tipc: Allow receiving into iovec containing multiple entries

Enhances TIPC's socket receive routines to support iovec structures
containing more than a single entry. This change leverages existing
sk_buff routines to do most of the work; the only significant change
to TIPC itself is that an sk_buff now records how much data has been
already consumed as an numeric offset, rather than as a pointer to
the first unread data byte.

Signed-off-by: Allan Stephens <Allan.Stephens@windriver.com>
Signed-off-by: Paul Gortmaker <paul.gortmaker@windriver.com>

1 files changed, 15 insertions, 23 deletions

diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index 125dcb0737b2..d45a294f47e9 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -289,7 +289,7 @@ static int release(struct socket *sock)
                 if (buf == NULL)
                         break;
                 atomic_dec(&tipc_queue_size);
-                if (TIPC_SKB_CB(buf)->handle != msg_data(buf_msg(buf)))
+                if (TIPC_SKB_CB(buf)->handle != 0)
                         buf_discard(buf);
                 else {
                         if ((sock->state == SS_CONNECTING) ||
@@ -917,9 +917,6 @@ static int recv_msg(struct kiocb *iocb, struct socket *sock,
 
         /* Catch invalid receive requests */
 
-        if (m->msg_iovlen != 1)
-                return -EOPNOTSUPP;   /* Don't do multiple iovec entries yet */
-
         if (unlikely(!buf_len))
                 return -EINVAL;
 
@@ -991,11 +988,10 @@ restart:
                         sz = buf_len;
                         m->msg_flags |= MSG_TRUNC;
                 }
-                if (unlikely(copy_to_user(m->msg_iov->iov_base, msg_data(msg),
-                                          sz))) {
-                        res = -EFAULT;
+                res = skb_copy_datagram_iovec(buf, msg_hdr_sz(msg),
+                                              m->msg_iov, sz);
+                if (res)
                         goto exit;
-                }
                 res = sz;
         } else {
                 if ((sock->state == SS_READY) ||
@@ -1041,16 +1037,11 @@ static int recv_stream(struct kiocb *iocb, struct socket *sock,
         unsigned int sz;
         int sz_to_copy, target, needed;
         int sz_copied = 0;
-        char __user *crs = m->msg_iov->iov_base;
-        unsigned char *buf_crs;
         u32 err;
         int res = 0;
 
         /* Catch invalid receive attempts */
 
-        if (m->msg_iovlen != 1)
-                return -EOPNOTSUPP;   /* Don't do multiple iovec entries yet */
-
         if (unlikely(!buf_len))
                 return -EINVAL;
 
@@ -1112,24 +1103,25 @@ restart:
         /* Capture message data (if valid) & compute return value (always) */
 
         if (!err) {
-                buf_crs = (unsigned char *)(TIPC_SKB_CB(buf)->handle);
-                sz = (unsigned char *)msg + msg_size(msg) - buf_crs;
+                u32 offset = (u32)(unsigned long)(TIPC_SKB_CB(buf)->handle);
 
+                sz -= offset;
                 needed = (buf_len - sz_copied);
                 sz_to_copy = (sz <= needed) ? sz : needed;
-                if (unlikely(copy_to_user(crs, buf_crs, sz_to_copy))) {
-                        res = -EFAULT;
+
+                res = skb_copy_datagram_iovec(buf, msg_hdr_sz(msg) + offset,
+                                              m->msg_iov, sz_to_copy);
+                if (res)
                         goto exit;
-                }
+
                 sz_copied += sz_to_copy;
 
                 if (sz_to_copy < sz) {
                         if (!(flags & MSG_PEEK))
-                                TIPC_SKB_CB(buf)->handle = buf_crs + sz_to_copy;
+                                TIPC_SKB_CB(buf)->handle =
+                                (void *)(unsigned long)(offset + sz_to_copy);
                         goto exit;
                 }
-
-                crs += sz_to_copy;
         } else {
                 if (sz_copied != 0)
                         goto exit; /* can't add error msg to valid data */
@@ -1256,7 +1248,7 @@ static u32 filter_rcv(struct sock *sk, struct sk_buff *buf)
 
         /* Enqueue message (finally!) */
 
-        TIPC_SKB_CB(buf)->handle = msg_data(msg);
+        TIPC_SKB_CB(buf)->handle = 0;
         atomic_inc(&tipc_queue_size);
         __skb_queue_tail(&sk->sk_receive_queue, buf);
 
@@ -1608,7 +1600,7 @@ restart:
                 buf = __skb_dequeue(&sk->sk_receive_queue);
                 if (buf) {
                         atomic_dec(&tipc_queue_size);
-                        if (TIPC_SKB_CB(buf)->handle != msg_data(buf_msg(buf))) {
+                        if (TIPC_SKB_CB(buf)->handle != 0) {
                                 buf_discard(buf);
                                 goto restart;
                         }