On 18.10.2016 15:28, Jan Blunck wrote:

If the application already configured queues the PMD should not
silently claim ownership and reset them.

What exactly is the problem when changing MTU? This works fine from
what I can tell.

Following scenario leads to APP PANIC:

	1. mempool_1 = rte_mempool_create()
	2. rte_eth_rx_queue_setup(bond0, ..., mempool_1);
	3. rte_eth_dev_start(bond0);
	4. mempool_2 = rte_mempool_create();
	5. rte_eth_dev_stop(bond0);
	6. rte_eth_rx_queue_setup(bond0, ..., mempool_2);
	7. rte_eth_dev_start(bond0);
	* RX queues still use 'mempool_1' because reconfiguration doesn't affect them. *
	8. rte_mempool_free(mempool_1);
	9. On any rx operation we'll get PANIC because of using freed 'mempool_1':
	 PANIC in rte_mempool_get_ops():
	 assert "(ops_index >= 0) && (ops_index < RTE_MEMPOOL_MAX_OPS_IDX)" failed

You may just start OVS 2.6 with DPDK bonding device and attempt to change MTU via 'mtu_request'.
Bug is easily reproducible.

Best regards, Ilya Maximets.

On Wed, Sep 7, 2016 at 2:28 PM, Ilya Maximets [off-list ref] wrote:

quoted

This reverts commit 5b7bb2bda5519b7800f814df64d4e015282140e5.

It is necessary to reconfigure all queues every time because configuration
can be changed.

For example, if we're reconfiguring bonding device with new memory pool,
already configured queues will still use the old one. And if the old
mempool be freed, application likely will panic in attempt to use
freed mempool.

This happens when we use the bonding device with OVS 2.6 while MTU
reconfiguration:

PANIC in rte_mempool_get_ops():
assert "(ops_index >= 0) && (ops_index < RTE_MEMPOOL_MAX_OPS_IDX)" failed

Cc: <redacted>
Signed-off-by: Ilya Maximets <redacted>
---
 drivers/net/bonding/rte_eth_bond_pmd.c | 10 ++--------
 1 file changed, 2 insertions(+), 8 deletions(-)

diff --git a/drivers/net/bonding/rte_eth_bond_pmd.c b/drivers/net/bonding/rte_eth_bond_pmd.c
index b20a272..eb5b6d1 100644
--- a/drivers/net/bonding/rte_eth_bond_pmd.c
+++ b/drivers/net/bonding/rte_eth_bond_pmd.c

@@ -1305,8 +1305,6 @@ slave_configure(struct rte_eth_dev *bonded_eth_dev,
        struct bond_rx_queue *bd_rx_q;
        struct bond_tx_queue *bd_tx_q;

-       uint16_t old_nb_tx_queues = slave_eth_dev->data->nb_tx_queues;
-       uint16_t old_nb_rx_queues = slave_eth_dev->data->nb_rx_queues;
        int errval;
        uint16_t q_id;

@@ -1347,9 +1345,7 @@ slave_configure(struct rte_eth_dev *bonded_eth_dev,
        }

        /* Setup Rx Queues */
-       /* Use existing queues, if any */
-       for (q_id = old_nb_rx_queues;
-            q_id < bonded_eth_dev->data->nb_rx_queues; q_id++) {
+       for (q_id = 0; q_id < bonded_eth_dev->data->nb_rx_queues; q_id++) {
                bd_rx_q = (struct bond_rx_queue *)bonded_eth_dev->data->rx_queues[q_id];

                errval = rte_eth_rx_queue_setup(slave_eth_dev->data->port_id, q_id,

@@ -1365,9 +1361,7 @@ slave_configure(struct rte_eth_dev *bonded_eth_dev,
        }

        /* Setup Tx Queues */
-       /* Use existing queues, if any */
-       for (q_id = old_nb_tx_queues;
-            q_id < bonded_eth_dev->data->nb_tx_queues; q_id++) {
+       for (q_id = 0; q_id < bonded_eth_dev->data->nb_tx_queues; q_id++) {
                bd_tx_q = (struct bond_tx_queue *)bonded_eth_dev->data->tx_queues[q_id];

                errval = rte_eth_tx_queue_setup(slave_eth_dev->data->port_id, q_id,
--

2.7.4