[PATCH 5/7] flow: Use epoll_id_to_fd[EPOLLFD_ID_DEFAULT] in flow_epollid_set()

[Laurent Vivier <lvivier@redhat.com>]

In tcp_epoll_ctl() and tcp_splice_epoll_ctl(), flow_epollid_set() is
called after flow_epoll_set() to set the epollid to EPOLLFD_ID_DEFAULT.
When updating an existing flow (EPOLL_CTL_MOD), flow_epoll_set() already
retrieves the correct epoll fd via flow_epollfd().  For new additions
(EPOLL_CTL_ADD), we can use epoll_id_to_fd[EPOLLFD_ID_DEFAULT] directly
instead of c->epollfd, since that's the epollid that will be set.

This removes the need for the ctx parameter from flow_epoll_set() and
simplifies the API.  The change cascades through all callers: tcp.c,
icmp.c, udp_flow.c, and tcp_splice.c.

In tcp_splice.c, removing ctx from flow_epoll_set() calls allows us to
also remove the ctx parameter from tcp_splice_epoll_ctl() and
conn_event_do(), further simplifying the splice connection handling.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 flow.c       |  8 +++-----
 flow.h       |  5 ++---
 icmp.c       |  2 +-
 tcp.c        |  6 +++---
 tcp_splice.c | 32 ++++++++++++++------------------
 udp_flow.c   |  2 +-
 6 files changed, 24 insertions(+), 31 deletions(-)

diff --git a/flow.c b/flow.c
index 9c98102e3616..a3f75015a078 100644
--- a/flow.c
+++ b/flow.c
@@ -393,7 +393,6 @@ void flow_epollid_clear(struct flow_common *f)
 
 /**
  * flow_epoll_set() - Add or modify epoll registration for a flow socket
- * @c:		Execution context
  * @type:	epoll type
  * @f:		Flow to register socket for
  * @events:	epoll events to watch for
@@ -402,9 +401,8 @@ void flow_epollid_clear(struct flow_common *f)
  *
  * Return: 0 on success, -1 on error (from epoll_ctl())
  */
-int flow_epoll_set(const struct ctx *c, enum epoll_type type,
-		   const struct flow_common *f, uint32_t events, int fd,
-		   unsigned int sidei)
+int flow_epoll_set(enum epoll_type type, const struct flow_common *f,
+		   uint32_t events, int fd, unsigned int sidei)
 {
 	struct epoll_event ev;
 	union epoll_ref ref;
@@ -423,7 +421,7 @@ int flow_epoll_set(const struct ctx *c, enum epoll_type type,
 			epollfd = flow_epollfd(f);
 		} else {
 			m = EPOLL_CTL_ADD;
-			epollfd = c->epollfd;
+			epollfd = epoll_id_to_fd[EPOLLFD_ID_DEFAULT];
 		}
 		break;
 	case EPOLL_TYPE_TCP_TIMER: {
diff --git a/flow.h b/flow.h
index 388fab124238..9740ede8963e 100644
--- a/flow.h
+++ b/flow.h
@@ -265,9 +265,8 @@ bool flow_in_epoll(const struct flow_common *f);
 int flow_epollfd(const struct flow_common *f);
 void flow_epollid_set(struct flow_common *f, int epollid);
 void flow_epollid_clear(struct flow_common *f);
-int flow_epoll_set(const struct ctx *c, enum epoll_type type,
-		   const struct flow_common *f, uint32_t events, int fd,
-		   unsigned int sidei);
+int flow_epoll_set(enum epoll_type type, const struct flow_common *f,
+		   uint32_t events, int fd, unsigned int sidei);
 void flow_epollid_register(int epollid, int epollfd);
 void flow_defer_handler(const struct ctx *c, const struct timespec *now);
 int flow_migrate_source_early(struct ctx *c, const struct migrate_stage *stage,
diff --git a/icmp.c b/icmp.c
index 235759567060..f0b6fcff1776 100644
--- a/icmp.c
+++ b/icmp.c
@@ -210,7 +210,7 @@ static struct icmp_ping_flow *icmp_ping_new(const struct ctx *c,
 		goto cancel;
 
