RDS-TCP: Set up MSG_MORE and MSG_SENDPAGE_NOTLAST as appropriate in rds_tcp_

Backport of upstream commit 76b29ef120f5 ("RDS-TCP: Set up MSG_MORE and
MSG_SENDPAGE_NOTLAST as appropriate in rds_tcp_xmit")

For the same reasons as commit 2f5338442425 ("tcp: allow splice() to
build full TSO packets") and commit 35f9c09fe9c7 ("tcp: tcp_sendpages()
should call tcp_push() once"), rds_tcp_xmit may have multiple pages to
send, so use the MSG_MORE and MSG_SENDPAGE_NOTLAST as hints to
tcp_sendpage()

Orabug: 22012202

Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
Signed-off-by: Mukesh Kacker <mukesh.kacker@oracle.com>

diff --git a/net/rds/tcp_send.c b/net/rds/tcp_send.c
index 850a2cfb82521f099ef58d00515a9102f9b1d6f3..e9cffe0220f7e328812874657e6a08000a66f594 100644 (file)
--- a/net/rds/tcp_send.c
+++ b/net/rds/tcp_send.c
@@ -83,6 +83,7 @@ int rds_tcp_xmit(struct rds_connection *conn, struct rds_message *rm,
        struct rds_tcp_connection *tc = conn->c_transport_data;
        int done = 0;
        int ret = 0;
+       int more;
 
        if (hdr_off == 0) {
                /*
@@ -116,12 +117,15 @@ int rds_tcp_xmit(struct rds_connection *conn, struct rds_message *rm,
                        goto out;
        }
 
+       more = rm->data.op_nents > 1 ? (MSG_MORE | MSG_SENDPAGE_NOTLAST) : 0;
        while (sg < rm->data.op_nents) {
+               int flags = MSG_DONTWAIT | MSG_NOSIGNAL | more;
+
                ret = tc->t_sock->ops->sendpage(tc->t_sock,
                                                sg_page(&rm->data.op_sg[sg]),
                                                rm->data.op_sg[sg].offset + off,
                                                rm->data.op_sg[sg].length - off,
-                                               MSG_DONTWAIT|MSG_NOSIGNAL);
+                                               flags);
                rdsdebug("tcp sendpage %p:%u:%u ret %d\n", (void *)sg_page(&rm->data.op_sg[sg]),
                         rm->data.op_sg[sg].offset + off, rm->data.op_sg[sg].length - off,
                         ret);
@@ -134,6 +138,8 @@ int rds_tcp_xmit(struct rds_connection *conn, struct rds_message *rm,
                        off = 0;
                        sg++;
                }
+               if (sg == rm->data.op_nents - 1)
+                       more = 0;
        }
 
 out: