[PATCH 4.16 095/272] rxrpc: Fix Tx ring annotation after initial Tx failure

Greg Kroah-Hartman
2018-05-28T11:57:00Z

From: David Howells <dhowells@redhat.com>

[ Upstream commit 03877bf6a30cca7d4bc3ffabd3c3e9464a7a1a19 ]

rxrpc calls have a ring of packets that are awaiting ACK or retransmission
and a parallel ring of annotations that tracks the state of those packets.
If the initial transmission of a packet on the underlying UDP socket fails
then the packet annotation is marked for resend - but the setting of this
mark accidentally erases the last-packet mark also stored in the same
annotation slot. If this happens, a call won't switch out of the Tx phase
when all the packets have been transmitted.

Fix this by retaining the last-packet mark and only altering the packet
state.

Fixes: 248f219cb8bc ("rxrpc: Rewrite the data and ack handling code")
Signed-off-by: David Howells <dhowells@redhat.com>
Signed-off-by: Sasha Levin <alexander.levin@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
net/rxrpc/sendmsg.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

--- a/net/rxrpc/sendmsg.c
+++ b/net/rxrpc/sendmsg.c
@@ -130,7 +130,9 @@ static inline void rxrpc_instant_resend(
spin_lock_bh(&call->lock);

if (call->state < RXRPC_CALL_COMPLETE) {
- call->rxtx_annotations[ix] = RXRPC_TX_ANNO_RETRANS;
+ call->rxtx_annotations[ix] =
+ (call->rxtx_annotations[ix] & RXRPC_TX_ANNO_LAST) |
+ RXRPC_TX_ANNO_RETRANS;
if (!test_and_set_bit(RXRPC_CALL_EV_RESEND, &call->events))
rxrpc_queue_call(call);
}