Revert "macvtap: remove useless codes in macvtap_aio_read() and macvtap_recvmsg()"

This reverts commit 41e4af69a5984a3193ba3108fb4e067b0e34dc73.

MSG_TRUNC handling was broken and is going to be fixed in the
'net' tree, so revert this.

Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 5 insertions, 0 deletions

diff --git a/drivers/net/macvtap.c b/drivers/net/macvtap.c
index 2aa5e973ef17..4a34bcb6549f 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/macvtap.c
@@ -871,6 +871,7 @@ static ssize_t macvtap_aio_read(struct kiocb *iocb, const struct iovec *iv,
         }
 
         ret = macvtap_do_read(q, iv, len, file->f_flags & O_NONBLOCK);
+        ret = min_t(ssize_t, ret, len); /* XXX copied from tun.c. Why? */
         if (ret > 0)
                 iocb->ki_pos = ret;
 out:
@@ -1105,6 +1106,10 @@ static int macvtap_recvmsg(struct kiocb *iocb, struct socket *sock,
                 return -EINVAL;
         ret = macvtap_do_read(q, m->msg_iov, total_len,
                           flags & MSG_DONTWAIT);
+        if (ret > total_len) {
+                m->msg_flags |= MSG_TRUNC;
+                ret = flags & MSG_TRUNC ? ret : total_len;
+        }
         return ret;
 }