On Mon, Jan 19, 2026 at 05:19:13PM +0100, Laurent Vivier wrote:
Register both splice connection sockets with epoll using empty events (events=0) in tcp_splice_connect(), before initiating the connection.
This allows tcp_splice_epoll_ctl() to always use EPOLL_CTL_MOD, removing the need to check whether fds are already registered. As a result, the conditional ADD/MOD logic is no longer needed, simplifying the function.
If the second flow_epoll_set() fails after the first succeeds, we don't need explicit rollback: tcp_splice_conn_from_sock() sets the CLOSING flag on error, and conn_flag() handles it by calling epoll_del() for both sockets.
Signed-off-by: Laurent Vivier
Reviewed-by: David Gibson
--- tcp_splice.c | 20 ++++++++++---------- 1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/tcp_splice.c b/tcp_splice.c index a7c04ca8652a..cb81e012ee4b 100644 --- a/tcp_splice.c +++ b/tcp_splice.c @@ -142,20 +142,12 @@ static uint32_t tcp_splice_conn_epoll_events(uint16_t events, unsigned sidei) static int tcp_splice_epoll_ctl(struct tcp_splice_conn *conn) { uint32_t events[2]; - int m; - - if (flow_in_epoll(&conn->f)) { - m = EPOLL_CTL_MOD; - } else { - flow_epollid_set(&conn->f, EPOLLFD_ID_DEFAULT); - m = EPOLL_CTL_ADD; - }
events[0] = tcp_splice_conn_epoll_events(conn->events, 0); events[1] = tcp_splice_conn_epoll_events(conn->events, 1);
- if (flow_epoll_set(&conn->f, m, events[0], conn->s[0], 0) || - flow_epoll_set(&conn->f, m, events[1], conn->s[1], 1)) { + if (flow_epoll_set(&conn->f, EPOLL_CTL_MOD, events[0], conn->s[0], 0) || + flow_epoll_set(&conn->f, EPOLL_CTL_MOD, events[1], conn->s[1], 1)) { int ret = -errno; flow_perror(conn, "ERROR on epoll_ctl()"); return ret; @@ -368,6 +360,14 @@ static int tcp_splice_connect(const struct ctx *c, struct tcp_splice_conn *conn)
pif_sockaddr(c, &sa, tgtpif, &tgt->eaddr, tgt->eport);
+ flow_epollid_set(&conn->f, EPOLLFD_ID_DEFAULT); + if (flow_epoll_set(&conn->f, EPOLL_CTL_ADD, 0, conn->s[0], 0) || + flow_epoll_set(&conn->f, EPOLL_CTL_ADD, 0, conn->s[1], 1)) { + int ret = -errno; + flow_perror(conn, "Cannot register to epollfd"); + return ret; + } + conn_event(conn, SPLICE_CONNECT);
if (connect(conn->s[1], &sa.sa, socklen_inany(&sa))) { -- 2.52.0
-- David Gibson (he or they) | I'll have my music baroque, and my code david AT gibson.dropbear.id.au | minimalist, thank you, not the other way | around. http://www.ozlabs.org/~dgibson