[dpdk-stable] [PATCH] examples/kni: fix crash during MTU set

[Ferruh Yigit <ferruh.yigit@intel.com>]

During MTU set (kni_change_mtu) sample application setup queues, which
can free and re-allocate queues.
Meanwhile sample application keeps continues in Rx/Tx burst calls in
different threads, which may cause crash during queue setup.

Pausing application Rx/Tx calls before MTU set and starts it back
afterwards.

Bugzilla ID: 482
Fixes: a26b116749a3 ("examples/kni: fix MTU change to setup Tx queue")
Cc: stable@dpdk.org

Signed-off-by: Ferruh Yigit <ferruh.yigit@intel.com>
---
Cc: Rasesh Mody <rmody@marvell.com>
Cc: Xi Zhang <xix.zhang@intel.com>
---
 examples/kni/main.c | 16 ++++++++++++++--
 1 file changed, 14 insertions(+), 2 deletions(-)

diff --git a/examples/kni/main.c b/examples/kni/main.c
index 7a927a50c0..80dd0353e7 100644
--- a/examples/kni/main.c
+++ b/examples/kni/main.c
@@ -768,9 +768,8 @@ monitor_all_ports_link_status(void *arg)
 	return NULL;
 }
 
-/* Callback for request of changing MTU */
 static int
-kni_change_mtu(uint16_t port_id, unsigned int new_mtu)
+kni_change_mtu_(uint16_t port_id, unsigned int new_mtu)
 {
 	int ret;
 	uint16_t nb_rxd = NB_RXD;
@@ -851,6 +850,19 @@ kni_change_mtu(uint16_t port_id, unsigned int new_mtu)
 	return 0;
 }
 
+/* Callback for request of changing MTU */
+static int
+kni_change_mtu(uint16_t port_id, unsigned int new_mtu)
+{
+	int ret;
+
+	rte_atomic32_inc(&kni_pause);
+	ret =  kni_change_mtu_(port_id, new_mtu);
+	rte_atomic32_dec(&kni_pause);
+
+	return ret;
+}
+
 /* Callback for request of configuring network interface up/down */
 static int
 kni_config_network_interface(uint16_t port_id, uint8_t if_up)
-- 
2.25.4