On 12/29/2016 03:51 AM, Yuanhan Liu wrote:
On Wed, Dec 28, 2016 at 04:10:51PM -0500, Charles (Chas) Williams wrote:
From: Wen Chiu <wc...@brocade.com>
Only increment and decrement nb_started_ports on the first and last
device start and stop. Otherwise, nb_started_ports can become negative
if a device is stopped multiple times.
How could you be able to stop dev (precisely, invoke eth_dev_stop)
multiple times, judging that eth_dev_stop() will be invoked once
only?
void
rte_eth_dev_stop(uint8_t port_id)
{
struct rte_eth_dev *dev;
RTE_ETH_VALID_PORTID_OR_RET(port_id);
dev = &rte_eth_devices[port_id];
RTE_FUNC_PTR_OR_RET(*dev->dev_ops->dev_stop);
==> if (dev->data->dev_started == 0) {
RTE_PMD_DEBUG_TRACE("Device with port_id=%" PRIu8
" already stopped\n",
port_id);
return;
}
==> dev->data->dev_started = 0;
(*dev->dev_ops->dev_stop)(dev);
}
Multiple threads?
No, we aren't using multiple threads for control. But eth_dev_stop()
is called in rte_pmd_vhost_remove():
static int
rte_pmd_vhost_remove(const char *name)
{
...
pthread_mutex_lock(&internal_list_lock);
TAILQ_REMOVE(&internal_list, list, next);
pthread_mutex_unlock(&internal_list_lock);
rte_free(list);
eth_dev_stop(eth_dev);
...
So, if we .dev_stop() and deatch the virtual device, eth_dev_stop()
gets called twice. Calling .dev_stop() when you are about to detach
the device seems completely reasonable. It also seems reasonable to
call eth_dev_stop() inside rte_pmd_vhost_remove() in case the end
user didn't do a .dev_stop().
