rds: avoid unenecessary cong_update in loop transport

commit f1693c63ab133d16994cc50f773982b5905af264 upstream.

Loop transport which is self loopback, remote port congestion
update isn't relevant. Infact the xmit path already ignores it.
Receive path needs to do the same.

Reported-by: syzbot+4c20b3866171ce8441d2@syzkaller.appspotmail.com
Reviewed-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/net/rds/loop.c b/net/rds/loop.c
index f2bf78de5688a3ee44862fe158bffee4ca94d91a..dac6218a460ed4d4a5b7b03ad4f6056a68784a16 100644 (file)
--- a/net/rds/loop.c
+++ b/net/rds/loop.c
@@ -193,4 +193,5 @@ struct rds_transport rds_loop_transport = {
        .inc_copy_to_user       = rds_message_inc_copy_to_user,
        .inc_free               = rds_loop_inc_free,
        .t_name                 = "loopback",
+       .t_type                 = RDS_TRANS_LOOP,
 };

diff --git a/net/rds/rds.h b/net/rds/rds.h
index 30a51fec0f63125a71c91538841ea0627500f431..edfc3397aa24f521875f01c9b683589120151d73 100644 (file)
--- a/net/rds/rds.h
+++ b/net/rds/rds.h
@@ -440,6 +440,11 @@ struct rds_notifier {
        int                     n_status;
 };
 
+/* Available as part of RDS core, so doesn't need to participate
+ * in get_preferred transport etc
+ */
+#define        RDS_TRANS_LOOP  3
+
 /**
  * struct rds_transport -  transport specific behavioural hooks
  *

diff --git a/net/rds/recv.c b/net/rds/recv.c
index cbfabdf3ff481c6b664bd06c53f22d26e65f1416..f16ee1b13b8d6cddeecaa64f8da7651527a4aff2 100644 (file)
--- a/net/rds/recv.c
+++ b/net/rds/recv.c
@@ -94,6 +94,11 @@ static void rds_recv_rcvbuf_delta(struct rds_sock *rs, struct sock *sk,
                return;
 
        rs->rs_rcv_bytes += delta;
+
+       /* loop transport doesn't send/recv congestion updates */
+       if (rs->rs_transport->t_type == RDS_TRANS_LOOP)
+               return;
+
        now_congested = rs->rs_rcv_bytes > rds_sk_rcvbuf(rs);
 
        rdsdebug("rs %p (%pI4:%u) recv bytes %d buf %d "