[PATCH 5/8] flow: Make flow timer per-caller for thread safety

[Laurent Vivier <lvivier@redhat.com>]

Move the static flow_timer_run variable out of flow.c and pass it as a
parameter to flow_defer_handler().  This allows each caller to maintain
its own timer state: each vhost-user queue pair worker uses the per-qpair
context.

Signed-off-by: Laurent Vivier <lvivier@redhat.com>
---
 flow.c  | 11 +++++------
 flow.h  |  2 +-
 passt.c |  8 +++++---
 3 files changed, 11 insertions(+), 10 deletions(-)

diff --git a/flow.c b/flow.c
index 787a7139cfc1..08c7620c7b0f 100644
--- a/flow.c
+++ b/flow.c
@@ -142,9 +142,6 @@ static flow_sidx_t flow_hashtab[FLOW_HASH_SIZE];
 static_assert(ARRAY_SIZE(flow_hashtab) >= 2 * FLOW_MAX,
 "Safe linear probing requires hash table with more entries than the number of sides in the flow table");
 
-/* Last time the flow timers ran */
-static struct timespec flow_timer_run;
-
 /** flowside_from_af() - Initialise flowside from addresses
  * @side:	flowside to initialise
  * @af:		Address family (AF_INET or AF_INET6)
@@ -898,9 +895,11 @@ flow_sidx_t flow_lookup_sa(const struct ctx *c, uint8_t proto, uint8_t pif,
  * flow_defer_handler() - Handler for per-flow deferred and timed tasks
  * @c:		Execution context
  * @now:	Current timestamp
+ * @timer_run:	Last time the flow timers ran
+ * @qpair:	Queue pair to process
  */
 void flow_defer_handler(const struct ctx *c, const struct timespec *now,
-			unsigned int qpair)
+			struct timespec *timer_run, unsigned int qpair)
 {
 	struct flow_free_cluster *free_head = NULL;
 	unsigned *last_next = &flow_first_free;
@@ -908,9 +907,9 @@ void flow_defer_handler(const struct ctx *c, const struct timespec *now,
 	bool timer = false;
 	union flow *flow;
 
-	if (timespec_diff_ms(now, &flow_timer_run) >= FLOW_TIMER_INTERVAL) {
+	if (timespec_diff_ms(now, timer_run) >= FLOW_TIMER_INTERVAL) {
 		timer = true;
-		flow_timer_run = *now;
+		*timer_run = *now;
 	}
 
 	assert(!flow_new_entry); /* Incomplete flow at end of cycle */
diff --git a/flow.h b/flow.h
index 53e0408a9ee5..10634e64a7fc 100644
--- a/flow.h
+++ b/flow.h
@@ -280,7 +280,7 @@ void flow_migrate(struct flow_common *f, unsigned int qpair, uint32_t events,
 	(flow_migrate(&(flow_)->f, qpair_, events_, fd_, sidei_))
 
 void flow_defer_handler(const struct ctx *c, const struct timespec *now,
-			unsigned int qpair);
+			struct timespec *timer_run, unsigned int qpair);
 int flow_migrate_source_early(struct ctx *c, const struct migrate_stage *stage,
 			      int fd);
 int flow_migrate_source_pre(struct ctx *c, const struct migrate_stage *stage,
diff --git a/passt.c b/passt.c
index 3afc59b19120..bebc2b99f523 100644
--- a/passt.c
+++ b/passt.c
@@ -98,15 +98,16 @@ struct passt_stats {
  * post_handler() - Run periodic and deferred tasks for L4 protocol handlers
  * @c:		Execution context
  * @now:	Current timestamp
+ * @timer_run:	Last time the flow timers ran
  * @qpair:	Queue pair to process
  */
 static void post_handler(struct ctx *c, const struct timespec *now,
-			 unsigned int qpair)
+			 struct timespec *timer_run, unsigned int qpair)
 {
 	if (!c->no_tcp)
 		tcp_defer_handler(c, now, qpair);
 
-	flow_defer_handler(c, now, qpair);
+	flow_defer_handler(c, now, timer_run, qpair);
 	fwd_scan_ports_timer(c, now);
 
 	if (!c->no_ndp)
@@ -221,6 +222,7 @@ static void print_stats(const struct ctx *c, const struct passt_stats *stats,
 static void passt_worker(void *opaque, int nfds, struct epoll_event *events)
 {
 	static struct passt_stats stats = { 0 };
+	static struct timespec flow_timer_run;
 	struct ctx *c = opaque;
 	struct timespec now;
 	int i;
@@ -304,7 +306,7 @@ static void passt_worker(void *opaque, int nfds, struct epoll_event *events)
 		print_stats(c, &stats, &now);
 	}
 
-	post_handler(c, &now, QPAIR_DEFAULT);
+	post_handler(c, &now, &flow_timer_run, QPAIR_DEFAULT);
 
 	migrate_handler(c);
 }
-- 
2.54.0