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From: Martin KaFai Lau <martin.lau@linux.dev>
To: ' ' <bpf@vger.kernel.org>, ' ' <netdev@vger.kernel.org>
Cc: 'Alexei Starovoitov ' <ast@kernel.org>,
	'Andrii Nakryiko ' <andrii@kernel.org>,
	'Daniel Borkmann ' <daniel@iogearbox.net>,
	'David Miller ' <davem@davemloft.net>,
	'Jakub Kicinski ' <kuba@kernel.org>,
	'Eric Dumazet ' <edumazet@google.com>,
	'Paolo Abeni ' <pabeni@redhat.com>, ' ' <kernel-team@fb.com>
Subject: [PATCH v3 bpf-next 5/5] selftests/bpf: Check -EBUSY for the recurred bpf_setsockopt(TCP_CONGESTION)
Date: Thu, 29 Sep 2022 00:04:07 -0700	[thread overview]
Message-ID: <20220929070407.965581-6-martin.lau@linux.dev> (raw)
In-Reply-To: <20220929070407.965581-1-martin.lau@linux.dev>

From: Martin KaFai Lau <martin.lau@kernel.org>

This patch changes the bpf_dctcp test to ensure the recurred
bpf_setsockopt(TCP_CONGESTION) returns -EBUSY.

Signed-off-by: Martin KaFai Lau <martin.lau@kernel.org>
---
 .../selftests/bpf/prog_tests/bpf_tcp_ca.c     |  4 +++
 tools/testing/selftests/bpf/progs/bpf_dctcp.c | 25 +++++++++++++------
 2 files changed, 21 insertions(+), 8 deletions(-)

diff --git a/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c b/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
index 2959a52ced06..e980188d4124 100644
--- a/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
+++ b/tools/testing/selftests/bpf/prog_tests/bpf_tcp_ca.c
@@ -290,6 +290,10 @@ static void test_dctcp_fallback(void)
 		goto done;
 	ASSERT_STREQ(dctcp_skel->bss->cc_res, "cubic", "cc_res");
 	ASSERT_EQ(dctcp_skel->bss->tcp_cdg_res, -ENOTSUPP, "tcp_cdg_res");
+	/* All setsockopt(TCP_CONGESTION) in the recurred
+	 * bpf_dctcp->init() should fail with -EBUSY.
+	 */
+	ASSERT_EQ(dctcp_skel->bss->ebusy_cnt, 3, "ebusy_cnt");
 
 	err = getsockopt(srv_fd, SOL_TCP, TCP_CONGESTION, srv_cc, &cc_len);
 	if (!ASSERT_OK(err, "getsockopt(srv_fd, TCP_CONGESTION)"))
diff --git a/tools/testing/selftests/bpf/progs/bpf_dctcp.c b/tools/testing/selftests/bpf/progs/bpf_dctcp.c
index 9573be6122be..460682759aed 100644
--- a/tools/testing/selftests/bpf/progs/bpf_dctcp.c
+++ b/tools/testing/selftests/bpf/progs/bpf_dctcp.c
@@ -11,6 +11,7 @@
 #include <linux/types.h>
 #include <linux/stddef.h>
 #include <linux/tcp.h>
+#include <errno.h>
 #include <bpf/bpf_helpers.h>
 #include <bpf/bpf_tracing.h>
 #include "bpf_tcp_helpers.h"
@@ -23,6 +24,7 @@ const char tcp_cdg[] = "cdg";
 char cc_res[TCP_CA_NAME_MAX];
 int tcp_cdg_res = 0;
 int stg_result = 0;
+int ebusy_cnt = 0;
 
 struct {
 	__uint(type, BPF_MAP_TYPE_SK_STORAGE);
@@ -64,16 +66,23 @@ void BPF_PROG(dctcp_init, struct sock *sk)
 
 	if (!(tp->ecn_flags & TCP_ECN_OK) && fallback[0]) {
 		/* Switch to fallback */
-		bpf_setsockopt(sk, SOL_TCP, TCP_CONGESTION,
-			       (void *)fallback, sizeof(fallback));
-		/* Switch back to myself which the bpf trampoline
-		 * stopped calling dctcp_init recursively.
+		if (bpf_setsockopt(sk, SOL_TCP, TCP_CONGESTION,
+				   (void *)fallback, sizeof(fallback)) == -EBUSY)
+			ebusy_cnt++;
+
+		/* Switch back to myself and the recurred dctcp_init()
+		 * will get -EBUSY for all bpf_setsockopt(TCP_CONGESTION),
+		 * except the last "cdg" one.
 		 */
-		bpf_setsockopt(sk, SOL_TCP, TCP_CONGESTION,
-			       (void *)bpf_dctcp, sizeof(bpf_dctcp));
+		if (bpf_setsockopt(sk, SOL_TCP, TCP_CONGESTION,
+				   (void *)bpf_dctcp, sizeof(bpf_dctcp)) == -EBUSY)
+			ebusy_cnt++;
+
 		/* Switch back to fallback */
-		bpf_setsockopt(sk, SOL_TCP, TCP_CONGESTION,
-			       (void *)fallback, sizeof(fallback));
+		if (bpf_setsockopt(sk, SOL_TCP, TCP_CONGESTION,
+				   (void *)fallback, sizeof(fallback)) == -EBUSY)
+			ebusy_cnt++;
+
 		/* Expecting -ENOTSUPP for tcp_cdg_res */
 		tcp_cdg_res = bpf_setsockopt(sk, SOL_TCP, TCP_CONGESTION,
 					     (void *)tcp_cdg, sizeof(tcp_cdg));
-- 
2.30.2


  parent reply	other threads:[~2022-09-29  7:05 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-29  7:04 [PATCH v3 bpf-next 0/5] bpf: Remove recursion check for struct_ops prog Martin KaFai Lau
2022-09-29  7:04 ` [PATCH v3 bpf-next 1/5] bpf: Add __bpf_prog_{enter,exit}_struct_ops for struct_ops trampoline Martin KaFai Lau
2022-09-29  7:04 ` [PATCH v3 bpf-next 2/5] bpf: Move the "cdg" tcp-cc check to the common sol_tcp_sockopt() Martin KaFai Lau
2022-09-29  7:04 ` [PATCH v3 bpf-next 3/5] bpf: Refactor bpf_setsockopt(TCP_CONGESTION) handling into another function Martin KaFai Lau
2022-09-29  7:04 ` [PATCH v3 bpf-next 4/5] bpf: tcp: Stop bpf_setsockopt(TCP_CONGESTION) in init ops to recur itself Martin KaFai Lau
2022-09-29 16:07   ` Eric Dumazet
2022-09-29  7:04 ` Martin KaFai Lau [this message]
2022-09-29 16:40 ` [PATCH v3 bpf-next 0/5] bpf: Remove recursion check for struct_ops prog patchwork-bot+netdevbpf

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