[PATCH] examples/vhost: fix hang on exit

[Stephen Hemminger <stephen@networkplumber.org>]

destroy_device() waits for the worker lcore to ack device removal.
Since the signal handler rework, the workers exit before the vhost
drivers are unregistered, so the destroy callback spins forever.

Unregister the drivers while the workers are still polling, then
stop and join them.

Bugzilla ID: 2071
Fixes: 5ffa8fafcbd3 ("examples/vhost: make signal handler safe")
Cc: stable@dpdk.org

Reported-by: Yu Jiang <yux.jiang@intel.com>
Signed-off-by: Stephen Hemminger <stephen@networkplumber.org>
---
 examples/vhost/main.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/examples/vhost/main.c b/examples/vhost/main.c
index 523195f5c4..16c9387f8f 100644
--- a/examples/vhost/main.c
+++ b/examples/vhost/main.c
@@ -69,6 +69,8 @@ static uint32_t enabled_port_mask = 0;
 /* Set by the SIGINT handler to stop the worker loops. */
 static volatile sig_atomic_t quit;
 
+static RTE_ATOMIC(bool) stop_workers;
+
 /* Promiscuous mode */
 static uint32_t promiscuous;
 
@@ -1242,7 +1244,7 @@ switch_worker(void *arg)
 		}
 	}
 
-	while (!quit) {
+	while (!rte_atomic_load_explicit(&stop_workers, rte_memory_order_relaxed)) {
 		drain_mbuf_table(tx_q);
 		drain_vhost_table();
 		/*
-- 
2.53.0