[PATCH net-next v2 2/2] selftests: drv-net: ncdevmem: gracefully retry bind()

[Mina Almasry <almasrymina@google.com>]

During tests, ethnl_rings_set randomly bounces the link causing a
transient IPv6 Duplicate Address Detection "tentative" race, resulting
in spurious -EADDRNOTAVAIL aborts inside the ncdevmem server.

Add a simple 10 second retry loop around bind() to absorb the link bounce.

Signed-off-by: Mina Almasry <almasrymina@google.com>
---
v2:
- Refactored C99 mid-scope variables to strictly adhere to C89 styling.
- Dropped single-line curly brace avoidance syntax.
v1: https://patchwork.kernel.org/project/netdevbpf/patch/20260801131220.1367229-2-almasrymina@google.com/
---
 tools/testing/selftests/drivers/net/hw/ncdevmem.c | 8 +++++++-
 1 file changed, 7 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/drivers/net/hw/ncdevmem.c b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
index ffe1d5c1fa4e1..67901a0123e8c 100644
--- a/tools/testing/selftests/drivers/net/hw/ncdevmem.c
+++ b/tools/testing/selftests/drivers/net/hw/ncdevmem.c
@@ -843,6 +843,7 @@ static int do_server(struct memory_buffer *mem)
 	char iobuf[819200];
 	int ret, err = -1;
 	char buffer[256];
+	int retries = 10;
 	int socket_fd;
 	int client_fd;
 
@@ -898,7 +899,12 @@ static int do_server(struct memory_buffer *mem)
 	fprintf(stderr, "binding to address %s:%d\n", server_ip,
 		ntohs(server_sin.sin6_port));
 
-	ret = bind(socket_fd, &server_sin, sizeof(server_sin));
+	while (retries--) {
+		ret = bind(socket_fd, &server_sin, sizeof(server_sin));
+		if (!ret)
+			break;
+		sleep(1);
+	}
 	if (ret) {
 		pr_err("Failed to bind");
 		goto err_close_socket;
-- 
2.55.0.571.g244d577d93-goog