net/failsafe: fix Rx clean race

When removing a device, the fail-safe checks that it is not within its
datapath before cleaning it.

When checking whether an Rx burst should be performed on a device, the
remove flag is not checked. Thus the port could still enter its datapath
and miss a removal round. Furthermore, there is a race between the
thread removing the device and the polling thread.

Check the remove flag before entering a sub-device Rx burst when in safe
mode. This check mitigates the aforementioned race condition.

Fixes: 72a57bfd9a0e ("net/failsafe: add fast burst functions")
Cc: stable@dpdk.org

Signed-off-by: Matan Azrad <matan@mellanox.com>
Acked-by: Gaetan Rivet <gaetan.rivet@6wind.com>

drivers/net/failsafe/failsafe_rxtx.c

@@ -43,7 +43,8 @@ fs_rx_unsafe(struct sub_device *sdev)
 {
 	return (ETH(sdev) == NULL) ||
 		(ETH(sdev)->rx_pkt_burst == NULL) ||
-		(sdev->state != DEV_STARTED);
+		(sdev->state != DEV_STARTED) ||
+		(sdev->remove != 0);
 }
 
 static inline int