selftests: xsk: make stat tests not spin on getsockopt

Convert the stats tests from spinning on the getsockopt to just check
getsockopt once when the Rx thread has received all the packets. The
actual completion of receiving the last packet forms a natural point
in time when the receiver is ready to call the getsockopt to check the
stats. In the previous version , we just span on the getsockopt until
we received the right answer. This could be forever or just getting
the "correct" answer by shear luck.

The pacing_on variable can now be dropped since all test can now
handle pacing properly.
Signed-off-by: Magnus Karlsson <magnus.karlsson@intel.com>
Link: https://lore.kernel.org/r/20220510115604.8717-10-magnus.karlsson@gmail.comSigned-off-by: Alexei Starovoitov <ast@kernel.org>

tools/testing/selftests/bpf/xdpxceiver.h

@@ -27,7 +27,6 @@
 
 #define TEST_PASS 0
 #define TEST_FAILURE -1
-#define TEST_CONTINUE -2
 #define MAX_INTERFACES 2
 #define MAX_INTERFACE_NAME_CHARS 7
 #define MAX_INTERFACES_NAMESPACE_CHARS 10
@@ -147,7 +146,8 @@ struct ifobject {
 	bool rx_on;
 	bool use_poll;
 	bool busy_poll;
-	bool pacing_on;
+	bool use_fill_ring;
+	bool release_rx;
 	u8 dst_mac[ETH_ALEN];
 	u8 src_mac[ETH_ALEN];
 };
@@ -167,6 +167,6 @@ pthread_barrier_t barr;
 pthread_mutex_t pacing_mutex = PTHREAD_MUTEX_INITIALIZER;
 pthread_cond_t pacing_cond = PTHREAD_COND_INITIALIZER;
 
-u32 pkts_in_flight;
+int pkts_in_flight;
 
 #endif				/* XDPXCEIVER_H */