caif: Bugfix - use MSG_TRUNC in receive
Fixed handling when skb don't fit in user buffer,
instead of returning -EMSGSIZE, the buffer is truncated (just
as unix seqpakcet does).
Signed-off-by: Sjur Braendeland <sjur.brandeland@stericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/net/caif/caif_socket.c b/net/caif/caif_socket.c
index 691a571..3d0e095 100644
--- a/net/caif/caif_socket.c
+++ b/net/caif/caif_socket.c
@@ -292,53 +292,42 @@
caif_flow_ctrl(sk, CAIF_MODEMCMD_FLOW_ON_REQ);
}
}
-/*
- * Copied from sock.c:sock_queue_rcv_skb(), and added check that user buffer
- * has sufficient size.
- */
+/*
+ * Copied from unix_dgram_recvmsg, but removed credit checks,
+ * changed locking, address handling and added MSG_TRUNC.
+ */
static int caif_seqpkt_recvmsg(struct kiocb *iocb, struct socket *sock,
- struct msghdr *m, size_t buf_len, int flags)
+ struct msghdr *m, size_t len, int flags)
{
struct sock *sk = sock->sk;
struct sk_buff *skb;
- int ret = 0;
- int len;
+ int ret;
+ int copylen;
- if (unlikely(!buf_len))
- return -EINVAL;
+ ret = -EOPNOTSUPP;
+ if (m->msg_flags&MSG_OOB)
+ goto read_error;
skb = skb_recv_datagram(sk, flags, 0 , &ret);
if (!skb)
goto read_error;
-
- len = skb->len;
-
- if (skb && skb->len > buf_len && !(flags & MSG_PEEK)) {
- len = buf_len;
- /*
- * Push skb back on receive queue if buffer too small.
- * This has a built-in race where multi-threaded receive
- * may get packet in wrong order, but multiple read does
- * not really guarantee ordered delivery anyway.
- * Let's optimize for speed without taking locks.
- */
-
- skb_queue_head(&sk->sk_receive_queue, skb);
- ret = -EMSGSIZE;
- goto read_error;
+ copylen = skb->len;
+ if (len < copylen) {
+ m->msg_flags |= MSG_TRUNC;
+ copylen = len;
}
- ret = skb_copy_datagram_iovec(skb, 0, m->msg_iov, len);
+ ret = skb_copy_datagram_iovec(skb, 0, m->msg_iov, copylen);
if (ret)
- goto read_error;
+ goto out_free;
+ ret = (flags & MSG_TRUNC) ? skb->len : copylen;
+out_free:
skb_free_datagram(sk, skb);
-
caif_check_flow_release(sk);
-
- return len;
+ return ret;
read_error:
return ret;