This will be used as a 'probe' mode in the selftest to check whether
the device supports the devmem or not. Use hard-coded queue layout
(two last queues) and prevent user from passing custom -q and/or -t.

Reviewed-by: Mina Almasry <almasrymina@google.com>
Signed-off-by: Stanislav Fomichev <sdf@fomichev.me>
---
 tools/testing/selftests/net/ncdevmem.c | 42 ++++++++++++++++++++------
 1 file changed, 32 insertions(+), 10 deletions(-)

diff --git a/tools/testing/selftests/net/ncdevmem.c b/tools/testing/selftests/net/ncdevmem.c
index fe4d81ef1ca5..07a91516103a 100644
--- a/tools/testing/selftests/net/ncdevmem.c
+++ b/tools/testing/selftests/net/ncdevmem.c
@@ -76,7 +76,7 @@ static char *client_ip;
 static char *port;
 static size_t do_validation;
 static int start_queue = -1;
-static int num_queues = 1;
+static int num_queues = -1;
 static char *ifname;
 static unsigned int ifindex;
 static unsigned int dmabuf_id;
@@ -718,19 +718,31 @@ int main(int argc, char *argv[])
 		}
 	}
 
-	if (!server_ip)
-		error(1, 0, "Missing -s argument\n");
-
-	if (!port)
-		error(1, 0, "Missing -p argument\n");
-
 	if (!ifname)
 		error(1, 0, "Missing -f argument\n");
 
 	ifindex = if_nametoindex(ifname);
 
-	if (start_queue < 0) {
-		start_queue = rxq_num(ifindex) - 1;
+	if (!server_ip && !client_ip) {
+		if (start_queue < 0 && num_queues < 0) {
+			num_queues = rxq_num(ifindex);
+			if (num_queues < 0)
+				error(1, 0, "couldn't detect number of queues\n");
+			/* make sure can bind to multiple queues */
+			start_queue = num_queues / 2;
+			num_queues /= 2;
+		}
+
+		if (start_queue < 0 || num_queues < 0)
+			error(1, 0, "Both -t and -q are required\n");
+
+		run_devmem_tests();
+		return 0;
+	}
+
+	if (start_queue < 0 && num_queues < 0) {
+		num_queues = 1;
+		start_queue = rxq_num(ifindex) - num_queues;
 
 		if (start_queue < 0)
 			error(1, 0, "couldn't detect number of queues\n");
@@ -741,7 +753,17 @@ int main(int argc, char *argv[])
 	for (; optind < argc; optind++)
 		fprintf(stderr, "extra arguments: %s\n", argv[optind]);
 
-	run_devmem_tests();
+	if (start_queue < 0)
+		error(1, 0, "Missing -t argument\n");
+
+	if (num_queues < 0)
+		error(1, 0, "Missing -q argument\n");
+
+	if (!server_ip)
+		error(1, 0, "Missing -s argument\n");
+
+	if (!port)
+		error(1, 0, "Missing -p argument\n");
 
 	mem = provider->alloc(getpagesize() * NUM_PAGES);
 	ret = is_server ? do_server(mem) : 1;
-- 
2.47.0