Re: [PATCH] Revert "bonding: use existing enslaved device queues"

[Eric Kinzie <ehkinzie@gmail.com>]

On Wed Oct 12 16:24:21 +0100 2016, Bruce Richardson wrote:
> On Wed, Oct 12, 2016 at 04:24:54PM +0300, Ilya Maximets wrote:
> > On 07.10.2016 05:02, Eric Kinzie wrote:
> > > On Wed Sep 07 15:28:10 +0300 2016, Ilya Maximets wrote:
> > >> 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: <stable@dpdk.org>
> > >> Signed-off-by: Ilya Maximets <i.maximets@samsung.com>
> > >> ---
> > >>  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
> > >>
> > > 
> > > NAK
> > > 
> > > There are still some users of this code.  Let's give them a chance to
> > > comment before removing it.
> > 
> > Hi Eric,
> > 
> > Are these users in CC-list? If not, could you, please, add them?
> > This patch awaits in mail-list already more than a month. I think, it's enough
> > time period for all who wants to say something. Patch fixes a real bug that
> > prevent using of DPDK bonding in all applications that reconfigures devices
> > in runtime including OVS.
> > 
> Agreed.
> 
> Eric, does reverting this patch cause you problems directly, or is your concern
> just with regards to potential impact to others?
> 
> Thanks,
> /Bruce

This won't impact me directly.  The users are CCed (different thread)
and I haven't seen any comment, so I no longer have any objection to
reverting this change.

Eric