 	flow_epollid_set(&pingf->f, EPOLLFD_ID_DEFAULT);
-	if (flow_epoll_set(c, EPOLL_TYPE_PING, &pingf->f, EPOLLIN, pingf->sock,
+	if (flow_epoll_set(EPOLL_TYPE_PING, &pingf->f, EPOLLIN, pingf->sock,
 			   TGTSIDE) < 0) {
 		close(pingf->sock);
 		goto cancel;
diff --git a/tcp.c b/tcp.c
index 2907af282551..ec4f6d2ecc04 100644
--- a/tcp.c
+++ b/tcp.c
@@ -543,14 +543,14 @@ static int tcp_epoll_ctl(const struct ctx *c, struct tcp_tap_conn *conn)
 
 	events = tcp_conn_epoll_events(conn->events, conn->flags);
 
-	if (flow_epoll_set(c, EPOLL_TYPE_TCP, &conn->f, events, conn->sock,
+	if (flow_epoll_set(EPOLL_TYPE_TCP, &conn->f, events, conn->sock,
 			   !TAPSIDE(conn)))
 		return -errno;
 
 	flow_epollid_set(&conn->f, EPOLLFD_ID_DEFAULT);
 
 	if (conn->timer != -1) {
-		if (flow_epoll_set(c, EPOLL_TYPE_TCP_TIMER, &conn->f,
+		if (flow_epoll_set(EPOLL_TYPE_TCP_TIMER, &conn->f,
 				   EPOLLIN | EPOLLET, conn->timer, 0))
 			return -errno;
 	}
@@ -582,7 +582,7 @@ static void tcp_timer_ctl(const struct ctx *c, struct tcp_tap_conn *conn)
 			return;
 		}
 
-		if (flow_epoll_set(c, EPOLL_TYPE_TCP_TIMER, &conn->f,
+		if (flow_epoll_set(EPOLL_TYPE_TCP_TIMER, &conn->f,
 				   EPOLLIN | EPOLLET, fd, 0)) {
 			flow_dbg_perror(conn, "failed to add timer");
 			close(fd);
diff --git a/tcp_splice.c b/tcp_splice.c
index 7367f435367b..ccf627f4427d 100644
--- a/tcp_splice.c
+++ b/tcp_splice.c
@@ -135,22 +135,20 @@ static uint32_t tcp_splice_conn_epoll_events(uint16_t events, unsigned sidei)
 
 /**
  * tcp_splice_epoll_ctl() - Add/modify/delete epoll state from connection events
- * @c:		Execution context
  * @conn:	Connection pointer
  *
  * Return: 0 on success, negative error code on failure (not on deletion)
  */
-static int tcp_splice_epoll_ctl(const struct ctx *c,
-				struct tcp_splice_conn *conn)
+static int tcp_splice_epoll_ctl(struct tcp_splice_conn *conn)
 {
 	uint32_t events[2];
 
 	events[0] = tcp_splice_conn_epoll_events(conn->events, 0);
 	events[1] = tcp_splice_conn_epoll_events(conn->events, 1);
 
-	if (flow_epoll_set(c, EPOLL_TYPE_TCP_SPLICE, &conn->f, events[0],
+	if (flow_epoll_set(EPOLL_TYPE_TCP_SPLICE, &conn->f, events[0],
 			   conn->s[0], 0) ||
-	    flow_epoll_set(c, EPOLL_TYPE_TCP_SPLICE, &conn->f, events[1],
+	    flow_epoll_set(EPOLL_TYPE_TCP_SPLICE, &conn->f, events[1],
 			   conn->s[1], 1)) {
 		int ret = -errno;
 		flow_perror(conn, "ERROR on epoll_ctl()");
@@ -204,12 +202,10 @@ static void conn_flag_do(struct tcp_splice_conn *conn,
 
 /**
  * conn_event_do() - Set and log connection events, update epoll state
- * @c:		Execution context
  * @conn:	Connection pointer
  * @event:	Connection event
  */
-static void conn_event_do(const struct ctx *c, struct tcp_splice_conn *conn,
-			  unsigned long event)
+static void conn_event_do(struct tcp_splice_conn *conn, unsigned long event)
 {
 	if (event & (event - 1)) {
 		int flag_index = fls(~event);
@@ -231,14 +227,14 @@ static void conn_event_do(const struct ctx *c, struct tcp_splice_conn *conn,
 			flow_dbg(conn, "%s", tcp_splice_event_str[flag_index]);
 	}
 
