diff mbox series

[bpf-next,v2,5/6] selftests/bpf: detach a struct_ops link from the subsystem managing it.

Message ID 20240507055600.2382627-6-thinker.li@gmail.com (mailing list archive)
State Superseded
Delegated to: BPF
Headers show
Series Notify user space when a struct_ops object is detached/unregistered | expand

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Commit Message

Kui-Feng Lee May 7, 2024, 5:55 a.m. UTC 
Not only a user space program can detach a struct_ops link, the subsystem
managing a link can also detach the link. This patch add a kfunc to
simulate detaching a link by the subsystem managing it.

Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
---
 .../selftests/bpf/bpf_testmod/bpf_testmod.c   | 21 ++++++
 .../bpf/prog_tests/test_struct_ops_module.c   | 65 +++++++++++++++++++
 .../selftests/bpf/progs/struct_ops_detach.c   |  6 ++
 3 files changed, 92 insertions(+)

Comments

Martin KaFai Lau May 8, 2024, 11:50 p.m. UTC | #1 
On 5/6/24 10:55 PM, Kui-Feng Lee wrote:
> Not only a user space program can detach a struct_ops link, the subsystem
> managing a link can also detach the link. This patch add a kfunc to
> simulate detaching a link by the subsystem managing it.
> 
> Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
> ---
>   .../selftests/bpf/bpf_testmod/bpf_testmod.c   | 21 ++++++
>   .../bpf/prog_tests/test_struct_ops_module.c   | 65 +++++++++++++++++++
>   .../selftests/bpf/progs/struct_ops_detach.c   |  6 ++
>   3 files changed, 92 insertions(+)
> 
> diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
> index c89a6414c69f..0bf1acc1767a 100644
> --- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
> +++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
> @@ -502,6 +502,26 @@ __bpf_kfunc void bpf_kfunc_call_test_sleepable(void)
>   static DEFINE_MUTEX(detach_mutex);
>   static struct bpf_link *link_to_detach;
>   
> +__bpf_kfunc int bpf_dummy_do_link_detach(void)
> +{
> +	struct bpf_link *link;
> +	int ret = -ENOENT;
> +
> +	mutex_lock(&detach_mutex);
> +	link = link_to_detach;
> +	/* Make sure the link is still valid by increasing its refcnt */
> +	if (link && !atomic64_inc_not_zero(&link->refcnt))

It is better to reuse the bpf_link_inc_not_zero().

> +		link = NULL;
> +	mutex_unlock(&detach_mutex);
> +
> +	if (link) {
> +		ret = link->ops->detach(link);
> +		bpf_link_put(link);
> +	}
> +
> +	return ret;
> +}
> +
>   BTF_KFUNCS_START(bpf_testmod_check_kfunc_ids)
>   BTF_ID_FLAGS(func, bpf_testmod_test_mod_kfunc)
>   BTF_ID_FLAGS(func, bpf_kfunc_call_test1)
> @@ -529,6 +549,7 @@ BTF_ID_FLAGS(func, bpf_kfunc_call_test_destructive, KF_DESTRUCTIVE)
>   BTF_ID_FLAGS(func, bpf_kfunc_call_test_static_unused_arg)
>   BTF_ID_FLAGS(func, bpf_kfunc_call_test_offset)
>   BTF_ID_FLAGS(func, bpf_kfunc_call_test_sleepable, KF_SLEEPABLE)
> +BTF_ID_FLAGS(func, bpf_dummy_do_link_detach)

It should need KF_SLEEPABLE. mutex is used.

