[PATCH] net/bonding: set initial value of descriptor count alignment

[Ivan Malov <ivan.malov@oktetlabs.ru>]

The driver had once been broken by patch [1] looking to have
a non-zero "nb_max" value in a use case not involving adding
any back-end ports. That was addressed afterwards ([2]). But,
as per report [3], similar test cases exist which attempt to
setup Rx queues on a void bond before attaching any back-end
ports. Rx queue setup, in turn, involves device info get API
invocation, and one of the checks on received data causes an
exception (division by zero). The "nb_align" value is indeed
zero at that time, but, as explained in [2], such test cases
are totally incorrect since a bond device must have at least
one back-end port plugged before any ethdev APIs can be used.

Once again, to avoid any problems with fixing the test cases,
this patch adjusts the bond PMD itself to workaround the bug.

[1] commit 5be3b40fea60 ("net/bonding: fix values of descriptor limits")
[2] commit d03c0e83cc00 ("net/bonding: fix descriptor limit reporting")
[3] https://bugs.dpdk.org/show_bug.cgi?id=1118

Fixes: d03c0e83cc00 ("net/bonding: fix descriptor limit reporting")
Cc: stable@dpdk.org

Signed-off-by: Ivan Malov <ivan.malov@oktetlabs.ru>
Reviewed-by: Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
---
 drivers/net/bonding/rte_eth_bond_pmd.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/net/bonding/rte_eth_bond_pmd.c b/drivers/net/bonding/rte_eth_bond_pmd.c
index dc74852137..145cb7099f 100644
--- a/drivers/net/bonding/rte_eth_bond_pmd.c
+++ b/drivers/net/bonding/rte_eth_bond_pmd.c
@@ -3426,6 +3426,8 @@ bond_alloc(struct rte_vdev_device *dev, uint8_t mode)
 	 */
 	internals->rx_desc_lim.nb_max = UINT16_MAX;
 	internals->tx_desc_lim.nb_max = UINT16_MAX;
+	internals->rx_desc_lim.nb_align = 1;
+	internals->tx_desc_lim.nb_align = 1;
 
 	memset(internals->active_slaves, 0, sizeof(internals->active_slaves));
 	memset(internals->slaves, 0, sizeof(internals->slaves));
-- 
2.30.2