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 f2bf78d..dac6218 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 d09f6c1..f685d8b 100644 (file)
--- a/net/rds/rds.h
+++ b/net/rds/rds.h
@@ -454,6 +454,11 @@ 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 555f07c..c27ccea 100644 (file)
--- a/net/rds/recv.c
+++ b/net/rds/recv.c
@@ -103,6 +103,11 @@ static void rds_recv_rcvbuf_delta(struct rds_sock *rs, struct sock *sk,
                rds_stats_add(s_recv_bytes_added_to_socket, delta);
        else
                rds_stats_add(s_recv_bytes_removed_from_socket, -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 "