rds: avoid unenecessary cong_update in loop transport

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>

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 b04c333d9d1c201ba4aa4617c750941cf4cdfec7..f2272fb8cd456e7b5bb2495d5d02691803c3769f 100644 (file)
--- a/net/rds/rds.h
+++ b/net/rds/rds.h
@@ -479,6 +479,11 @@ 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 dc67458b52f0043c2328d4a77a43536e7c62b0ed..192ac6f78ded7b0288ac01d641cd5f7772b03fd8 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 "