Re: [PATCH v3 3/6] bpf: add BPF_PROG_ATTACH and BPF_PROG_DETACH commands

[Joe Perches]

On Mon, 2016-09-05 at 14:56 +0200, Daniel Mack wrote:
> On 08/27/2016 02:08 AM, Alexei Starovoitov wrote:
[]
> > +   switch (attr->attach_type) {
> > +   case BPF_ATTACH_TYPE_CGROUP_INET_INGRESS:
> > +   case BPF_ATTACH_TYPE_CGROUP_INET_EGRESS: {
> > +           struct cgroup *cgrp;
> > +
> > +           prog = bpf_prog_get_type(attr->attach_bpf_fd,
> > +                                    BPF_PROG_TYPE_CGROUP_SOCKET_FILTER);
> > +           if (IS_ERR(prog))
> > +                   return PTR_ERR(prog);
> > +
> > +           cgrp = cgroup_get_from_fd(attr->target_fd);
> > +           if (IS_ERR(cgrp)) {
> > +                   bpf_prog_put(prog);
> > +                   return PTR_ERR(cgrp);
> > +           }
> > +
> > +           cgroup_bpf_update(cgrp, prog, attr->attach_type);
> > +           cgroup_put(cgrp);
> > +
> > +           break;
> > +   }
> this } formatting style is confusing. The above } looks
> like it matches 'switch () {'.
> May be move 'struct cgroup *cgrp' to the top to avoid that?

This style of case statements that declare local variables
with an open brace after the case statement

        switch (bar) {
        [cases...]
        case foo: {
                local declarations;

                code...
        }
        [cases...]
        }

is used quite frequently in the kernel.
I think it's fine as is.