[PATCH 4/7] flow: Delegate epoll file descriptor management to threading subsystem

[Laurent Vivier <lvivier@redhat.com>]

Remove the flow-local epoll_id_to_fd mapping array and instead
rely on the threading subsystem to provide the epoll file descriptor
for a given thread number.

Update all protocol handlers (ICMP, TCP, TCP splice, UDP).

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 flow.c  | 17 +++++++++--------
 flow.h  |  4 +---
 passt.c |  2 +-
 tcp.c   |  3 ++-
 4 files changed, 13 insertions(+), 13 deletions(-)

diff --git a/flow.c b/flow.c
index 3012a07ed680..7821b3f91285 100644
--- a/flow.c
+++ b/flow.c
@@ -24,6 +24,7 @@
 #include "repair.h"
 #include "epoll_ctl.h"
 #include "serialise.h"
+#include "threading.h"
 
 const char *flow_state_str[] = {
 	[FLOW_STATE_FREE]	= "FREE",
@@ -221,7 +222,6 @@ static_assert(ARRAY_SIZE(flow_epoll) == FLOW_NUM_TYPES,
 unsigned flow_first_free;
 union flow flowtab[FLOW_MAX];
 static _Thread_local const union flow *flow_new_entry; /* = NULL */
-int qpair_to_fd[FLOW_QPAIR_SIZE];
 
 /* Hash table to index it */
 #define FLOW_HASH_LOAD		70		/* % */
@@ -457,7 +457,12 @@ static void flow_set_state(struct flow_common *f, enum flow_state state)
  */
 int flow_epollfd(const struct flow_common *f)
 {
-	return qpair_to_fd[f->qpair];
+	/* mapping 1:1 between qpair and threadid
+	 * return threading_epollfd(f->qpair);
+	 * but for the moment we have only one thread
+	 */
+	(void)f;
+	return threading_epollfd(THREADING_ID_DEFAULT);
 }
 
 /**
@@ -525,7 +530,7 @@ bool flow_migrate_epollfd(struct flow_common *f, unsigned int qpair,
 	flow_trace((union flow *)f,
 		   "migrating from qpair %d to %d", qpair, target);
 
-	epoll_del(qpair_to_fd[qpair], ref.fd);
+	epoll_del(threading_epollfd(qpair), ref.fd);
 	flow_setqp(f, target);
 	flow_epoll_set(f, EPOLL_CTL_ADD, events, ref.fd, ref.flowside.sidei);
 	ret = true;
@@ -1444,9 +1449,8 @@ int flow_migrate_target(struct ctx *c, const struct migrate_stage *stage,
 
 /**
  * flow_init() - Initialise flow related data structures
- * @c:		Execution context
  */
-void flow_init(const struct ctx *c)
+void flow_init(void)
 {
 	unsigned b;
 
@@ -1456,7 +1460,4 @@ void flow_init(const struct ctx *c)
 
 	for (b = 0; b < FLOW_HASH_SIZE; b++)
 		flow_hashtab[b] = FLOW_SIDX_NONE;
-
-	for (b = 0; b < FLOW_QPAIR_SIZE; b++)
-		qpair_to_fd[b] = c->epollfd;
 }
diff --git a/flow.h b/flow.h
index c31a51a9cc96..e2693efd0f70 100644
--- a/flow.h
+++ b/flow.h
@@ -157,8 +157,6 @@ struct flowside {
 	in_port_t		eport;
 };
 
-extern int qpair_to_fd[];
-
 /**
  * flowside_eq() - Check if two flowsides are equal
  * @left, @right:	Flowsides to compare
@@ -266,7 +264,7 @@ flow_sidx_t flow_lookup_sa(const struct ctx *c, uint8_t proto, uint8_t pif,
 
 union flow;
 
-void flow_init(const struct ctx *c);
+void flow_init(void);
 int flow_epollfd(const struct flow_common *f);
 int flow_epoll_set(const struct flow_common *f, int command, uint32_t events,
 		   int fd, unsigned int sidei);
diff --git a/passt.c b/passt.c
index 2cedb7ba0756..57290a5a7c6e 100644
--- a/passt.c
+++ b/passt.c
@@ -399,7 +399,7 @@ int main(int argc, char **argv)
 	if (clock_gettime(CLOCK_MONOTONIC, &now))
 		die_perror("Failed to get CLOCK_MONOTONIC time");
 
-	flow_init(c);
+	flow_init();
 	fwd_scan_ports_init(c);
 
 	if ((!c->no_udp && udp_init(c)) || (!c->no_tcp && tcp_init(c)))
diff --git a/tcp.c b/tcp.c
index 2767a8494107..e8da65410bcf 100644
--- a/tcp.c
+++ b/tcp.c
@@ -317,6 +317,7 @@
 #include "tcp_buf.h"
 #include "tcp_vu.h"
 #include "epoll_ctl.h"
+#include "threading.h"
 
 /*
  * The size of TCP header (including options) is given by doff (Data Offset)
@@ -2721,7 +2722,7 @@ void tcp_timer_handler(const struct ctx *c, union epoll_ref ref,
 	assert(conn->f.type == FLOW_TCP);
 
 	if (conn->f.qpair != qpair) {
-		int old_epollfd = qpair_to_fd[qpair];
+		int old_epollfd = threading_epollfd(qpair);
 
 		epoll_del(old_epollfd, conn->timer);
 		if (tcp_timer_epoll_add(conn, conn->timer, now) < 0) {
-- 
2.54.0