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.c

@@ -424,7 +424,8 @@ static void __test_spec_init(struct test_spec *test, struct ifobject *ifobj_tx,
 
 		ifobj->xsk = &ifobj->xsk_arr[0];
 		ifobj->use_poll = false;
-		ifobj->pacing_on = true;
+		ifobj->use_fill_ring = true;
+		ifobj->release_rx = true;
 		ifobj->pkt_stream = test->pkt_stream_default;
 		ifobj->validation_func = NULL;
 
@@ -503,9 +504,10 @@ static struct pkt *pkt_stream_get_pkt(struct pkt_stream *pkt_stream, u32 pkt_nb)
 	return &pkt_stream->pkts[pkt_nb];
 }
 
-static struct pkt *pkt_stream_get_next_rx_pkt(struct pkt_stream *pkt_stream)
+static struct pkt *pkt_stream_get_next_rx_pkt(struct pkt_stream *pkt_stream, u32 *pkts_sent)
 {
 	while (pkt_stream->rx_pkt_nb < pkt_stream->nb_pkts) {
+		(*pkts_sent)++;
 		if (pkt_stream->pkts[pkt_stream->rx_pkt_nb].valid)
 			return &pkt_stream->pkts[pkt_stream->rx_pkt_nb++];
 		pkt_stream->rx_pkt_nb++;
@@ -521,10 +523,16 @@ static void pkt_stream_delete(struct pkt_stream *pkt_stream)
 
 static void pkt_stream_restore_default(struct test_spec *test)
 {
-	if (test->ifobj_tx->pkt_stream != test->pkt_stream_default) {
+	struct pkt_stream *tx_pkt_stream = test->ifobj_tx->pkt_stream;
+
+	if (tx_pkt_stream != test->pkt_stream_default) {
 		pkt_stream_delete(test->ifobj_tx->pkt_stream);
 		test->ifobj_tx->pkt_stream = test->pkt_stream_default;
 	}
+
+	if (test->ifobj_rx->pkt_stream != test->pkt_stream_default &&
+	    test->ifobj_rx->pkt_stream != tx_pkt_stream)
+		pkt_stream_delete(test->ifobj_rx->pkt_stream);
 	test->ifobj_rx->pkt_stream = test->pkt_stream_default;
 }
 
@@ -546,6 +554,16 @@ static struct pkt_stream *__pkt_stream_alloc(u32 nb_pkts)
 	return pkt_stream;
 }
 
+static void pkt_set(struct xsk_umem_info *umem, struct pkt *pkt, u64 addr, u32 len)
+{
+	pkt->addr = addr;
+	pkt->len = len;
+	if (len > umem->frame_size - XDP_PACKET_HEADROOM - MIN_PKT_SIZE * 2 - umem->frame_headroom)
+		pkt->valid = false;
+	else
+		pkt->valid = true;
+}
+
 static struct pkt_stream *pkt_stream_generate(struct xsk_umem_info *umem, u32 nb_pkts, u32 pkt_len)
 {
 	struct pkt_stream *pkt_stream;
@@ -557,14 +575,9 @@ static struct pkt_stream *pkt_stream_generate(struct xsk_umem_info *umem, u32 nb
 
 	pkt_stream->nb_pkts = nb_pkts;
 	for (i = 0; i < nb_pkts; i++) {
-		pkt_stream->pkts[i].addr = (i % umem->num_frames) * umem->frame_size;
-		pkt_stream->pkts[i].len = pkt_len;
+		pkt_set(umem, &pkt_stream->pkts[i], (i % umem->num_frames) * umem->frame_size,
+			pkt_len);
 		pkt_stream->pkts[i].payload = i;
-
-		if (pkt_len > umem->frame_size)
-			pkt_stream->pkts[i].valid = false;
-		else
-			pkt_stream->pkts[i].valid = true;
 	}
 
 	return pkt_stream;
@@ -592,15 +605,27 @@ static void pkt_stream_replace_half(struct test_spec *test, u32 pkt_len, int off
 	u32 i;
 
 	pkt_stream = pkt_stream_clone(umem, test->pkt_stream_default);
-	for (i = 1; i < test->pkt_stream_default->nb_pkts; i += 2) {
-		pkt_stream->pkts[i].addr = (i % umem->num_frames) * umem->frame_size + offset;
-		pkt_stream->pkts[i].len = pkt_len;
-	}
+	for (i = 1; i < test->pkt_stream_default->nb_pkts; i += 2)
+		pkt_set(umem, &pkt_stream->pkts[i],
+			(i % umem->num_frames) * umem->frame_size + offset, pkt_len);
 
 	test->ifobj_tx->pkt_stream = pkt_stream;
 	test->ifobj_rx->pkt_stream = pkt_stream;
 }
 
