 skb->data_len = data_len;
                 skb->len = size;
-                err = skb_copy_datagram_from_iter(skb, 0, &from, size);
+                err = skb_copy_datagram_from_iter(skb, 0, &msg->msg_iter, size);
                 if (err) {
                         kfree_skb(skb);
                         goto out_err;
diff --git a/net/vmw_vsock/vmci_transport.c b/net/vmw_vsock/vmci_transport.c
index 20a0ba3bfff6..02d2e5229240 100644
--- a/net/vmw_vsock/vmci_transport.c
+++ b/net/vmw_vsock/vmci_transport.c
@@ -1850,7 +1850,8 @@ static ssize_t vmci_transport_stream_enqueue(
         struct msghdr *msg,
         size_t len)
 {
-        return vmci_qpair_enquev(vmci_trans(vsk)->qpair, msg->msg_iov, len, 0);
+        /* XXX: stripping const */
+        return vmci_qpair_enquev(vmci_trans(vsk)->qpair, (struct iovec *)msg->msg_iter.iov, len, 0);
 }
 
 static s64 vmci_transport_stream_has_data(struct vsock_sock *vsk)