>   BTF_KFUNCS_END(bpf_testmod_check_kfunc_ids)
>   
>   static int bpf_testmod_ops_init(struct btf *btf)
> diff --git a/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c
> index f39455b81664..9f6657b53a93 100644
> --- a/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c
> +++ b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c
> @@ -229,6 +229,69 @@ static void test_detach_link(void)
>   	struct_ops_detach__destroy(skel);
>   }
>   
> +/* Detach a link from the subsystem that the link was registered to */
> +static void test_subsystem_detach(void)
> +{
> +	LIBBPF_OPTS(bpf_test_run_opts, topts,
> +		    .data_in = &pkt_v4,
> +		    .data_size_in = sizeof(pkt_v4));
> +	struct epoll_event ev, events[2];
> +	struct struct_ops_detach *skel;
> +	struct bpf_link *link = NULL;
> +	int fd, epollfd = -1, nfds;
> +	int prog_fd;
> +	int err;
> +
> +	skel = struct_ops_detach__open_and_load();
> +	if (!ASSERT_OK_PTR(skel, "struct_ops_detach_open_and_load"))
> +		return;
> +
> +	link = bpf_map__attach_struct_ops(skel->maps.testmod_do_detach);
> +	if (!ASSERT_OK_PTR(link, "attach_struct_ops"))
> +		goto cleanup;
> +
> +	fd = bpf_link__fd(link);
> +	if (!ASSERT_GE(fd, 0, "link_fd"))
> +		goto cleanup;
> +
> +	prog_fd = bpf_program__fd(skel->progs.start_detach);
> +	if (!ASSERT_GE(prog_fd, 0, "start_detach_fd"))
> +		goto cleanup;
> +
> +	/* Do detachment from the registered subsystem */
> +	err = bpf_prog_test_run_opts(prog_fd, &topts);
> +	if (!ASSERT_OK(err, "start_detach_run"))
> +		goto cleanup;
> +
> +	if (!ASSERT_EQ(topts.retval, 0, "start_detach_run retval"))
> +		goto cleanup;
> +
> +	epollfd = epoll_create1(0);
> +	if (!ASSERT_GE(epollfd, 0, "epoll_create1"))
> +		goto cleanup;
> +
> +	ev.events = EPOLLHUP;
> +	ev.data.fd = fd;
> +	err = epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &ev);
> +	if (!ASSERT_OK(err, "epoll_ctl"))
> +		goto cleanup;
> +
> +	/* Wait for EPOLLHUP */
> +	nfds = epoll_wait(epollfd, events, 2, 5000);
> +	if (!ASSERT_EQ(nfds, 1, "epoll_wait"))
> +		goto cleanup;
> +
> +	if (!ASSERT_EQ(events[0].data.fd, fd, "epoll_wait_fd"))
> +		goto cleanup;
> +	if (!ASSERT_TRUE(events[0].events & EPOLLHUP, "events[0].events"))
> +		goto cleanup;
> +
> +cleanup:
> +	close(epollfd);
> +	bpf_link__destroy(link);
> +	struct_ops_detach__destroy(skel);
> +}
> +
>   void serial_test_struct_ops_module(void)
>   {
>   	if (test__start_subtest("test_struct_ops_load"))
> @@ -239,5 +302,7 @@ void serial_test_struct_ops_module(void)
>   		test_struct_ops_incompatible();
>   	if (test__start_subtest("test_detach_link"))
>   		test_detach_link();
> +	if (test__start_subtest("test_subsystem_detach"))
> +		test_subsystem_detach();
>   }
>   
> diff --git a/tools/testing/selftests/bpf/progs/struct_ops_detach.c b/tools/testing/selftests/bpf/progs/struct_ops_detach.c
> index aeb355b3bea3..139f9a5c5601 100644
> --- a/tools/testing/selftests/bpf/progs/struct_ops_detach.c
> +++ b/tools/testing/selftests/bpf/progs/struct_ops_detach.c
> @@ -29,3 +29,9 @@ struct bpf_testmod_ops testmod_do_detach = {
>   	.test_1 = (void *)test_1,
>   	.test_2 = (void *)test_2,
>   };
> +
> +SEC("tc")

The bpf_dummy_do_link_detach() uses a mutex. There is no lockdep splat in the test?

