These tests:
"SOCK_STREAM ioctl(SIOCOUTQ) 0 unsent bytes"
"SOCK_SEQPACKET ioctl(SIOCOUTQ) 0 unsent bytes"
output: "Unexpected 'SIOCOUTQ' value, expected 0, got 64 (CLIENT)".
They test that the SIOCOUTQ ioctl reports 0 unsent bytes after the data
have been received by the other side. However, sometimes there is a delay
in updating this "unsent bytes" counter, and the test fails even though
the counter properly goes to 0 several milliseconds later.
The delay occurs in the kernel because the used buffer notification
callback virtio_vsock_tx_done(), called upon receipt of the data by the
other side, doesn't update the counter itself. It delegates that to
a kernel thread (via vsock->tx_work). Sometimes that thread is delayed
more than the test expects.
Change the test to poll SIOCOUTQ until it returns 0 or a timeout occurs.
Signed-off-by: Konstantin Shkolnyy <[email protected]>
---
Changes in v2:
- Use timeout_check() to end polling, instead of counting iterations.
tools/testing/vsock/vsock_test.c | 28 ++++++++++++++++------------
1 file changed, 16 insertions(+), 12 deletions(-)
diff --git a/tools/testing/vsock/vsock_test.c b/tools/testing/vsock/vsock_test.c
index d0f6d253ac72..613551132a96 100644
--- a/tools/testing/vsock/vsock_test.c
+++ b/tools/testing/vsock/vsock_test.c
@@ -1264,21 +1264,25 @@ static void test_unsent_bytes_client(const struct
test_opts *opts, int type)
send_buf(fd, buf, sizeof(buf), 0, sizeof(buf));
control_expectln("RECEIVED");
- ret = ioctl(fd, SIOCOUTQ, &sock_bytes_unsent);
- if (ret < 0) {
- if (errno == EOPNOTSUPP) {
- fprintf(stderr, "Test skipped, SIOCOUTQ not
supported.\n");
- } else {
+ /* SIOCOUTQ isn't guaranteed to instantly track sent data. Even though
+ * the "RECEIVED" message means that the other side has received the
+ * data, there can be a delay in our kernel before updating the "unsent
+ * bytes" counter. Repeat SIOCOUTQ until it returns 0.
+ */
+ timeout_begin(TIMEOUT);
+ do {
+ ret = ioctl(fd, SIOCOUTQ, &sock_bytes_unsent);
+ if (ret < 0) {
+ if (errno == EOPNOTSUPP) {
+ fprintf(stderr, "Test skipped, SIOCOUTQ not
supported.\n");
+ break;
+ }
perror("ioctl");
exit(EXIT_FAILURE);
}
- } else if (ret == 0 && sock_bytes_unsent != 0) {
- fprintf(stderr,
- "Unexpected 'SIOCOUTQ' value, expected 0, got %i\n",
- sock_bytes_unsent);
- exit(EXIT_FAILURE);
- }
-
+ timeout_check("SIOCOUTQ");
+ } while (sock_bytes_unsent != 0);
+ timeout_end();
close(fd);
}
--
2.34.1
