net/vhost: fix redundant queue state event

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
Signed-off-by: Noa Ezra <noae@mellanox.com>
Reviewed-by: Matan Azrad <matan@mellanox.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

diff --git a/drivers/net/vhost/rte_eth_vhost.c b/drivers/net/vhost/rte_eth_vhost.c
index c3ba602..5de21f1 100644 (file)
--- a/drivers/net/vhost/rte_eth_vhost.c
+++ b/drivers/net/vhost/rte_eth_vhost.c
@@ -853,6 +853,10 @@ vring_state_changed(int vid, uint16_t vring, int enable)
        /* 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);
        rte_spinlock_unlock(&state->lock);