This patch is to add support for MSG_MORE on sctp. It adds force_delay in sctp_datamsg to save MSG_MORE, and sets it after creating datamsg according to the send flag. sctp_packet_can_append_data then uses it to decide if the chunks of this msg will be sent at once or delay it.
Note that unlike [1], this patch saves MSG_MORE in datamsg, instead of in assoc. As sctp enqueues the chunks first, then dequeue them one by one. If it's saved in assoc,the current msg's send flag (MSG_MORE) may affect other chunks' bundling. Since last patch, sctp flush out queue once assoc state falls into SHUTDOWN_PENDING, the close block problem mentioned in [1] has been solved as well. [1] https://patchwork.ozlabs.org/patch/372404/ Signed-off-by: Xin Long <lucien....@gmail.com> --- include/net/sctp/structs.h | 1 + net/sctp/output.c | 9 +++------ net/sctp/socket.c | 1 + 3 files changed, 5 insertions(+), 6 deletions(-) diff --git a/include/net/sctp/structs.h b/include/net/sctp/structs.h index 387c802..a244db5 100644 --- a/include/net/sctp/structs.h +++ b/include/net/sctp/structs.h @@ -497,6 +497,7 @@ struct sctp_datamsg { /* Did the messenge fail to send? */ int send_error; u8 send_failed:1, + force_delay:1, can_delay; /* should this message be Nagle delayed */ }; diff --git a/net/sctp/output.c b/net/sctp/output.c index 814eac0..85406d5 100644 --- a/net/sctp/output.c +++ b/net/sctp/output.c @@ -704,18 +704,15 @@ static sctp_xmit_t sctp_packet_can_append_data(struct sctp_packet *packet, * unacknowledged. */ - if (sctp_sk(asoc->base.sk)->nodelay) - /* Nagle disabled */ + if ((sctp_sk(asoc->base.sk)->nodelay || inflight == 0) && + !chunk->msg->force_delay) + /* Nothing unacked */ return SCTP_XMIT_OK; if (!sctp_packet_empty(packet)) /* Append to packet */ return SCTP_XMIT_OK; - if (inflight == 0) - /* Nothing unacked */ - return SCTP_XMIT_OK; - if (!sctp_state(asoc, ESTABLISHED)) return SCTP_XMIT_OK; diff --git a/net/sctp/socket.c b/net/sctp/socket.c index 75f35ce..b532148 100644 --- a/net/sctp/socket.c +++ b/net/sctp/socket.c @@ -1964,6 +1964,7 @@ static int sctp_sendmsg(struct sock *sk, struct msghdr *msg, size_t msg_len) err = PTR_ERR(datamsg); goto out_free; } + datamsg->force_delay = !!(msg->msg_flags & MSG_MORE); /* Now send the (possibly) fragmented message. */ list_for_each_entry(chunk, &datamsg->chunks, frag_list) { -- 2.1.0
