[RFC -next 10/10] selftests: Add sendfile zerocopy notification test

Joe Damato
2025-03-19T00:15:53Z

Extend the existing the msg_zerocopy test to allow testing sendfile to
ensure that notifications are generated.

Signed-off-by: Joe Damato <jdamato@fastly.com>
---
tools/testing/selftests/net/msg_zerocopy.c | 54 ++++++++++++++++++++-
tools/testing/selftests/net/msg_zerocopy.sh | 5 ++
2 files changed, 58 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/net/msg_zerocopy.c b/tools/testing/selftests/net/msg_zerocopy.c
index 7ea5fb28c93d..20e334b25fbd 100644
--- a/tools/testing/selftests/net/msg_zerocopy.c
+++ b/tools/testing/selftests/net/msg_zerocopy.c
@@ -30,6 +30,7 @@
#include <arpa/inet.h>
#include <error.h>
#include <errno.h>
+#include <fcntl.h>
#include <limits.h>
#include <linux/errqueue.h>
#include <linux/if_packet.h>
@@ -50,6 +51,7 @@
#include <stdlib.h>
#include <string.h>
#include <sys/ioctl.h>
+#include <sys/sendfile.h>
#include <sys/socket.h>
#include <sys/stat.h>
#include <sys/time.h>
@@ -74,6 +76,14 @@
#define MSG_ZEROCOPY 0x4000000
#endif

+#ifndef SENDFILE_ZC
+#define SENDFILE_ZC (0x2)
+#endif
+
+#ifndef __NR_sendfile2
+#define __NR_sendfile2 467
+#endif
+
static int cfg_cork;
static bool cfg_cork_mixed;
static int cfg_cpu = -1; /* default: pin to last cpu */
@@ -87,6 +97,8 @@ static int cfg_verbose;
static int cfg_waittime_ms = 500;
static int cfg_notification_limit = 32;
static bool cfg_zerocopy;
+static bool cfg_sendfile;
+static const char *cfg_sendfile_path;

static socklen_t cfg_alen;
static struct sockaddr_storage cfg_dst_addr;
@@ -182,6 +194,37 @@ static void add_zcopy_cookie(struct msghdr *msg, uint32_t cookie)
memcpy(CMSG_DATA(cm), &cookie, sizeof(cookie));
}

+static bool do_sendfile(int fd)
+{
+ int from_fd = open(cfg_sendfile_path, O_RDONLY, 0);
+ struct stat buf;
+ ssize_t total = 0;
+ ssize_t ret = 0;
+ off_t off = 0;
+
+ if (fd < 0)
+ error(1, errno, "couldn't open sendfile path");
+
+ if (fstat(from_fd, &buf))
+ error(1, errno, "couldn't fstat");
+
+ while (total < buf.st_size) {
+ ret = syscall(__NR_sendfile2, fd, from_fd, &off, buf.st_size,
+ SENDFILE_ZC);
+ if (ret < 0)
+ error(1, errno, "unable to sendfile");
+ total += ret;
+ sends_since_notify++;
+ bytes += ret;
+ packets++;
+ if (ret > 0)
+ expected_completions++;
+ }
+
+ close(from_fd);
+ return total == buf.st_size;
+}
+
static bool do_sendmsg(int fd, struct msghdr *msg, bool do_zerocopy, int domain)
{
int ret, len, i, flags;
@@ -550,6 +593,8 @@ static void do_tx(int domain, int type, int protocol)
do {
if (cfg_cork)
do_sendmsg_corked(fd, &msg);
+ else if (cfg_sendfile)
+ do_sendfile(fd);
else
do_sendmsg(fd, &msg, cfg_zerocopy, domain);

@@ -715,7 +760,7 @@ static void parse_opts(int argc, char **argv)

cfg_payload_len = max_payload_len;

- while ((c = getopt(argc, argv, "46c:C:D:i:l:mp:rs:S:t:vz")) != -1) {
+ while ((c = getopt(argc, argv, "46c:C:D:i:l:mp:rs:S:t:vzf:w:")) != -1) {
switch (c) {
case '4':
if (cfg_family != PF_UNSPEC)
@@ -767,9 +812,16 @@ static void parse_opts(int argc, char **argv)
case 'v':
cfg_verbose++;
break;
+ case 'f':
+ cfg_sendfile = true;
+ cfg_sendfile_path = optarg;
+ break;
case 'z':
cfg_zerocopy = true;
break;
+ case 'w':
+ cfg_waittime_ms = 200 + strtoul(optarg, NULL, 10) * 1000;
+ break;
}
}

diff --git a/tools/testing/selftests/net/msg_zerocopy.sh b/tools/testing/selftests/net/msg_zerocopy.sh
index 89c22f5320e0..c735e4ab86b5 100755
--- a/tools/testing/selftests/net/msg_zerocopy.sh
+++ b/tools/testing/selftests/net/msg_zerocopy.sh
@@ -74,6 +74,7 @@ esac
cleanup() {
ip netns del "${NS2}"
ip netns del "${NS1}"
+ rm -f sendfile_data
}

trap cleanup EXIT
@@ -106,6 +107,9 @@ ip -netns "${NS2}" addr add fd::2/64 dev "${DEV}" nodad
# Optionally disable sg or csum offload to test edge cases
# ip netns exec "${NS1}" ethtool -K "${DEV}" sg off

+# create sendfile test data
+dd if=/dev/zero of=sendfile_data bs=1M count=8 2> /dev/null
+
do_test() {
local readonly ARGS="$1"

@@ -118,4 +122,5 @@ do_test() {

do_test "${EXTRA_ARGS}"
do_test "-z ${EXTRA_ARGS}"
+do_test "-z -f sendfile_data ${EXTRA_ARGS}"
echo ok
--
2.43.0