> +int start_detach(void *skb)
> +{
> +	return bpf_dummy_do_link_detach();
> +}
Kui-Feng Lee May 9, 2024, 5:50 a.m. UTC | #2 
On 5/8/24 16:50, Martin KaFai Lau wrote:
> On 5/6/24 10:55 PM, Kui-Feng Lee wrote:
>> Not only a user space program can detach a struct_ops link, the subsystem
>> managing a link can also detach the link. This patch add a kfunc to
>> simulate detaching a link by the subsystem managing it.
>>
>> Signed-off-by: Kui-Feng Lee <thinker.li@gmail.com>
>> ---
>>   .../selftests/bpf/bpf_testmod/bpf_testmod.c   | 21 ++++++
>>   .../bpf/prog_tests/test_struct_ops_module.c   | 65 +++++++++++++++++++
>>   .../selftests/bpf/progs/struct_ops_detach.c   |  6 ++
>>   3 files changed, 92 insertions(+)
>>
>> diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c 
>> b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
>> index c89a6414c69f..0bf1acc1767a 100644
>> --- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
>> +++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
>> @@ -502,6 +502,26 @@ __bpf_kfunc void bpf_kfunc_call_test_sleepable(void)
>>   static DEFINE_MUTEX(detach_mutex);
>>   static struct bpf_link *link_to_detach;
>> +__bpf_kfunc int bpf_dummy_do_link_detach(void)
>> +{
>> +    struct bpf_link *link;
>> +    int ret = -ENOENT;
>> +
>> +    mutex_lock(&detach_mutex);
>> +    link = link_to_detach;
>> +    /* Make sure the link is still valid by increasing its refcnt */
>> +    if (link && !atomic64_inc_not_zero(&link->refcnt))
> 
> It is better to reuse the bpf_link_inc_not_zero().

I will export this function to be used by modules.

> 
>> +        link = NULL;
>> +    mutex_unlock(&detach_mutex);
>> +
>> +    if (link) {
>> +        ret = link->ops->detach(link);
>> +        bpf_link_put(link);
>> +    }
>> +
>> +    return ret;
>> +}
>> +
>>   BTF_KFUNCS_START(bpf_testmod_check_kfunc_ids)
>>   BTF_ID_FLAGS(func, bpf_testmod_test_mod_kfunc)
>>   BTF_ID_FLAGS(func, bpf_kfunc_call_test1)
>> @@ -529,6 +549,7 @@ BTF_ID_FLAGS(func, 
>> bpf_kfunc_call_test_destructive, KF_DESTRUCTIVE)
>>   BTF_ID_FLAGS(func, bpf_kfunc_call_test_static_unused_arg)
>>   BTF_ID_FLAGS(func, bpf_kfunc_call_test_offset)
>>   BTF_ID_FLAGS(func, bpf_kfunc_call_test_sleepable, KF_SLEEPABLE)
>> +BTF_ID_FLAGS(func, bpf_dummy_do_link_detach)
> 
> It should need KF_SLEEPABLE. mutex is used.

To simplify it, spinlock will be used instead.

