From: Andrii Nakryiko <andriin@fb.com>
To: <bpf@vger.kernel.org>, <netdev@vger.kernel.org>, <ast@fb.com>,
<daniel@iogearbox.net>
Cc: <andrii.nakryiko@gmail.com>, <kernel-team@fb.com>,
Andrii Nakryiko <andriin@fb.com>, Andrey Ignatov <rdna@fb.com>,
Takshak Chahande <ctakshak@fb.com>
Subject: [PATCH bpf-next 3/7] bpf, xdp: implement LINK_UPDATE for BPF XDP link
Date: Sun, 12 Jul 2020 22:12:26 -0700 [thread overview]
Message-ID: <20200713051230.3250515-4-andriin@fb.com> (raw)
In-Reply-To: <20200713051230.3250515-1-andriin@fb.com>
Add support for LINK_UPDATE command for BPF XDP link to enable reliable
replacement of underlying BPF program.
Signed-off-by: Andrii Nakryiko <andriin@fb.com>
---
net/core/dev.c | 43 +++++++++++++++++++++++++++++++++++++++++++
1 file changed, 43 insertions(+)
diff --git a/net/core/dev.c b/net/core/dev.c
index 84f755a1ec36..025687120442 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c
@@ -8973,9 +8973,52 @@ static void bpf_xdp_link_dealloc(struct bpf_link *link)
kfree(xdp_link);
}
+static int bpf_xdp_link_update(struct bpf_link *link, struct bpf_prog *new_prog,
+ struct bpf_prog *old_prog)
+{
+ struct bpf_xdp_link *xdp_link = container_of(link, struct bpf_xdp_link, link);
+ enum bpf_xdp_mode mode;
+ bpf_op_t bpf_op;
+ int err = 0;
+
+ rtnl_lock();
+
+ /* link might have been auto-released already, so fail */
+ if (!xdp_link->dev) {
+ err = -ENOLINK;
+ goto out_unlock;
+ }
+
+ if (old_prog && link->prog != old_prog) {
+ err = -EPERM;
+ goto out_unlock;
+ }
+ old_prog = link->prog;
+ if (old_prog == new_prog) {
+ /* no-op, don't disturb drivers */
+ bpf_prog_put(new_prog);
+ goto out_unlock;
+ }
+
+ mode = dev_xdp_mode(xdp_link->flags);
+ bpf_op = dev_xdp_bpf_op(xdp_link->dev, mode);
+ err = dev_xdp_install(xdp_link->dev, mode, bpf_op, NULL,
+ xdp_link->flags, new_prog);
+ if (err)
+ goto out_unlock;
+
+ old_prog = xchg(&link->prog, new_prog);
+ bpf_prog_put(old_prog);
+
+out_unlock:
+ rtnl_unlock();
+ return err;
+}
+
static const struct bpf_link_ops bpf_xdp_link_lops = {
.release = bpf_xdp_link_release,
.dealloc = bpf_xdp_link_dealloc,
+ .update_prog = bpf_xdp_link_update,
};
int bpf_xdp_link_attach(const union bpf_attr *attr, struct bpf_prog *prog)
--
2.24.1
next prev parent reply other threads:[~2020-07-13 5:13 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-07-13 5:12 [PATCH bpf-next 0/7] BPF XDP link Andrii Nakryiko
2020-07-13 5:12 ` [PATCH bpf-next 1/7] bpf, xdp: maintain info on attached XDP BPF programs in net_device Andrii Nakryiko
2020-07-13 5:12 ` [PATCH bpf-next 2/7] bpf, xdp: add bpf_link-based XDP attachment API Andrii Nakryiko
2020-07-13 5:12 ` Andrii Nakryiko [this message]
2020-07-13 5:12 ` [PATCH bpf-next 4/7] bpf: implement BPF XDP link-specific introspection APIs Andrii Nakryiko
2020-07-13 5:12 ` [PATCH bpf-next 5/7] libbpf: add support for BPF XDP link Andrii Nakryiko
2020-07-13 5:12 ` [PATCH bpf-next 6/7] selftests/bpf: add BPF XDP link selftests Andrii Nakryiko
2020-07-13 5:12 ` [PATCH bpf-next 7/7] bpf, xdp: remove XDP_QUERY_PROG and XDP_QUERY_PROG_HW XDP commands Andrii Nakryiko
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