From: Karsten Graul <kgraul@linux.ibm.com>
To: davem@davemloft.net
Cc: netdev@vger.kernel.org, linux-s390@vger.kernel.org,
gor@linux.ibm.com, heiko.carstens@de.ibm.com,
raspl@linux.ibm.com, ubraun@linux.ibm.com
Subject: [PATCH v2 net 3/3] net/smc: receive pending data after RCV_SHUTDOWN
Date: Thu, 10 Oct 2019 10:16:11 +0200 [thread overview]
Message-ID: <20191010081611.35446-4-kgraul@linux.ibm.com> (raw)
In-Reply-To: <20191010081611.35446-1-kgraul@linux.ibm.com>
smc_rx_recvmsg() first checks if data is available, and then if
RCV_SHUTDOWN is set. There is a race when smc_cdc_msg_recv_action() runs
in between these 2 checks, receives data and sets RCV_SHUTDOWN.
In that case smc_rx_recvmsg() would return from receive without to
process the available data.
Fix that with a final check for data available if RCV_SHUTDOWN is set.
Move the check for data into a function and call it twice.
And use the existing helper smc_rx_data_available().
Fixes: 952310ccf2d8 ("smc: receive data from RMBE")
Reviewed-by: Ursula Braun <ubraun@linux.ibm.com>
Signed-off-by: Karsten Graul <kgraul@linux.ibm.com>
---
net/smc/smc_rx.c | 25 ++++++++++++++++++++-----
1 file changed, 20 insertions(+), 5 deletions(-)
diff --git a/net/smc/smc_rx.c b/net/smc/smc_rx.c
index 000002642288..97e8369002d7 100644
--- a/net/smc/smc_rx.c
+++ b/net/smc/smc_rx.c
@@ -261,6 +261,18 @@ static int smc_rx_recv_urg(struct smc_sock *smc, struct msghdr *msg, int len,
return -EAGAIN;
}
+static bool smc_rx_recvmsg_data_available(struct smc_sock *smc)
+{
+ struct smc_connection *conn = &smc->conn;
+
+ if (smc_rx_data_available(conn))
+ return true;
+ else if (conn->urg_state == SMC_URG_VALID)
+ /* we received a single urgent Byte - skip */
+ smc_rx_update_cons(smc, 0);
+ return false;
+}
+
/* smc_rx_recvmsg - receive data from RMBE
* @msg: copy data to receive buffer
* @pipe: copy data to pipe if set - indicates splice() call
@@ -302,15 +314,18 @@ int smc_rx_recvmsg(struct smc_sock *smc, struct msghdr *msg,
if (read_done >= target || (pipe && read_done))
break;
- if (atomic_read(&conn->bytes_to_rcv))
+ if (smc_rx_recvmsg_data_available(smc))
goto copy;
- else if (conn->urg_state == SMC_URG_VALID)
- /* we received a single urgent Byte - skip */
- smc_rx_update_cons(smc, 0);
if (sk->sk_shutdown & RCV_SHUTDOWN ||
- conn->local_tx_ctrl.conn_state_flags.peer_conn_abort)
+ conn->local_tx_ctrl.conn_state_flags.peer_conn_abort) {
+ /* smc_cdc_msg_recv_action() could have run after
+ * above smc_rx_recvmsg_data_available()
+ */
+ if (smc_rx_recvmsg_data_available(smc))
+ goto copy;
break;
+ }
if (read_done) {
if (sk->sk_err ||
--
2.17.1
next prev parent reply other threads:[~2019-10-10 8:16 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-10-10 8:16 [PATCH v2 net 0/3] net/smc: fixes for -net Karsten Graul
2019-10-10 8:16 ` [PATCH v2 net 1/3] net/smc: fix SMCD link group creation with VLAN id Karsten Graul
2019-10-10 8:16 ` [PATCH v2 net 2/3] net/smc: receive returns without data Karsten Graul
2019-10-10 8:16 ` Karsten Graul [this message]
2019-10-11 2:16 ` [PATCH v2 net 0/3] net/smc: fixes for -net Jakub Kicinski
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