> 
>>   BTF_KFUNCS_END(bpf_testmod_check_kfunc_ids)
>>   static int bpf_testmod_ops_init(struct btf *btf)
>> diff --git 
>> a/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c 
>> b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c
>> index f39455b81664..9f6657b53a93 100644
>> --- a/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c
>> +++ b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c
>> @@ -229,6 +229,69 @@ static void test_detach_link(void)
>>       struct_ops_detach__destroy(skel);
>>   }
>> +/* Detach a link from the subsystem that the link was registered to */
>> +static void test_subsystem_detach(void)
>> +{
>> +    LIBBPF_OPTS(bpf_test_run_opts, topts,
>> +            .data_in = &pkt_v4,
>> +            .data_size_in = sizeof(pkt_v4));
>> +    struct epoll_event ev, events[2];
>> +    struct struct_ops_detach *skel;
>> +    struct bpf_link *link = NULL;
>> +    int fd, epollfd = -1, nfds;
>> +    int prog_fd;
>> +    int err;
>> +
>> +    skel = struct_ops_detach__open_and_load();
>> +    if (!ASSERT_OK_PTR(skel, "struct_ops_detach_open_and_load"))
>> +        return;
>> +
>> +    link = bpf_map__attach_struct_ops(skel->maps.testmod_do_detach);
>> +    if (!ASSERT_OK_PTR(link, "attach_struct_ops"))
>> +        goto cleanup;
>> +
>> +    fd = bpf_link__fd(link);
>> +    if (!ASSERT_GE(fd, 0, "link_fd"))
>> +        goto cleanup;
>> +
>> +    prog_fd = bpf_program__fd(skel->progs.start_detach);
>> +    if (!ASSERT_GE(prog_fd, 0, "start_detach_fd"))
>> +        goto cleanup;
>> +
>> +    /* Do detachment from the registered subsystem */
>> +    err = bpf_prog_test_run_opts(prog_fd, &topts);
>> +    if (!ASSERT_OK(err, "start_detach_run"))
>> +        goto cleanup;
>> +
>> +    if (!ASSERT_EQ(topts.retval, 0, "start_detach_run retval"))
>> +        goto cleanup;
>> +
>> +    epollfd = epoll_create1(0);
>> +    if (!ASSERT_GE(epollfd, 0, "epoll_create1"))
>> +        goto cleanup;
>> +
>> +    ev.events = EPOLLHUP;
>> +    ev.data.fd = fd;
>> +    err = epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &ev);
>> +    if (!ASSERT_OK(err, "epoll_ctl"))
>> +        goto cleanup;
>> +
>> +    /* Wait for EPOLLHUP */
>> +    nfds = epoll_wait(epollfd, events, 2, 5000);
>> +    if (!ASSERT_EQ(nfds, 1, "epoll_wait"))
>> +        goto cleanup;
>> +
>> +    if (!ASSERT_EQ(events[0].data.fd, fd, "epoll_wait_fd"))
>> +        goto cleanup;
>> +    if (!ASSERT_TRUE(events[0].events & EPOLLHUP, "events[0].events"))
>> +        goto cleanup;
>> +
>> +cleanup:
>> +    close(epollfd);
>> +    bpf_link__destroy(link);
>> +    struct_ops_detach__destroy(skel);
>> +}
>> +
>>   void serial_test_struct_ops_module(void)
>>   {
>>       if (test__start_subtest("test_struct_ops_load"))
>> @@ -239,5 +302,7 @@ void serial_test_struct_ops_module(void)
>>           test_struct_ops_incompatible();
>>       if (test__start_subtest("test_detach_link"))
>>           test_detach_link();
>> +    if (test__start_subtest("test_subsystem_detach"))
>> +        test_subsystem_detach();
>>   }
>> diff --git a/tools/testing/selftests/bpf/progs/struct_ops_detach.c 
>> b/tools/testing/selftests/bpf/progs/struct_ops_detach.c
>> index aeb355b3bea3..139f9a5c5601 100644
>> --- a/tools/testing/selftests/bpf/progs/struct_ops_detach.c
>> +++ b/tools/testing/selftests/bpf/progs/struct_ops_detach.c
>> @@ -29,3 +29,9 @@ struct bpf_testmod_ops testmod_do_detach = {
>>       .test_1 = (void *)test_1,
>>       .test_2 = (void *)test_2,
>>   };
>> +
>> +SEC("tc")
> 
> The bpf_dummy_do_link_detach() uses a mutex. There is no lockdep splat 
> in the test?
> 
>> +int start_detach(void *skb)
>> +{
>> +    return bpf_dummy_do_link_detach();
>> +}
>
diff mbox series

Patch

diff --git a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
index c89a6414c69f..0bf1acc1767a 100644
--- a/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
+++ b/tools/testing/selftests/bpf/bpf_testmod/bpf_testmod.c
@@ -502,6 +502,26 @@  __bpf_kfunc void bpf_kfunc_call_test_sleepable(void)
 static DEFINE_MUTEX(detach_mutex);
 static struct bpf_link *link_to_detach;
 
+__bpf_kfunc int bpf_dummy_do_link_detach(void)
+{
+	struct bpf_link *link;
+	int ret = -ENOENT;
+
+	mutex_lock(&detach_mutex);
+	link = link_to_detach;
+	/* Make sure the link is still valid by increasing its refcnt */
+	if (link && !atomic64_inc_not_zero(&link->refcnt))
+		link = NULL;
+	mutex_unlock(&detach_mutex);
+
+	if (link) {
+		ret = link->ops->detach(link);
+		bpf_link_put(link);
+	}
+
+	return ret;
+}
+
 BTF_KFUNCS_START(bpf_testmod_check_kfunc_ids)
 BTF_ID_FLAGS(func, bpf_testmod_test_mod_kfunc)
 BTF_ID_FLAGS(func, bpf_kfunc_call_test1)
@@ -529,6 +549,7 @@  BTF_ID_FLAGS(func, bpf_kfunc_call_test_destructive, KF_DESTRUCTIVE)
 BTF_ID_FLAGS(func, bpf_kfunc_call_test_static_unused_arg)
 BTF_ID_FLAGS(func, bpf_kfunc_call_test_offset)
 BTF_ID_FLAGS(func, bpf_kfunc_call_test_sleepable, KF_SLEEPABLE)
+BTF_ID_FLAGS(func, bpf_dummy_do_link_detach)
 BTF_KFUNCS_END(bpf_testmod_check_kfunc_ids)
 
 static int bpf_testmod_ops_init(struct btf *btf)
diff --git a/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c
index f39455b81664..9f6657b53a93 100644
--- a/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c
+++ b/tools/testing/selftests/bpf/prog_tests/test_struct_ops_module.c
@@ -229,6 +229,69 @@  static void test_detach_link(void)
 	struct_ops_detach__destroy(skel);
 }
 