-	if (tcp_splice_epoll_ctl(c, conn))
+	if (tcp_splice_epoll_ctl(conn))
 		conn_flag(c, conn, CLOSING);
 }
 
-#define conn_event(c, conn, event)					\
+#define conn_event(conn, event)					\
 	do {								\
 		flow_trace(conn, "event at %s:%i",__func__, __LINE__);	\
-		conn_event_do(c, conn, event);				\
+		conn_event_do(conn, event);				\
 	} while (0)
 
 
@@ -320,7 +316,7 @@ static int tcp_splice_connect_finish(const struct ctx *c,
 	}
 
 	if (!(conn->events & SPLICE_ESTABLISHED))
-		conn_event(c, conn, SPLICE_ESTABLISHED);
+		conn_event(conn, SPLICE_ESTABLISHED);
 
 	return 0;
 }
@@ -367,7 +363,7 @@ static int tcp_splice_connect(const struct ctx *c, struct tcp_splice_conn *conn)
 
 	pif_sockaddr(c, &sa, tgtpif, &tgt->eaddr, tgt->eport);
 
-	conn_event(c, conn, SPLICE_CONNECT);
+	conn_event(conn, SPLICE_CONNECT);
 
 	if (connect(conn->s[1], &sa.sa, socklen_inany(&sa))) {
 		if (errno != EINPROGRESS) {
@@ -376,7 +372,7 @@ static int tcp_splice_connect(const struct ctx *c, struct tcp_splice_conn *conn)
 			return -errno;
 		}
 	} else {
-		conn_event(c, conn, SPLICE_ESTABLISHED);
+		conn_event(conn, SPLICE_ESTABLISHED);
 		return tcp_splice_connect_finish(c, conn);
 	}
 
@@ -485,14 +481,14 @@ void tcp_splice_sock_handler(struct ctx *c, union epoll_ref ref,
 
 	if (events & EPOLLOUT) {
 		fromsidei = !evsidei;
-		conn_event(c, conn, ~OUT_WAIT(evsidei));
+		conn_event(conn, ~OUT_WAIT(evsidei));
 	} else {
 		fromsidei = evsidei;
 	}
 
 	if (events & EPOLLRDHUP)
 		/* For side 0 this is fake, but implied */
-		conn_event(c, conn, FIN_RCVD(evsidei));
+		conn_event(conn, FIN_RCVD(evsidei));
 
 swap:
 	eof = 0;
@@ -574,7 +570,7 @@ retry:
 			if (conn->read[fromsidei] == conn->written[fromsidei])
 				break;
 
-			conn_event(c, conn, OUT_WAIT(!fromsidei));
+			conn_event(conn, OUT_WAIT(!fromsidei));
 			break;
 		}
 
@@ -596,7 +592,7 @@ retry:
 			if ((conn->events & FIN_RCVD(sidei)) &&
 			    !(conn->events & FIN_SENT(!sidei))) {
 				shutdown(conn->s[!sidei], SHUT_WR);
-				conn_event(c, conn, FIN_SENT(!sidei));
+				conn_event(conn, FIN_SENT(!sidei));
 			}
 		}
 	}
diff --git a/udp_flow.c b/udp_flow.c
index 42f3622d621c..07ff589670c1 100644
--- a/udp_flow.c
+++ b/udp_flow.c
@@ -84,7 +84,7 @@ static int udp_flow_sock(const struct ctx *c,
 	}
 
 	flow_epollid_set(&uflow->f, EPOLLFD_ID_DEFAULT);
-	rc = flow_epoll_set(c, EPOLL_TYPE_UDP, &uflow->f, EPOLLIN, s, sidei);
+	rc = flow_epoll_set(EPOLL_TYPE_UDP, &uflow->f, EPOLLIN, s, sidei);
 	if (rc < 0) {
 		close(s);
 		return rc;
-- 
2.51.1