+static void pkt_stream_receive_half(struct test_spec *test)
+{
+	struct xsk_umem_info *umem = test->ifobj_rx->umem;
+	struct pkt_stream *pkt_stream = test->ifobj_tx->pkt_stream;
+	u32 i;
+
+	test->ifobj_rx->pkt_stream = pkt_stream_generate(umem, pkt_stream->nb_pkts,
+							 pkt_stream->pkts[0].len);
+	pkt_stream = test->ifobj_rx->pkt_stream;
+	for (i = 1; i < pkt_stream->nb_pkts; i += 2)
+		pkt_stream->pkts[i].valid = false;
+}
+
 static struct pkt *pkt_generate(struct ifobject *ifobject, u32 pkt_nb)
 {
 	struct pkt *pkt = pkt_stream_get_pkt(ifobject->pkt_stream, pkt_nb);
@@ -795,11 +820,11 @@ static int complete_pkts(struct xsk_socket_info *xsk, int batch_size)
 static int receive_pkts(struct ifobject *ifobj, struct pollfd *fds)
 {
 	struct timeval tv_end, tv_now, tv_timeout = {RECV_TMOUT, 0};
+	u32 idx_rx = 0, idx_fq = 0, rcvd, i, pkts_sent = 0;
 	struct pkt_stream *pkt_stream = ifobj->pkt_stream;
-	struct pkt *pkt = pkt_stream_get_next_rx_pkt(pkt_stream);
 	struct xsk_socket_info *xsk = ifobj->xsk;
 	struct xsk_umem_info *umem = xsk->umem;
-	u32 idx_rx = 0, idx_fq = 0, rcvd, i;
+	struct pkt *pkt;
 	int ret;
 
 	ret = gettimeofday(&tv_now, NULL);
@@ -807,6 +832,7 @@ static int receive_pkts(struct ifobject *ifobj, struct pollfd *fds)
 		exit_with_error(errno);
 	timeradd(&tv_now, &tv_timeout, &tv_end);
 
+	pkt = pkt_stream_get_next_rx_pkt(pkt_stream, &pkts_sent);
 	while (pkt) {
 		ret = gettimeofday(&tv_now, NULL);
 		if (ret)
@@ -828,6 +854,7 @@ static int receive_pkts(struct ifobject *ifobj, struct pollfd *fds)
 			continue;
 		}
 
+		if (ifobj->use_fill_ring) {
 			ret = xsk_ring_prod__reserve(&umem->fq, rcvd, &idx_fq);
 			while (ret != rcvd) {
 				if (ret < 0)
@@ -839,19 +866,12 @@ static int receive_pkts(struct ifobject *ifobj, struct pollfd *fds)
 				}
 				ret = xsk_ring_prod__reserve(&umem->fq, rcvd, &idx_fq);
 			}
+		}
 
 		for (i = 0; i < rcvd; i++) {
 			const struct xdp_desc *desc = xsk_ring_cons__rx_desc(&xsk->rx, idx_rx++);
 			u64 addr = desc->addr, orig;
 
-			if (!pkt) {
-				ksft_print_msg("[%s] Received too many packets.\n",
-					       __func__);
-				ksft_print_msg("Last packet has addr: %llx len: %u\n",
-					       addr, desc->len);
-				return TEST_FAILURE;
-			}
-
 			orig = xsk_umem__extract_addr(addr);
 			addr = xsk_umem__add_offset_to_addr(addr);
 
@@ -859,18 +879,22 @@ static int receive_pkts(struct ifobject *ifobj, struct pollfd *fds)
 			    !is_offset_correct(umem, pkt_stream, addr, pkt->addr))
 				return TEST_FAILURE;
 
+			if (ifobj->use_fill_ring)
 				*xsk_ring_prod__fill_addr(&umem->fq, idx_fq++) = orig;
-			pkt = pkt_stream_get_next_rx_pkt(pkt_stream);
+			pkt = pkt_stream_get_next_rx_pkt(pkt_stream, &pkts_sent);
 		}
 
