[dpdk-dev] [PATCH] net/vhost: fix redundant queue state event

[Noa Ezra <noae@mellanox.com>]

In some situations, when a virtual machine is starting,
vring_state_changed can be called while there was no change in the
queue state. This fix makes sure that there was really a change in the
queue state before calling the callback for EVENT_QUEUE_STATE.

Fixes: ee584e9710b9 ("vhost: add driver on top of the library")
Cc: stable@dpdk.org
Reviewed-by: Matan Azrad <matan@mellanox.com>
---
 drivers/net/vhost/rte_eth_vhost.c | 4 ++++
 1 file changed, 4 insertions(+)

diff --git a/drivers/net/vhost/rte_eth_vhost.c b/drivers/net/vhost/rte_eth_vhost.c
index cad1e5c..fbe7a37 100644
--- a/drivers/net/vhost/rte_eth_vhost.c
+++ b/drivers/net/vhost/rte_eth_vhost.c
@@ -855,6 +855,10 @@ struct vhost_xstats_name_off {
 	/* won't be NULL */
 	state = vring_states[eth_dev->data->port_id];
 	rte_spinlock_lock(&state->lock);
+	if (state->cur[vring] == enable) {
+		rte_spinlock_unlock(&state->lock);
+		return 0;
+	}
 
 	state->cur[vring] = enable;
 	state->max_vring = RTE_MAX(vring, state->max_vring);
-- 
1.8.3.1