+/* Detach a link from the subsystem that the link was registered to */
+static void test_subsystem_detach(void)
+{
+	LIBBPF_OPTS(bpf_test_run_opts, topts,
+		    .data_in = &pkt_v4,
+		    .data_size_in = sizeof(pkt_v4));
+	struct epoll_event ev, events[2];
+	struct struct_ops_detach *skel;
+	struct bpf_link *link = NULL;
+	int fd, epollfd = -1, nfds;
+	int prog_fd;
+	int err;
+
+	skel = struct_ops_detach__open_and_load();
+	if (!ASSERT_OK_PTR(skel, "struct_ops_detach_open_and_load"))
+		return;
+
+	link = bpf_map__attach_struct_ops(skel->maps.testmod_do_detach);
+	if (!ASSERT_OK_PTR(link, "attach_struct_ops"))
+		goto cleanup;
+
+	fd = bpf_link__fd(link);
+	if (!ASSERT_GE(fd, 0, "link_fd"))
+		goto cleanup;
+
+	prog_fd = bpf_program__fd(skel->progs.start_detach);
+	if (!ASSERT_GE(prog_fd, 0, "start_detach_fd"))
+		goto cleanup;
+
+	/* Do detachment from the registered subsystem */
+	err = bpf_prog_test_run_opts(prog_fd, &topts);
+	if (!ASSERT_OK(err, "start_detach_run"))
+		goto cleanup;
+
+	if (!ASSERT_EQ(topts.retval, 0, "start_detach_run retval"))
+		goto cleanup;
+
+	epollfd = epoll_create1(0);
+	if (!ASSERT_GE(epollfd, 0, "epoll_create1"))
+		goto cleanup;
+
+	ev.events = EPOLLHUP;
+	ev.data.fd = fd;
+	err = epoll_ctl(epollfd, EPOLL_CTL_ADD, fd, &ev);
+	if (!ASSERT_OK(err, "epoll_ctl"))
+		goto cleanup;
+
+	/* Wait for EPOLLHUP */
+	nfds = epoll_wait(epollfd, events, 2, 5000);
+	if (!ASSERT_EQ(nfds, 1, "epoll_wait"))
+		goto cleanup;
+
+	if (!ASSERT_EQ(events[0].data.fd, fd, "epoll_wait_fd"))
+		goto cleanup;
+	if (!ASSERT_TRUE(events[0].events & EPOLLHUP, "events[0].events"))
+		goto cleanup;
+
+cleanup:
+	close(epollfd);
+	bpf_link__destroy(link);
+	struct_ops_detach__destroy(skel);
+}
+
 void serial_test_struct_ops_module(void)
 {
 	if (test__start_subtest("test_struct_ops_load"))
@@ -239,5 +302,7 @@  void serial_test_struct_ops_module(void)
 		test_struct_ops_incompatible();
 	if (test__start_subtest("test_detach_link"))
 		test_detach_link();
+	if (test__start_subtest("test_subsystem_detach"))
+		test_subsystem_detach();
 }
 
diff --git a/tools/testing/selftests/bpf/progs/struct_ops_detach.c b/tools/testing/selftests/bpf/progs/struct_ops_detach.c
index aeb355b3bea3..139f9a5c5601 100644
--- a/tools/testing/selftests/bpf/progs/struct_ops_detach.c
+++ b/tools/testing/selftests/bpf/progs/struct_ops_detach.c
@@ -29,3 +29,9 @@  struct bpf_testmod_ops testmod_do_detach = {
 	.test_1 = (void *)test_1,
 	.test_2 = (void *)test_2,
 };
+
+SEC("tc")
+int start_detach(void *skb)
+{
+	return bpf_dummy_do_link_detach();
+}