tipc: tipc ->sendmsg() conversion

This one needs to copy the same data from user potentially more than
once.  Sadly, MTU changes can trigger that ;-/

Cc: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>

2 files changed, 14 insertions, 7 deletions

diff --git a/net/tipc/msg.c b/net/tipc/msg.c
index 18aba9e99345..da67c8d3edc6 100644
--- a/net/tipc/msg.c
+++ b/net/tipc/msg.c
@@ -189,7 +189,6 @@ err:
  * tipc_msg_build - create buffer chain containing specified header and data
  * @mhdr: Message header, to be prepended to data
  * @m: User message
- * @offset: Posision in iov to start copying from
  * @dsz: Total length of user data
  * @pktmax: Max packet size that can be used
  * @list: Buffer or chain of buffers to be returned to caller
@@ -221,8 +220,7 @@ int tipc_msg_build(struct net *net, struct tipc_msg *mhdr, struct msghdr *m,
                 __skb_queue_tail(list, skb);
                 skb_copy_to_linear_data(skb, mhdr, mhsz);
                 pktpos = skb->data + mhsz;
-                if (!dsz || !memcpy_fromiovecend(pktpos, m->msg_iter.iov, offset,
-                                                 dsz))
+                if (copy_from_iter(pktpos, dsz, &m->msg_iter) == dsz)
                         return dsz;
                 rc = -EFAULT;
                 goto error;
@@ -252,12 +250,11 @@ int tipc_msg_build(struct net *net, struct tipc_msg *mhdr, struct msghdr *m,
                 if (drem < pktrem)
                         pktrem = drem;
 
-                if (memcpy_fromiovecend(pktpos, m->msg_iter.iov, offset, pktrem)) {
+                if (copy_from_iter(pktpos, pktrem, &m->msg_iter) != pktrem) {
                         rc = -EFAULT;
                         goto error;
                 }
                 drem -= pktrem;
-                offset += pktrem;
 
                 if (!drem)
                         break;
diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 679a22082fcb..caa4d663fd90 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -733,6 +733,7 @@ static int tipc_sendmcast(struct  socket *sock, struct tipc_name_seq *seq,
         struct net *net = sock_net(sk);
         struct tipc_msg *mhdr = &tipc_sk(sk)->phdr;
         struct sk_buff_head head;
+        struct iov_iter save = msg->msg_iter;
         uint mtu;
         int rc;
 
@@ -758,8 +759,10 @@ new_mtu:
                         rc = dsz;
                         break;
                 }
-                if (rc == -EMSGSIZE)
+                if (rc == -EMSGSIZE) {
+                        msg->msg_iter = save;
                         goto new_mtu;
+                }
                 if (rc != -ELINKCONG)
                         break;
                 tipc_sk(sk)->link_cong = 1;
@@ -895,6 +898,7 @@ static int tipc_sendmsg(struct kiocb *iocb, struct socket *sock,
         struct sk_buff_head head;
         struct sk_buff *skb;
         struct tipc_name_seq *seq = &dest->addr.nameseq;
+        struct iov_iter save;
         u32 mtu;
         long timeo;
         int rc;
@@ -963,6 +967,7 @@ static int tipc_sendmsg(struct kiocb *iocb, struct socket *sock,
                 msg_set_hdr_sz(mhdr, BASIC_H_SIZE);
         }
 
+        save = m->msg_iter;
 new_mtu:
         mtu = tipc_node_get_mtu(net, dnode, tsk->portid);
         __skb_queue_head_init(&head);
@@ -980,8 +985,10 @@ new_mtu:
                         rc = dsz;
                         break;
                 }
-                if (rc == -EMSGSIZE)
+                if (rc == -EMSGSIZE) {
+                        m->msg_iter = save;
                         goto new_mtu;
+                }
                 if (rc != -ELINKCONG)
                         break;
                 tsk->link_cong = 1;
@@ -1052,6 +1059,7 @@ static int tipc_send_stream(struct kiocb *iocb, struct socket *sock,
         long timeo;
         u32 dnode;
         uint mtu, send, sent = 0;
+        struct iov_iter save;
 
         /* Handle implied connection establishment */
         if (unlikely(dest)) {
@@ -1078,6 +1086,7 @@ static int tipc_send_stream(struct kiocb *iocb, struct socket *sock,
         dnode = tsk_peer_node(tsk);
 
 next:
+        save = m->msg_iter;
         mtu = tsk->max_pkt;
         send = min_t(uint, dsz - sent, TIPC_MAX_USER_MSG_SIZE);
         __skb_queue_head_init(&head);
@@ -1097,6 +1106,7 @@ next:
                         if (rc == -EMSGSIZE) {
                                 tsk->max_pkt = tipc_node_get_mtu(net, dnode,
                                                                  portid);
+                                m->msg_iter = save;
                                 goto next;
                         }
                         if (rc != -ELINKCONG)