io_uring/zcrx: add selftest case for recvzc with read limit

Add a selftest case to iou-zcrx where the sender sends 4x4K = 16K and
the receiver does 4x4K recvzc requests. Validate that the requests
complete successfully and that the data is not corrupted.

Signed-off-by: David Wei <dw@davidwei.uk>
Link: https://lore.kernel.org/r/20250224041319.2389785-3-dw@davidwei.uk
Signed-off-by: Jens Axboe <axboe@kernel.dk>

Author: spikeh

tools/testing/selftests/drivers/net/hw/iou-zcrx.c

@@ -61,6 +61,9 @@ static int cfg_port = 8000;
 static int cfg_payload_len;
 static const char *cfg_ifname;
 static int cfg_queue_id = -1;
+static bool cfg_oneshot;
+static int cfg_oneshot_recvs;
+static int cfg_send_size = SEND_SIZE;
 static struct sockaddr_in6 cfg_addr;
 
 static char payload[SEND_SIZE] __attribute__((aligned(PAGE_SIZE)));
@@ -196,6 +199,17 @@ static void add_recvzc(struct io_uring *ring, int sockfd)
 	sqe->user_data = 2;
 }
 
+static void add_recvzc_oneshot(struct io_uring *ring, int sockfd, size_t len)
+{
+	struct io_uring_sqe *sqe;
+
+	sqe = io_uring_get_sqe(ring);
+
+	io_uring_prep_rw(IORING_OP_RECV_ZC, sqe, sockfd, NULL, len, 0);
+	sqe->ioprio |= IORING_RECV_MULTISHOT;
+	sqe->user_data = 2;
+}
+
 static void process_accept(struct io_uring *ring, struct io_uring_cqe *cqe)
 {
 	if (cqe->res < 0)
@@ -204,7 +218,10 @@ static void process_accept(struct io_uring *ring, struct io_uring_cqe *cqe)
 		error(1, 0, "Unexpected second connection");
 
 	connfd = cqe->res;
-	add_recvzc(ring, connfd);
+	if (cfg_oneshot)
+		add_recvzc_oneshot(ring, connfd, PAGE_SIZE);
+	else
+		add_recvzc(ring, connfd);
 }
 
 static void process_recvzc(struct io_uring *ring, struct io_uring_cqe *cqe)
@@ -218,16 +235,22 @@ static void process_recvzc(struct io_uring *ring, struct io_uring_cqe *cqe)
 	ssize_t n;
 	int i;
 
-	if (cqe->res == 0 && cqe->flags == 0) {
+	if (cqe->res == 0 && cqe->flags == 0 && cfg_oneshot_recvs == 0) {
 		stop = true;
 		return;
 	}
 
 	if (cqe->res < 0)
 		error(1, 0, "recvzc(): %d", cqe->res);
 
-	if (!(cqe->flags & IORING_CQE_F_MORE))
+	if (cfg_oneshot) {
+		if (cqe->res == 0 && cqe->flags == 0 && cfg_oneshot_recvs) {
+			add_recvzc_oneshot(ring, connfd, PAGE_SIZE);
+			cfg_oneshot_recvs--;
+		}
+	} else if (!(cqe->flags & IORING_CQE_F_MORE)) {
 		add_recvzc(ring, connfd);
+	}
 
 	rcqe = (struct io_uring_zcrx_cqe *)(cqe + 1);
 
@@ -237,7 +260,7 @@ static void process_recvzc(struct io_uring *ring, struct io_uring_cqe *cqe)
 
 	for (i = 0; i < n; i++) {
 		if (*(data + i) != payload[(received + i)])
-			error(1, 0, "payload mismatch");
+			error(1, 0, "payload mismatch at ", i);
 	}
 	received += n;
 
@@ -313,7 +336,7 @@ static void run_server(void)
 
 static void run_client(void)
 {
-	ssize_t to_send = SEND_SIZE;
+	ssize_t to_send = cfg_send_size;
 	ssize_t sent = 0;
 	ssize_t chunk, res;
 	int fd;
@@ -360,7 +383,7 @@ static void parse_opts(int argc, char **argv)
 		usage(argv[0]);
 	cfg_payload_len = max_payload_len;
 
-	while ((c = getopt(argc, argv, "46sch:p:l:i:q:")) != -1) {
+	while ((c = getopt(argc, argv, "sch:p:l:i:q:o:z:")) != -1) {
 		switch (c) {
 		case 's':
 			if (cfg_client)
@@ -387,6 +410,14 @@ static void parse_opts(int argc, char **argv)
 		case 'q':
 			cfg_queue_id = strtoul(optarg, NULL, 0);
 			break;
+		case 'o': {
+			cfg_oneshot = true;
+			cfg_oneshot_recvs = strtoul(optarg, NULL, 0);
+			break;
+		}
+		case 'z':
+			cfg_send_size = strtoul(optarg, NULL, 0);
+			break;
 		}
 	}
 

tools/testing/selftests/drivers/net/hw/iou-zcrx.py

@@ -34,14 +34,37 @@ def test_zcrx(cfg) -> None:
         raise KsftSkipEx('at least 2 combined channels required')
     rx_ring = _get_rx_ring_entries(cfg)
 
-    rx_cmd = f"{cfg.bin_remote} -s -p 9999 -i {cfg.ifname} -q {combined_chans - 1}"
-    tx_cmd = f"{cfg.bin_local} -c -h {cfg.remote_v6} -p 9999 -l 12840"
+    try:
+        ethtool(f"-G {cfg.ifname} rx 64", host=cfg.remote)
+        ethtool(f"-X {cfg.ifname} equal {combined_chans - 1}", host=cfg.remote)
+        flow_rule_id = _set_flow_rule(cfg, combined_chans - 1)
+
+        rx_cmd = f"{cfg.bin_remote} -s -p 9999 -i {cfg.ifname} -q {combined_chans - 1}"
+        tx_cmd = f"{cfg.bin_local} -c -h {cfg.remote_v6} -p 9999 -l 12840"
+        with bkg(rx_cmd, host=cfg.remote, exit_wait=True):
+            wait_port_listen(9999, proto="tcp", host=cfg.remote)
+            cmd(tx_cmd)
+    finally:
+        ethtool(f"-N {cfg.ifname} delete {flow_rule_id}", host=cfg.remote)
+        ethtool(f"-X {cfg.ifname} default", host=cfg.remote)
+        ethtool(f"-G {cfg.ifname} rx {rx_ring}", host=cfg.remote)
+
+
+def test_zcrx_oneshot(cfg) -> None:
+    cfg.require_v6()
+
+    combined_chans = _get_combined_channels(cfg)
+    if combined_chans < 2:
+        raise KsftSkipEx('at least 2 combined channels required')
+    rx_ring = _get_rx_ring_entries(cfg)
 
     try:
         ethtool(f"-G {cfg.ifname} rx 64", host=cfg.remote)
         ethtool(f"-X {cfg.ifname} equal {combined_chans - 1}", host=cfg.remote)
         flow_rule_id = _set_flow_rule(cfg, combined_chans - 1)
 
+        rx_cmd = f"{cfg.bin_remote} -s -p 9999 -i {cfg.ifname} -q {combined_chans - 1} -o 4"
+        tx_cmd = f"{cfg.bin_local} -c -h {cfg.remote_v6} -p 9999 -l 4096 -z 16384"
         with bkg(rx_cmd, host=cfg.remote, exit_wait=True):
             wait_port_listen(9999, proto="tcp", host=cfg.remote)
             cmd(tx_cmd)