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From: Yonghong Song <yhs@fb.com>
To: Andrii Nakryiko <andriin@fb.com>, <bpf@vger.kernel.org>,
	Martin KaFai Lau <kafai@fb.com>, <netdev@vger.kernel.org>
Cc: Alexei Starovoitov <ast@fb.com>,
	Daniel Borkmann <daniel@iogearbox.net>, <kernel-team@fb.com>
Subject: [PATCH bpf-next v4 04/21] bpf: support bpf tracing/iter programs for BPF_LINK_UPDATE
Date: Sat, 9 May 2020 10:59:02 -0700	[thread overview]
Message-ID: <20200509175902.2475262-1-yhs@fb.com> (raw)
In-Reply-To: <20200509175859.2474608-1-yhs@fb.com>

Added BPF_LINK_UPDATE support for tracing/iter programs.
This way, a file based bpf iterator, which holds a reference
to the link, can have its bpf program updated without
creating new files.

Acked-by: Andrii Nakryiko <andriin@fb.com>
Signed-off-by: Yonghong Song <yhs@fb.com>
---
 kernel/bpf/bpf_iter.c | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/kernel/bpf/bpf_iter.c b/kernel/bpf/bpf_iter.c
index 03f5832909db..0542a243b78c 100644
--- a/kernel/bpf/bpf_iter.c
+++ b/kernel/bpf/bpf_iter.c
@@ -23,6 +23,9 @@ struct bpf_iter_link {
 static struct list_head targets = LIST_HEAD_INIT(targets);
 static DEFINE_MUTEX(targets_mutex);
 
+/* protect bpf_iter_link changes */
+static DEFINE_MUTEX(link_mutex);
+
 int bpf_iter_reg_target(struct bpf_iter_reg *reg_info)
 {
 	struct bpf_iter_target_info *tinfo;
@@ -111,9 +114,37 @@ static void bpf_iter_link_dealloc(struct bpf_link *link)
 	kfree(iter_link);
 }
 
+static int bpf_iter_link_replace(struct bpf_link *link,
+				 struct bpf_prog *new_prog,
+				 struct bpf_prog *old_prog)
+{
+	int ret = 0;
+
+	mutex_lock(&link_mutex);
+	if (old_prog && link->prog != old_prog) {
+		ret = -EPERM;
+		goto out_unlock;
+	}
+
+	if (link->prog->type != new_prog->type ||
+	    link->prog->expected_attach_type != new_prog->expected_attach_type ||
+	    link->prog->aux->attach_btf_id != new_prog->aux->attach_btf_id) {
+		ret = -EINVAL;
+		goto out_unlock;
+	}
+
+	old_prog = xchg(&link->prog, new_prog);
+	bpf_prog_put(old_prog);
+
+out_unlock:
+	mutex_unlock(&link_mutex);
+	return ret;
+}
+
 static const struct bpf_link_ops bpf_iter_link_lops = {
 	.release = bpf_iter_link_release,
 	.dealloc = bpf_iter_link_dealloc,
+	.update_prog = bpf_iter_link_replace,
 };
 
 int bpf_iter_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
-- 
2.24.1


  parent reply	other threads:[~2020-05-09 18:00 UTC|newest]

Thread overview: 42+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-09 17:58 [PATCH bpf-next v4 00/21] bpf: implement bpf iterator for kernel data Yonghong Song
2020-05-09 17:58 ` [PATCH bpf-next v4 01/21] bpf: implement an interface to register bpf_iter targets Yonghong Song
2020-05-09 17:59 ` [PATCH bpf-next v4 02/21] bpf: allow loading of a bpf_iter program Yonghong Song
2020-05-10  0:41   ` Alexei Starovoitov
2020-05-10  5:07     ` Yonghong Song
2020-05-12 15:41     ` Yonghong Song
2020-05-12 16:25       ` Alexei Starovoitov
2020-05-12 16:29         ` Yonghong Song
2020-05-09 17:59 ` [PATCH bpf-next v4 03/21] bpf: support bpf tracing/iter programs for BPF_LINK_CREATE Yonghong Song
2020-05-09 17:59 ` Yonghong Song [this message]
2020-05-09 17:59 ` [PATCH bpf-next v4 05/21] bpf: implement bpf_seq_read() for bpf iterator Yonghong Song
2020-05-10  0:30   ` Alexei Starovoitov
2020-05-10  4:51     ` Yonghong Song
2020-05-09 17:59 ` [PATCH bpf-next v4 06/21] bpf: create anonymous " Yonghong Song
2020-05-09 17:59 ` [PATCH bpf-next v4 07/21] bpf: create file " Yonghong Song
2020-05-09 17:59 ` [PATCH bpf-next v4 08/21] bpf: implement common macros/helpers for target iterators Yonghong Song
2020-05-09 17:59 ` [PATCH bpf-next v4 09/21] bpf: add bpf_map iterator Yonghong Song
2020-05-09 17:59 ` [PATCH bpf-next v4 10/21] net: bpf: add netlink and ipv6_route bpf_iter targets Yonghong Song
2020-05-09 17:59 ` [PATCH bpf-next v4 11/21] bpf: add task and task/file iterator targets Yonghong Song
2020-05-09 17:59 ` [PATCH bpf-next v4 12/21] bpf: add PTR_TO_BTF_ID_OR_NULL support Yonghong Song
2020-05-10  0:50   ` Alexei Starovoitov
2020-05-10  5:18     ` Yonghong Song
2020-05-10 16:11       ` Alexei Starovoitov
2020-05-10 17:05         ` Yonghong Song
2020-05-09 17:59 ` [PATCH bpf-next v4 13/21] bpf: add bpf_seq_printf and bpf_seq_write helpers Yonghong Song
2020-05-09 17:59 ` [PATCH bpf-next v4 14/21] bpf: handle spilled PTR_TO_BTF_ID properly when checking stack_boundary Yonghong Song
2020-05-09 17:59 ` [PATCH bpf-next v4 15/21] bpf: support variable length array in tracing programs Yonghong Song
2020-05-09 17:59 ` [PATCH bpf-next v4 16/21] tools/libbpf: add bpf_iter support Yonghong Song
2020-05-10  0:35   ` Alexei Starovoitov
2020-05-10  5:06     ` Yonghong Song
2020-05-10 16:09       ` Alexei Starovoitov
2020-05-10 17:04         ` Yonghong Song
2020-05-09 17:59 ` [PATCH bpf-next v4 17/21] tools/libpf: add offsetof/container_of macro in bpf_helpers.h Yonghong Song
2020-05-09 17:59 ` [PATCH bpf-next v4 18/21] tools/bpftool: add bpf_iter support for bptool Yonghong Song
2020-05-09 17:59 ` [PATCH bpf-next v4 19/21] tools/bpf: selftests: add iterator programs for ipv6_route and netlink Yonghong Song
2020-05-09 17:59 ` [PATCH bpf-next v4 20/21] tools/bpf: selftests: add iter progs for bpf_map/task/task_file Yonghong Song
2020-05-09 17:59 ` [PATCH bpf-next v4 21/21] tools/bpf: selftests: add bpf_iter selftests Yonghong Song
2020-05-10  0:34   ` Alexei Starovoitov
2020-05-10  5:01     ` Yonghong Song
2020-05-10 16:14       ` Alexei Starovoitov
2020-05-10  0:27 ` [PATCH bpf-next v4 00/21] bpf: implement bpf iterator for kernel data Alexei Starovoitov
2020-05-10  4:47   ` Yonghong Song

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