From: Yucong Sun <fallentree@fb.com>
Date: Wed, 25 Aug 2021 11:47:45 -0700
Subject: selftests/bpf: Reduce more flakyness in sockmap_listen
Patch-mainline: v5.15-rc1
Git-commit: 3599bc5101b36d9ff88da17fe65b001aeadd9c62
References: jsc#PED-1377

This patch adds similar retry logic to more places where read() is used, to
reduce flakyness in slow CI environment.

Signed-off-by: Yucong Sun <fallentree@fb.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210825184745.2680830-1-fallentree@fb.com
Acked-by: Shung-Hsi Yu <shung-hsi.yu@suse.com>
---
 tools/testing/selftests/bpf/prog_tests/sockmap_listen.c |   19 +++++++++++++---
 1 file changed, 16 insertions(+), 3 deletions(-)

--- a/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c
+++ b/tools/testing/selftests/bpf/prog_tests/sockmap_listen.c
@@ -949,6 +949,7 @@ static void redir_to_connected(int famil
 	int err, n;
 	u32 key;
 	char b;
+	int retries = 100;
 
 	zero_verdict_count(verd_mapfd);
 
@@ -1001,10 +1002,15 @@ static void redir_to_connected(int famil
 		goto close_peer1;
 	if (pass != 1)
 		FAIL("%s: want pass count 1, have %d", log_prefix, pass);
-
+again:
 	n = read(c0, &b, 1);
-	if (n < 0)
+	if (n < 0) {
+		if (errno == EAGAIN && retries--) {
+			usleep(1000);
+			goto again;
+		}
 		FAIL_ERRNO("%s: read", log_prefix);
+	}
 	if (n == 0)
 		FAIL("%s: incomplete read", log_prefix);
 
@@ -1926,6 +1932,7 @@ static void unix_inet_redir_to_connected
 	int sfd[2];
 	u32 key;
 	char b;
+	int retries = 100;
 
 	zero_verdict_count(verd_mapfd);
 
@@ -1956,9 +1963,15 @@ static void unix_inet_redir_to_connected
 	if (pass != 1)
 		FAIL("%s: want pass count 1, have %d", log_prefix, pass);
 
+again:
 	n = read(mode == REDIR_INGRESS ? p0 : c0, &b, 1);
-	if (n < 0)
+	if (n < 0) {
+		if (errno == EAGAIN && retries--) {
+			usleep(1000);
+			goto again;
+		}
 		FAIL_ERRNO("%s: read", log_prefix);
+	}
 	if (n == 0)
 		FAIL("%s: incomplete read", log_prefix);