Yonghong Song wrote:
> Add bpf_link support for sk_msg and sk_skb programs. We have an
> internal request to support bpf_link for sk_msg programs so user
> space can have a uniform handling with bpf_link based libbpf
> APIs. Using bpf_link based libbpf API also has a benefit which
> makes system robust by decoupling prog life cycle and
> attachment life cycle.
>
> Signed-off-by: Yonghong Song <yonghong.song@xxxxxxxxx>
> ---
> include/linux/bpf.h | 6 +
> include/linux/skmsg.h | 4 +
> include/uapi/linux/bpf.h | 5 +
> kernel/bpf/syscall.c | 4 +
> net/core/sock_map.c | 268 ++++++++++++++++++++++++++++++++-
> tools/include/uapi/linux/bpf.h | 5 +
> 6 files changed, 284 insertions(+), 8 deletions(-)
>
LGTM one question below.
> +/* Handle the following two cases:
> + * case 1: link != NULL, prog != NULL, old != NULL
> + * case 2: link != NULL, prog != NULL, old == NULL
> + */
> +static int sock_map_link_update_prog(struct bpf_link *link,
> + struct bpf_prog *prog,
> + struct bpf_prog *old)
> +{
> + const struct sockmap_link *sockmap_link = container_of(link, struct sockmap_link, link);
> + struct bpf_prog **pprog;
> + struct bpf_link **plink;
> + int ret = 0;
> +
> + mutex_lock(&sockmap_mutex);
> +
> + /* If old prog is not NULL, ensure old prog is the same as link->prog. */
> + if (old && link->prog != old) {
> + ret = -EINVAL;
> + goto out;
> + }
> + /* Ensure link->prog has the same type/attach_type as the new prog. */
> + if (link->prog->type != prog->type ||
> + link->prog->expected_attach_type != prog->expected_attach_type) {
> + ret = -EINVAL;
> + goto out;
> + }
> +
> + ret = sock_map_prog_lookup(sockmap_link->map, &pprog,
> + sockmap_link->attach_type);
> + if (ret)
> + goto out;
> +
> + /* Ensure the same link between the one in map and the passed-in. */
> + ret = sock_map_link_lookup(sockmap_link->map, &plink, link, false,
> + sockmap_link->attach_type);
> + if (ret)
> + goto out;
> +
> + if (old) {
> + ret = psock_replace_prog(pprog, prog, old);
> + goto out;
> + }
> +
> + psock_set_prog(pprog, prog);
> +
> +out:
> + if (!ret) {
> + bpf_prog_inc(prog);
> + old = xchg(&link->prog, prog);
> + bpf_prog_put(old);
Need to check old? I don't think we can clal bpf_prog_put on null?
if (old)
bpf_prog_put(old)
> + }
> + mutex_unlock(&sockmap_mutex);
> + return ret;
> +}
> +
