[PATCH AUTOSEL 4.19 593/671] net/smc: receive returns without data

Sasha Levin
2020-01-16T18:37:08Z

From: Karsten Graul <kgraul@linux.ibm.com>

[ Upstream commit 882dcfe5a1785c20f45820cbe6fec4b8b647c946 ]

smc_cdc_rxed_any_close_or_senddone() is used as an end condition for the
receive loop. This conflicts with smc_cdc_msg_recv_action() which could
run in parallel and set the bits checked by
smc_cdc_rxed_any_close_or_senddone() before the receive is processed.
In that case we could return from receive with no data, although data is
available. The same applies to smc_rx_wait().
Fix this by checking for RCV_SHUTDOWN only, which is set in
smc_cdc_msg_recv_action() after the receive was actually processed.

Fixes: 952310ccf2d8 ("smc: receive data from RMBE")
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
net/smc/smc_rx.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/net/smc/smc_rx.c b/net/smc/smc_rx.c
index bbcf0fe4ae10..1ee5fdbf8284 100644
--- a/net/smc/smc_rx.c
+++ b/net/smc/smc_rx.c
@@ -212,8 +212,7 @@ int smc_rx_wait(struct smc_sock *smc, long *timeo,
rc = sk_wait_event(sk, timeo,
sk->sk_err ||
sk->sk_shutdown & RCV_SHUTDOWN ||
- fcrit(conn) ||
- smc_cdc_rxed_any_close_or_senddone(conn),
+ fcrit(conn),
&wait);
remove_wait_queue(sk_sleep(sk), &wait);
sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
@@ -311,7 +310,6 @@ int smc_rx_recvmsg(struct smc_sock *smc, struct msghdr *msg,
smc_rx_update_cons(smc, 0);

if (sk->sk_shutdown & RCV_SHUTDOWN ||
- smc_cdc_rxed_any_close_or_senddone(conn) ||
conn->local_tx_ctrl.conn_state_flags.peer_conn_abort)
break;

--
2.20.1