+		if (ifobj->use_fill_ring)
 			xsk_ring_prod__submit(&umem->fq, rcvd);
+		if (ifobj->release_rx)
 			xsk_ring_cons__release(&xsk->rx, rcvd);
 
 		pthread_mutex_lock(&pacing_mutex);
-		pkts_in_flight -= rcvd;
+		pkts_in_flight -= pkts_sent;
 		if (pkts_in_flight < umem->num_frames)
 			pthread_cond_signal(&pacing_cond);
 		pthread_mutex_unlock(&pacing_mutex);
+		pkts_sent = 0;
 	}
 
 	return TEST_PASS;
@@ -900,7 +924,8 @@ static int __send_pkts(struct ifobject *ifobject, u32 *pkt_nb)
 
 	pthread_mutex_lock(&pacing_mutex);
 	pkts_in_flight += valid_pkts;
-	if (ifobject->pacing_on && pkts_in_flight >= ifobject->umem->num_frames - BATCH_SIZE) {
+	/* pkts_in_flight might be negative if many invalid packets are sent */
+	if (pkts_in_flight >= (int)(ifobject->umem->num_frames - BATCH_SIZE)) {
 		kick_tx(xsk);
 		pthread_cond_wait(&pacing_cond, &pacing_mutex);
 	}
@@ -987,34 +1012,29 @@ static int validate_rx_dropped(struct ifobject *ifobject)
 	if (err)
 		return TEST_FAILURE;
 
-	if (stats.rx_dropped == ifobject->pkt_stream->nb_pkts)
+	if (stats.rx_dropped == ifobject->pkt_stream->nb_pkts / 2)
 		return TEST_PASS;
 
-	return TEST_CONTINUE;
+	return TEST_FAILURE;
 }
 
 static int validate_rx_full(struct ifobject *ifobject)
 {
 	struct xsk_socket *xsk = ifobject->xsk->xsk;
 	struct xdp_statistics stats;
-	u32 expected_stat;
 	int err;
 
+	usleep(1000);
 	kick_rx(ifobject->xsk);
 
 	err = get_xsk_stats(xsk, &stats);
 	if (err)
 		return TEST_FAILURE;
 
-	if (ifobject->umem->num_frames < XSK_RING_PROD__DEFAULT_NUM_DESCS)
-		expected_stat = ifobject->umem->num_frames - RX_FULL_RXQSIZE;
-	else
-		expected_stat = XSK_RING_PROD__DEFAULT_NUM_DESCS - RX_FULL_RXQSIZE;
-
-	if (stats.rx_ring_full == expected_stat)
+	if (stats.rx_ring_full)
 		return TEST_PASS;
 
-	return TEST_CONTINUE;
+	return TEST_FAILURE;
 }
 
 static int validate_fill_empty(struct ifobject *ifobject)
@@ -1023,16 +1043,17 @@ static int validate_fill_empty(struct ifobject *ifobject)
 	struct xdp_statistics stats;
 	int err;
 
+	usleep(1000);
 	kick_rx(ifobject->xsk);
 
 	err = get_xsk_stats(xsk, &stats);
 	if (err)
 		return TEST_FAILURE;
 
-	if (stats.rx_fill_ring_empty_descs == ifobject->pkt_stream->nb_pkts)
+	if (stats.rx_fill_ring_empty_descs)
 		return TEST_PASS;
 
-	return TEST_CONTINUE;
+	return TEST_FAILURE;
 }
 
 static int validate_tx_invalid_descs(struct ifobject *ifobject)
@@ -1051,7 +1072,7 @@ static int validate_tx_invalid_descs(struct ifobject *ifobject)
 		return TEST_FAILURE;
 	}
 
-	if (stats.tx_invalid_descs != ifobject->pkt_stream->nb_pkts) {
+	if (stats.tx_invalid_descs != ifobject->pkt_stream->nb_pkts / 2) {
 		ksft_print_msg("[%s] tx_invalid_descs incorrect. Got [%u] expected [%u]\n",
 			       __func__, stats.tx_invalid_descs, ifobject->pkt_stream->nb_pkts);
 		return TEST_FAILURE;
@@ -1138,17 +1159,12 @@ static void *worker_testapp_validate_tx(void *arg)
 	print_verbose("Sending %d packets on interface %s\n", ifobject->pkt_stream->nb_pkts,
 		      ifobject->ifname);
 	err = send_pkts(test, ifobject);
-	if (err) {
-		report_failure(test);
-		goto out;
-	}
 
-	if (ifobject->validation_func) {
+	if (!err && ifobject->validation_func)
 		err = ifobject->validation_func(ifobject);
+	if (err)
 		report_failure(test);
-	}
 
-out:
 	if (test->total_steps == test->current_step || err)
 		testapp_cleanup_xsk_res(ifobject);
 	pthread_exit(NULL);
@@ -1202,14 +1218,10 @@ static void *worker_testapp_validate_rx(void *arg)
 
 	pthread_barrier_wait(&barr);
 
-	if (ifobject->validation_func) {
-		do {
-			err = ifobject->validation_func(ifobject);
-		} while (err == TEST_CONTINUE);
-	} else {
 	err = receive_pkts(ifobject, &fds);
-	}
 
