Re: [RESEND PATCH net-next v4 3/4] test/vsock: Add retry mechanism to ioctl wrapper

[Xuewei Niu]

> On Thu, Jul 03, 2025 at 11:05:14AM +0800, Xuewei Niu wrote:
> >Resend: the previous message was rejected due to HTML
> >Resend: forgot to reply all...
> >
> >> On Mon, Jun 30, 2025 at 03:57:26PM +0800, Xuewei Niu wrote:
> >> >Wrap the ioctl in `ioctl_int()`, which takes a pointer to the actual
> >> >int value and an expected int value. The function will not return until
> >> >either the ioctl returns the expected value or a timeout occurs, thus
> >> >avoiding immediate failure.
> >> >
> >> >Signed-off-by: Xuewei Niu <niuxuewei.nxw@xxxxxxxxxxxx>
> >> >---
> >> > tools/testing/vsock/util.c | 32 +++++++++++++++++++++++---------
> >> > tools/testing/vsock/util.h |  1 +
> >> > 2 files changed, 24 insertions(+), 9 deletions(-)
> >> >
> >> >diff --git a/tools/testing/vsock/util.c b/tools/testing/vsock/util.c
> >> >index 0c7e9cbcbc85..481c395227e4 100644
> >> >--- a/tools/testing/vsock/util.c
> >> >+++ b/tools/testing/vsock/util.c
> >> >@@ -16,6 +16,7 @@
> >> > #include <unistd.h>
> >> > #include <assert.h>
> >> > #include <sys/epoll.h>
> >> >+#include <sys/ioctl.h>
> >> > #include <sys/mman.h>
> >> > #include <linux/sockios.h>
> >> >
> >> >@@ -97,28 +98,41 @@ void vsock_wait_remote_close(int fd)
> >> > 	close(epollfd);
> >> > }
> >> >
> >> >-/* Wait until transport reports no data left to be sent.
> >> >- * Return false if transport does not implement the unsent_bytes()
> >> >callback.
> >> >+/* Wait until ioctl gives an expected int value.
> >> >+ * Return false if the op is not supported.
> >> >  */
> >> >-bool vsock_wait_sent(int fd)
> >> >+bool vsock_ioctl_int(int fd, unsigned long op, int *actual, int expected)
> >>
> >> Why we need the `actual` parameter?
> >
> >We can exit early `if (*actual == expected)`, and the `expected` can be any integer.
> >I also make it to be a pointer, because the caller might need to have the actual value.
> 
> IIUC this function return true if `*actual == expected` or false if 
> there was an error, so I don't see the point of aving `actual`, since it 
> can only be equal to `expected` if it returns true, or invalid if it 
> returs false.

Nice catch! I'll remove it in v5.

Thanks,
Xuewei

> Thanks,
> Stefano
> 
> >
> >Thanks,
> >Xuewei
> >
> >> > {
> >> >-	int ret, sock_bytes_unsent;
> >> >+	int ret;
> >> >+	char name[32];
> >> >+
> >> >+	snprintf(name, sizeof(name), "ioctl(%lu)", op);
> >> >
> >> > 	timeout_begin(TIMEOUT);
> >> > 	do {
> >> >-		ret = ioctl(fd, SIOCOUTQ, &sock_bytes_unsent);
> >> >+		ret = ioctl(fd, op, actual);
> >> > 		if (ret < 0) {
> >> > 			if (errno == EOPNOTSUPP)
> >> > 				break;
> >> >
> >> >-			perror("ioctl(SIOCOUTQ)");
> >> >+			perror(name);
> >> > 			exit(EXIT_FAILURE);
> >> > 		}
> >> >-		timeout_check("SIOCOUTQ");
> >> >-	} while (sock_bytes_unsent != 0);
> >> >+		timeout_check(name);
> >> >+	} while (*actual != expected);
> >> > 	timeout_end();
> >> >
> >> >-	return !ret;
> >> >+	return ret >= 0;
> >> >+}
> >> >+
> >> >+/* Wait until transport reports no data left to be sent.
> >> >+ * Return false if transport does not implement the unsent_bytes() callback.
> >> >+ */
> >> >+bool vsock_wait_sent(int fd)
> >> >+{
> >> >+	int sock_bytes_unsent;
> >> >+
> >> >+	return vsock_ioctl_int(fd, SIOCOUTQ, &sock_bytes_unsent, 0);
> >> > }
> >> >
> >> > /* Create socket <type>, bind to <cid, port> and return the file descriptor. */
> >> >diff --git a/tools/testing/vsock/util.h b/tools/testing/vsock/util.h
> >> >index 5e2db67072d5..d59581f68d61 100644
> >> >--- a/tools/testing/vsock/util.h
> >> >+++ b/tools/testing/vsock/util.h
> >> >@@ -54,6 +54,7 @@ int vsock_stream_listen(unsigned int cid, unsigned int port);
> >> > int vsock_seqpacket_accept(unsigned int cid, unsigned int port,
> >> > 			   struct sockaddr_vm *clientaddrp);
> >> > void vsock_wait_remote_close(int fd);
> >> >+bool vsock_ioctl_int(int fd, unsigned long op, int *actual, int expected);
> >> > bool vsock_wait_sent(int fd);
> >> > void send_buf(int fd, const void *buf, size_t len, int flags,
> >> > 	      ssize_t expected_ret);
> >> >--
> >> >2.34.1
> >> >
> >