The function tcp_splice_conn_epoll_events() currently takes an array of
struct epoll_event and fills in the .events field for both sides using
flow_foreach_sidei() loops.
This works, but the function is doing two conceptually separate things
at once: computing events for side 0 and computing events for side 1.
The OUT_WAIT handling is particularly subtle, as it has cross-side
effects: when OUT_WAIT(sidei) is set, we add EPOLLOUT to ev[sidei] but
also remove EPOLLIN from ev[!sidei].
Refactor to make the function compute events for a single side at a
time, taking sidei as a parameter and returning uint32_t. This makes
the logic more focused and easier to follow. The cross-side effects of
OUT_WAIT are preserved by checking both OUT_WAIT(sidei) and
OUT_WAIT(!sidei) within each call.
The caller tcp_splice_epoll_ctl() now invokes the function twice, once
for each side, making the two-sided nature of the operation explicit.
No functional change.
Signed-off-by: Laurent Vivier
Reviewed-by: David Gibson
---
tcp_splice.c | 33 ++++++++++++++-------------------
1 file changed, 14 insertions(+), 19 deletions(-)
diff --git a/tcp_splice.c b/tcp_splice.c
index 440522449c13..bf4ff466de07 100644
--- a/tcp_splice.c
+++ b/tcp_splice.c
@@ -114,29 +114,23 @@ static struct tcp_splice_conn *conn_at_sidx(flow_sidx_t sidx)
* @events: Connection event flags
* @ev: Events to fill in, 0 is accepted socket, 1 is connecting socket
*/
-static void tcp_splice_conn_epoll_events(uint16_t events,
- struct epoll_event ev[])
+static uint32_t tcp_splice_conn_epoll_events(uint16_t events, unsigned sidei)
{
- unsigned sidei;
-
- flow_foreach_sidei(sidei)
- ev[sidei].events = 0;
+ uint32_t e = 0;
if (events & SPLICE_ESTABLISHED) {
- flow_foreach_sidei(sidei) {
- if (!(events & FIN_SENT(!sidei)))
- ev[sidei].events = EPOLLIN | EPOLLRDHUP;
- }
- } else if (events & SPLICE_CONNECT) {
- ev[1].events = EPOLLOUT;
+ if (!(events & FIN_SENT(!sidei)))
+ e = EPOLLIN | EPOLLRDHUP;
+ } else if (sidei == 1 && events & SPLICE_CONNECT) {
+ e = EPOLLOUT;
}
- flow_foreach_sidei(sidei) {
- if (events & OUT_WAIT(sidei)) {
- ev[sidei].events |= EPOLLOUT;
- ev[!sidei].events &= ~EPOLLIN;
- }
- }
+ if (events & OUT_WAIT(sidei))
+ e |= EPOLLOUT;
+ if (events & OUT_WAIT(!sidei))
+ e &= ~EPOLLIN;
+
+ return e;
}
/**
@@ -161,7 +155,8 @@ static int tcp_splice_epoll_ctl(const struct ctx *c,
struct epoll_event ev[SIDES] = { { .data.u64 = ref[0].u64 },
{ .data.u64 = ref[1].u64 } };
- tcp_splice_conn_epoll_events(conn->events, ev);
+ ev[0].events = tcp_splice_conn_epoll_events(conn->events, 0);
+ ev[1].events = tcp_splice_conn_epoll_events(conn->events, 1);
if (epoll_ctl(epollfd, m, conn->s[0], &ev[0]) ||
--
2.52.0