+	if (!err && ifobject->validation_func)
+		err = ifobject->validation_func(ifobject);
 	if (err) {
 		report_failure(test);
 		pthread_mutex_lock(&pacing_mutex);
@@ -1327,9 +1339,10 @@ static void testapp_headroom(struct test_spec *test)
 static void testapp_stats_rx_dropped(struct test_spec *test)
 {
 	test_spec_set_name(test, "STAT_RX_DROPPED");
-	test->ifobj_tx->pacing_on = false;
 	test->ifobj_rx->umem->frame_headroom = test->ifobj_rx->umem->frame_size -
-		XDP_PACKET_HEADROOM - 1;
+		XDP_PACKET_HEADROOM - MIN_PKT_SIZE * 3;
+	pkt_stream_replace_half(test, MIN_PKT_SIZE * 4, 0);
+	pkt_stream_receive_half(test);
 	test->ifobj_rx->validation_func = validate_rx_dropped;
 	testapp_validate_traffic(test);
 }
@@ -1337,8 +1350,7 @@ static void testapp_stats_rx_dropped(struct test_spec *test)
 static void testapp_stats_tx_invalid_descs(struct test_spec *test)
 {
 	test_spec_set_name(test, "STAT_TX_INVALID");
-	test->ifobj_tx->pacing_on = false;
-	pkt_stream_replace(test, DEFAULT_PKT_CNT, XSK_UMEM__INVALID_FRAME_SIZE);
+	pkt_stream_replace_half(test, XSK_UMEM__INVALID_FRAME_SIZE, 0);
 	test->ifobj_tx->validation_func = validate_tx_invalid_descs;
 	testapp_validate_traffic(test);
 
@@ -1348,20 +1360,30 @@ static void testapp_stats_tx_invalid_descs(struct test_spec *test)
 static void testapp_stats_rx_full(struct test_spec *test)
 {
 	test_spec_set_name(test, "STAT_RX_FULL");
-	test->ifobj_tx->pacing_on = false;
-	test->ifobj_rx->xsk->rxqsize = RX_FULL_RXQSIZE;
+	pkt_stream_replace(test, DEFAULT_UMEM_BUFFERS + DEFAULT_UMEM_BUFFERS / 2, PKT_SIZE);
+	test->ifobj_rx->pkt_stream = pkt_stream_generate(test->ifobj_rx->umem,
+							 DEFAULT_UMEM_BUFFERS, PKT_SIZE);
+	if (!test->ifobj_rx->pkt_stream)
+		exit_with_error(ENOMEM);
+
+	test->ifobj_rx->xsk->rxqsize = DEFAULT_UMEM_BUFFERS;
+	test->ifobj_rx->release_rx = false;
 	test->ifobj_rx->validation_func = validate_rx_full;
 	testapp_validate_traffic(test);
+
+	pkt_stream_restore_default(test);
 }
 
 static void testapp_stats_fill_empty(struct test_spec *test)
 {
 	test_spec_set_name(test, "STAT_RX_FILL_EMPTY");
-	test->ifobj_tx->pacing_on = false;
-	test->ifobj_rx->pkt_stream = pkt_stream_generate(test->ifobj_rx->umem, 0, MIN_PKT_SIZE);
+	pkt_stream_replace(test, DEFAULT_UMEM_BUFFERS + DEFAULT_UMEM_BUFFERS / 2, PKT_SIZE);
+	test->ifobj_rx->pkt_stream = pkt_stream_generate(test->ifobj_rx->umem,
+							 DEFAULT_UMEM_BUFFERS, PKT_SIZE);
 	if (!test->ifobj_rx->pkt_stream)
 		exit_with_error(ENOMEM);
-	test->ifobj_rx->pkt_stream->use_addr_for_fill = true;
+
+	test->ifobj_rx->use_fill_ring = false;
 	test->ifobj_rx->validation_func = validate_fill_empty;
 	testapp_validate_traffic(test);
 
@@ -1504,7 +1526,7 @@ static void run_pkt_test(struct test_spec *test, enum test_mode mode, enum test_
 		test_spec_set_name(test, "RUN_TO_COMPLETION_2K_FRAME_SIZE");
 		test->ifobj_tx->umem->frame_size = 2048;
 		test->ifobj_rx->umem->frame_size = 2048;
-		pkt_stream_replace(test, DEFAULT_PKT_CNT, MIN_PKT_SIZE);
+		pkt_stream_replace(test, DEFAULT_PKT_CNT, PKT_SIZE);
 		testapp_validate_traffic(test);
 
 		pkt_stream_restore_default(test);

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 */