selftests: make order checking verbose in msg_zerocopy selftest

[ Upstream commit 7d6d8f0c8b700c9493f2839abccb6d29028b4219 ]

We find that when lock debugging is on, notifications may not come in
order. Thus, we have order checking outputs managed by cfg_verbose, to
avoid too many outputs in this case.

Fixes: 07b65c5 ("test: add msg_zerocopy test")
Signed-off-by: Zijian Zhang <[email protected]>
Signed-off-by: Xiaochun Lu <[email protected]>
Reviewed-by: Willem de Bruijn <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>
Signed-off-by: Sasha Levin <[email protected]>
(cherry picked from commit b1cb48187a6edc2ab72f5b3e6b4af7a232730d64)
Signed-off-by: Harshit Mogalapalli <[email protected]>
Signed-off-by: Vegard Nossum <[email protected]>

tools/testing/selftests/net/msg_zerocopy.c

@@ -351,7 +351,7 @@ static bool do_recv_completion(int fd)
 	/* Detect notification gaps. These should not happen often, if at all.
 	 * Gaps can occur due to drops, reordering and retransmissions.
 	 */
-	if (lo != next_completion)
+	if (cfg_verbose && lo != next_completion)
 		fprintf(stderr, "gap: %u..%u does not append to %u\n",
 			lo, hi, next_completion);
 	next_completion = hi + 1;