Revert "udp: remove redundant variable"

This reverts commit 81d54ec8479a2c695760da81f05b5a9fb2dbe40a.

If we take the "try_again" goto, due to a checksum error,
the 'len' has already been truncated.  So we won't compute
the same values as the original code did.

Reported-by: paul bilke <fsmail@conspiracy.net>
Signed-off-by: David S. Miller <davem@davemloft.net>

2 files changed, 16 insertions, 14 deletions

diff --git a/net/ipv4/udp.c b/net/ipv4/udp.c
index ab0966df1e2..5a65eeac1d2 100644
--- a/net/ipv4/udp.c
+++ b/net/ipv4/udp.c
@@ -1164,7 +1164,7 @@ int udp_recvmsg(struct kiocb *iocb, struct sock *sk, struct msghdr *msg,
         struct inet_sock *inet = inet_sk(sk);
         struct sockaddr_in *sin = (struct sockaddr_in *)msg->msg_name;
         struct sk_buff *skb;
-        unsigned int ulen;
+        unsigned int ulen, copied;
         int peeked;
         int err;
         int is_udplite = IS_UDPLITE(sk);
@@ -1186,9 +1186,10 @@ try_again:
                 goto out;
 
         ulen = skb->len - sizeof(struct udphdr);
-        if (len > ulen)
-                len = ulen;
-        else if (len < ulen)
+        copied = len;
+        if (copied > ulen)
+                copied = ulen;
+        else if (copied < ulen)
                 msg->msg_flags |= MSG_TRUNC;
 
         /*
@@ -1197,14 +1198,14 @@ try_again:
          * coverage checksum (UDP-Lite), do it before the copy.
          */
 
-        if (len < ulen || UDP_SKB_CB(skb)->partial_cov) {
+        if (copied < ulen || UDP_SKB_CB(skb)->partial_cov) {
                 if (udp_lib_checksum_complete(skb))
                         goto csum_copy_err;
         }
 
         if (skb_csum_unnecessary(skb))
                 err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr),
-                                              msg->msg_iov, len);
+                                              msg->msg_iov, copied);
         else {
                 err = skb_copy_and_csum_datagram_iovec(skb,
                                                        sizeof(struct udphdr),
@@ -1233,7 +1234,7 @@ try_again:
         if (inet->cmsg_flags)
                 ip_cmsg_recv(msg, skb);
 
-        err = len;
+        err = copied;
         if (flags & MSG_TRUNC)
                 err = ulen;
 
diff --git a/net/ipv6/udp.c b/net/ipv6/udp.c
index 846f4757eb8..8c254191518 100644
--- a/net/ipv6/udp.c
+++ b/net/ipv6/udp.c
@@ -340,7 +340,7 @@ int udpv6_recvmsg(struct kiocb *iocb, struct sock *sk,
         struct ipv6_pinfo *np = inet6_sk(sk);
         struct inet_sock *inet = inet_sk(sk);
         struct sk_buff *skb;
-        unsigned int ulen;
+        unsigned int ulen, copied;
         int peeked;
         int err;
         int is_udplite = IS_UDPLITE(sk);
@@ -363,9 +363,10 @@ try_again:
                 goto out;
 
         ulen = skb->len - sizeof(struct udphdr);
-        if (len > ulen)
-                len = ulen;
-        else if (len < ulen)
+        copied = len;
+        if (copied > ulen)
+                copied = ulen;
+        else if (copied < ulen)
                 msg->msg_flags |= MSG_TRUNC;
 
         is_udp4 = (skb->protocol == htons(ETH_P_IP));
@@ -376,14 +377,14 @@ try_again:
          * coverage checksum (UDP-Lite), do it before the copy.
          */
 
-        if (len < ulen || UDP_SKB_CB(skb)->partial_cov) {
+        if (copied < ulen || UDP_SKB_CB(skb)->partial_cov) {
                 if (udp_lib_checksum_complete(skb))
                         goto csum_copy_err;
         }
 
         if (skb_csum_unnecessary(skb))
                 err = skb_copy_datagram_iovec(skb, sizeof(struct udphdr),
-                                              msg->msg_iov,len);
+                                              msg->msg_iov, copied       );
         else {
                 err = skb_copy_and_csum_datagram_iovec(skb, sizeof(struct udphdr), msg->msg_iov);
                 if (err == -EINVAL)
@@ -432,7 +433,7 @@ try_again:
                         datagram_recv_ctl(sk, msg, skb);
         }
 
-        err = len;
+        err = copied;
         if (flags & MSG_TRUNC)
                 err = ulen;