From 572efade27c55f11436ed10bbb59ef10c6d83d93 Mon Sep 17 00:00:00 2001 From: David Howells Date: Fri, 23 Jun 2023 23:55:02 +0100 Subject: [PATCH] rds: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage When transmitting data, call down into TCP using a single sendmsg with MSG_SPLICE_PAGES to indicate that content should be spliced. To make this work, the data is assembled in a bio_vec array and attached to a BVEC-type iterator. Signed-off-by: David Howells cc: Santosh Shilimkar cc: Jens Axboe cc: Matthew Wilcox cc: rds-devel@oss.oracle.com Link: https://lore.kernel.org/r/20230623225513.2732256-6-dhowells@redhat.com Signed-off-by: Jakub Kicinski --- net/rds/tcp_send.c | 21 +++++++++++---------- 1 file changed, 11 insertions(+), 10 deletions(-) diff --git a/net/rds/tcp_send.c b/net/rds/tcp_send.c index 8c4d1d6e9249..7d284ac7e81a 100644 --- a/net/rds/tcp_send.c +++ b/net/rds/tcp_send.c @@ -72,9 +72,10 @@ int rds_tcp_xmit(struct rds_connection *conn, struct rds_message *rm, { struct rds_conn_path *cp = rm->m_inc.i_conn_path; struct rds_tcp_connection *tc = cp->cp_transport_data; + struct msghdr msg = {}; + struct bio_vec bvec; int done = 0; int ret = 0; - int more; if (hdr_off == 0) { /* @@ -111,15 +112,17 @@ 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; + msg.msg_flags = MSG_SPLICE_PAGES | MSG_DONTWAIT | MSG_NOSIGNAL; + if (sg + 1 < rm->data.op_nents) + msg.msg_flags |= MSG_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, - flags); + bvec_set_page(&bvec, sg_page(&rm->data.op_sg[sg]), + rm->data.op_sg[sg].length - off, + rm->data.op_sg[sg].offset + off); + iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bvec, 1, + rm->data.op_sg[sg].length - off); + ret = sock_sendmsg(tc->t_sock, &msg); 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); @@ -132,8 +135,6 @@ 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: