[PATCH 3/3] io_uring: Support IOSQE_CQE_SKIP_SUCCESS in io_uring zerocopy test

[Oliver Crumrine <ozlinuxc@gmail.com>]

Add support for the IOSQE_CQE_SKIP_SUCCESS flag in the io_uring_zerocopy_tx
test, using the "-a" option. Instead of incrementing when
IORING_CQE_F_MORE is set, remember how many SQEs are sent and simply
wait on notifs instead of regular completions. For non-zc stuff, there
won't be notifs or completions, so don't wait on either of those, but
check the completion queue for errors at the end to make sure none have
popped up.

The changes to the shell script run the tests both with and without the
"-a" option.

Signed-off-by: Oliver Crumrine <ozlinuxc@gmail.com>
---
 .../selftests/net/io_uring_zerocopy_tx.c      | 38 +++++++++++++++++--
 .../selftests/net/io_uring_zerocopy_tx.sh     |  7 +++-
 2 files changed, 39 insertions(+), 6 deletions(-)

diff --git a/tools/testing/selftests/net/io_uring_zerocopy_tx.c b/tools/testing/selftests/net/io_uring_zerocopy_tx.c
index 76e604e4810e..11a43594935f 100644
--- a/tools/testing/selftests/net/io_uring_zerocopy_tx.c
+++ b/tools/testing/selftests/net/io_uring_zerocopy_tx.c
@@ -50,8 +50,10 @@ enum {
 };
 
 static bool cfg_cork		= false;
+static bool cfg_nocqe		= false;
 static int  cfg_mode		= MODE_ZC_FIXED;
 static int  cfg_nr_reqs		= 8;
+static int  cfg_nr_completions	= 8;
 static int  cfg_family		= PF_UNSPEC;
 static int  cfg_payload_len;
 static int  cfg_port		= 8000;
@@ -134,11 +136,21 @@ static void do_tx(int domain, int type, int protocol)
 			if (mode == MODE_NONZC) {
 				io_uring_prep_send(sqe, fd, payload,
 						   cfg_payload_len, msg_flags);
+				if (cfg_nocqe) {
+					sqe->flags |= IOSQE_CQE_SKIP_SUCCESS;
+					cfg_nr_completions--;
+				}
 				sqe->user_data = NONZC_TAG;
 			} else {
 				io_uring_prep_sendzc(sqe, fd, payload,
 						     cfg_payload_len,
 						     msg_flags, zc_flags);
+				if (cfg_nocqe) {
+					sqe->flags |= IOSQE_CQE_SKIP_SUCCESS;
+					packets++;
+					compl_cqes++;
+					bytes += cfg_payload_len;
+				}
 				if (mode == MODE_ZC_FIXED) {
 					sqe->ioprio |= IORING_RECVSEND_FIXED_BUF;
 					sqe->buf_index = buf_idx;
@@ -153,7 +165,7 @@ static void do_tx(int domain, int type, int protocol)
 
 		if (cfg_cork)
 			do_setsockopt(fd, IPPROTO_UDP, UDP_CORK, 0);
-		for (i = 0; i < cfg_nr_reqs; i++) {
+		for (i = 0; i < cfg_nr_completions; i++) {
 			ret = io_uring_wait_cqe(&ring, &cqe);
 			if (ret)
 				error(1, ret, "wait cqe");
@@ -168,7 +180,9 @@ static void do_tx(int domain, int type, int protocol)
 				if (compl_cqes <= 0)
 					error(1, -EINVAL, "notification mismatch");
 				compl_cqes--;
-				i--;
+				if (!cfg_nocqe)
+					i--;
 				io_uring_cqe_seen(&ring);
 				continue;
 			}
@@ -200,6 +214,17 @@ static void do_tx(int domain, int type, int protocol)
 		compl_cqes--;
 	}
 
+	/* The above code does not account for a send error when
+	 * IOSQE_CQE_SKIP_SUCCESS is set. This is operating under the
+	 * assumption that an error CQE will get put on the ring before
+	 * the above code completes:
+	 */
+	while (!io_uring_peek_cqe(&ring, &cqe)) {
+		if (cqe->res == -EAGAIN)
+			continue;
+		error(1, -EINVAL, "send failed");
+	}
+
 	fprintf(stderr, "tx=%lu (MB=%lu), tx/s=%lu (MB/s=%lu)\n",
 			packets, bytes >> 20,
 			packets / (cfg_runtime_ms / 1000),
@@ -221,7 +246,7 @@ static void do_test(int domain, int type, int protocol)
 static void usage(const char *filepath)
 {
 	error(1, 0, "Usage: %s (-4|-6) (udp|tcp) -D<dst_ip> [-s<payload size>] "
-		    "[-t<time s>] [-n<batch>] [-p<port>] [-m<mode>]", filepath);
+		    "[-t<time s>] [-n<batch>] [-p<port>] [-m<mode>] [-a]", filepath);
 }
 
 static void parse_opts(int argc, char **argv)
@@ -239,7 +264,7 @@ static void parse_opts(int argc, char **argv)
 		usage(argv[0]);
 	cfg_payload_len = max_payload_len;
 
-	while ((c = getopt(argc, argv, "46D:p:s:t:n:c:m:")) != -1) {
+	while ((c = getopt(argc, argv, "46aD:p:s:t:n:c:m:")) != -1) {
 		switch (c) {
 		case '4':
 			if (cfg_family != PF_UNSPEC)
@@ -274,6 +299,9 @@ static void parse_opts(int argc, char **argv)
 		case 'm':
 			cfg_mode = strtol(optarg, NULL, 0);
 			break;
+		case 'a':
+			cfg_nocqe = true;
+			break;
 		}
 	}
 
@@ -302,6 +330,8 @@ static void parse_opts(int argc, char **argv)
 		error(1, 0, "-s: payload exceeds max (%d)", max_payload_len);
 	if (optind != argc - 1)
 		usage(argv[0]);
+
+	cfg_nr_completions = cfg_nr_reqs;
 }
 
 int main(int argc, char **argv)
diff --git a/tools/testing/selftests/net/io_uring_zerocopy_tx.sh b/tools/testing/selftests/net/io_uring_zerocopy_tx.sh
index 123439545013..aeb4645b7891 100755
--- a/tools/testing/selftests/net/io_uring_zerocopy_tx.sh
+++ b/tools/testing/selftests/net/io_uring_zerocopy_tx.sh
@@ -25,11 +25,14 @@ readonly path_sysctl_mem="net.core.optmem_max"
 # No arguments: automated test
 if [[ "$#" -eq "0" ]]; then
 	IPs=( "4" "6" )
+	SKIPCQEs=("" "-a")
 
 	for IP in "${IPs[@]}"; do
 		for mode in $(seq 1 3); do
-			$0 "$IP" udp -m "$mode" -t 1 -n 32
-			$0 "$IP" tcp -m "$mode" -t 1 -n 1
+			for cqe in "${SKIPCQEs[@]}"; do
+				$0 "$IP" udp -m "$mode" -t 1 -n 32 "$cqe"
+				$0 "$IP" tcp -m "$mode" -t 1 -n 1  "$cqe"
+			done
 		done
 	done
 
-- 
2.44.0