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From:   Benjamin Tissoires <benjamin.tissoires@redhat.com>
To:     Greg KH <gregkh@linuxfoundation.org>,
        Jiri Kosina <jikos@kernel.org>,
        Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Dmitry Torokhov <dmitry.torokhov@gmail.com>
Cc:     Tero Kristo <tero.kristo@linux.intel.com>,
        linux-kernel@vger.kernel.org, linux-input@vger.kernel.org,
        netdev@vger.kernel.org, bpf@vger.kernel.org,
        linux-kselftest@vger.kernel.org,
        Benjamin Tissoires <benjamin.tissoires@redhat.com>
Subject: [PATCH HID for-next v2 3/9] selftests: hid: attach/detach 2 bpf programs, not just one
Date:   Fri, 13 Jan 2023 10:09:29 +0100
Message-Id: <20230113090935.1763477-4-benjamin.tissoires@redhat.com>
In-Reply-To: <20230113090935.1763477-1-benjamin.tissoires@redhat.com>
References: <20230113090935.1763477-1-benjamin.tissoires@redhat.com>
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Add a second BPF program to attach to the device, as the development of
this feature showed that we also need to ensure we can detach multiple
programs to a device (hid_bpf_link->hid_table_index was actually not set
initially, and this lead to any BPF program not being released except for
the first one).

Signed-off-by: Benjamin Tissoires <benjamin.tissoires@redhat.com>

---

changes in v2:
- rewrote commit message s/->index/->hid_table_index/
---
 tools/testing/selftests/hid/hid_bpf.c   |  8 +++++++-
 tools/testing/selftests/hid/progs/hid.c | 13 +++++++++++++
 2 files changed, 20 insertions(+), 1 deletion(-)

diff --git a/tools/testing/selftests/hid/hid_bpf.c b/tools/testing/selftests/hid/hid_bpf.c
index 6615c26fb5dd..d215bb492eb4 100644
--- a/tools/testing/selftests/hid/hid_bpf.c
+++ b/tools/testing/selftests/hid/hid_bpf.c
@@ -616,6 +616,7 @@ TEST_F(hid_bpf, test_attach_detach)
 {
 	const struct test_program progs[] = {
 		{ .name = "hid_first_event" },
+		{ .name = "hid_second_event" },
 	};
 	__u8 buf[10] = {0};
 	int err;
@@ -634,7 +635,10 @@ TEST_F(hid_bpf, test_attach_detach)
 	ASSERT_EQ(buf[0], 1);
 	ASSERT_EQ(buf[2], 47);
 
-	/* pin the program and immediately unpin it */
+	/* make sure both programs are run */
+	ASSERT_EQ(buf[3], 52);
+
+	/* pin the first program and immediately unpin it */
 #define PIN_PATH "/sys/fs/bpf/hid_first_event"
 	bpf_program__pin(self->skel->progs.hid_first_event, PIN_PATH);
 	remove(PIN_PATH);
@@ -660,6 +664,7 @@ TEST_F(hid_bpf, test_attach_detach)
 	ASSERT_EQ(buf[0], 1);
 	ASSERT_EQ(buf[1], 47);
 	ASSERT_EQ(buf[2], 0);
+	ASSERT_EQ(buf[3], 0);
 
 	/* re-attach our program */
 
@@ -677,6 +682,7 @@ TEST_F(hid_bpf, test_attach_detach)
 	ASSERT_EQ(err, 6) TH_LOG("read_hidraw");
 	ASSERT_EQ(buf[0], 1);
 	ASSERT_EQ(buf[2], 47);
+	ASSERT_EQ(buf[3], 52);
 }
 
 /*
diff --git a/tools/testing/selftests/hid/progs/hid.c b/tools/testing/selftests/hid/progs/hid.c
index 6a86af0aa545..88c593f753b5 100644
--- a/tools/testing/selftests/hid/progs/hid.c
+++ b/tools/testing/selftests/hid/progs/hid.c
@@ -32,6 +32,19 @@ int BPF_PROG(hid_first_event, struct hid_bpf_ctx *hid_ctx)
 	return hid_ctx->size;
 }
 
+SEC("?fmod_ret/hid_bpf_device_event")
+int BPF_PROG(hid_second_event, struct hid_bpf_ctx *hid_ctx)
+{
+	__u8 *rw_data = hid_bpf_get_data(hid_ctx, 0 /* offset */, 4 /* size */);
+
+	if (!rw_data)
+		return 0; /* EPERM check */
+
+	rw_data[3] = rw_data[2] + 5;
+
+	return hid_ctx->size;
+}
+
 SEC("?fmod_ret/hid_bpf_device_event")
 int BPF_PROG(hid_change_report_id, struct hid_bpf_ctx *hid_ctx)
 {
-- 
2.38.1