[PATCH net-next v2] tipc: failed transmissions should return error

[<erik.hugne@ericsson.com>]

From: Erik Hugne <erik.hugne@ericsson.com>

When a message could not be sent out because the destination node
or link could not be found, the full message size is returned from
sendmsg() as if it had been sent successfully. An application will
then get a false indication that it's making forward progress. This
problem has existed since the initial commit in 2.6.16.

We change this to return -ENETUNREACH if the message cannot be
delivered due to the destination node/link being unavailable. We
also get rid of the redundant tipc_reject_msg call since freeing
the buffer and doing a tipc_port_iovec_reject accomplishes exactly
the same thing.

Signed-off-by: Erik Hugne <erik.hugne@ericsson.com>
Reviewed-by: Jon Maloy <jon.maloy@ericsson.com>
---
v2: Respin on top of 247f0f3c3176c55b46cb9a20011d3d6757634815 
tipc: align tipc function names with common naming practice in the network

 net/tipc/link.c |   14 ++++++--------
 1 file changed, 6 insertions(+), 8 deletions(-)

diff --git a/net/tipc/link.c b/net/tipc/link.c
index e4f233d..e998dba 100644
--- a/net/tipc/link.c
+++ b/net/tipc/link.c
@@ -1020,12 +1020,9 @@ exit:
 	read_unlock_bh(&tipc_net_lock);
 
 	/* Couldn't find a link to the destination node */
-	if (buf)
-		return tipc_reject_msg(buf, TIPC_ERR_NO_NODE);
-	if (res >= 0)
-		return tipc_port_iovec_reject(sender, hdr, msg_sect, len,
-					      TIPC_ERR_NO_NODE);
-	return res;
+	kfree_skb(buf);
+	tipc_port_iovec_reject(sender, hdr, msg_sect, len, TIPC_ERR_NO_NODE);
+	return -ENETUNREACH;
 }
 
 /*
@@ -1163,8 +1160,9 @@ error:
 	} else {
 reject:
 		kfree_skb_list(buf_chain);
-		return tipc_port_iovec_reject(sender, hdr, msg_sect,
-					      len, TIPC_ERR_NO_NODE);
+		tipc_port_iovec_reject(sender, hdr, msg_sect, len,
+				       TIPC_ERR_NO_NODE);
+		return -ENETUNREACH;
 	}
 
 	/* Append chain of fragments to send queue & send them */
-- 
1.7.9.5