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net/smc: receive pending data after RCV_SHUTDOWN 

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: 952310ccf2 ("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>
This commit is contained in:
Karsten Graul 2019-10-10 10:16:11 +02:00 committed by Jakub Kicinski
parent 882dcfe5a1
commit 107529e31a
1 changed files with 20 additions and 5 deletions
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25
net/smc/smc_rx.c
View File

@ -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 ||