netdev - Re: [PATCH bpf] selftest/bpf: Validate initial values of per-cpu hash elems

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Date:   Thu, 29 Oct 2020 16:37:08 -0700
From:   Song Liu <song@...nel.org>
To:     Andrii Nakryiko <andrii.nakryiko@...il.com>
Cc:     David Verbeiren <david.verbeiren@...sares.net>,
        bpf <bpf@...r.kernel.org>, Networking <netdev@...r.kernel.org>,
        Andrii Nakryiko <andrii@...nel.org>
Subject: Re: [PATCH bpf] selftest/bpf: Validate initial values of per-cpu hash elems

On Thu, Oct 29, 2020 at 3:37 PM Andrii Nakryiko
<andrii.nakryiko@...il.com> wrote:
>
> On Thu, Oct 29, 2020 at 11:36 AM Song Liu <song@...nel.org> wrote:
> >
> > On Thu, Oct 29, 2020 at 4:19 AM David Verbeiren
> > <david.verbeiren@...sares.net> wrote:
> > >
> > > Tests that when per-cpu hash map or LRU hash map elements are
> > > re-used as a result of a bpf program inserting elements, the
> > > element values for the other CPUs than the one executing the
> > > BPF code are reset to 0.

[...]

> >
> > > +                               return -1;
> > > +                       }
> > [...]
> >
> > > +
> > > +       /* delete key=1 element so it will later be re-used*/
> > > +       key = 1;
> > > +       err = bpf_map_delete_elem(map_fd, &key);
> > > +       if (CHECK(err, "bpf_map_delete_elem", "failed: %s\n", strerror(errno)))
> > > +               goto error_map;
> > > +
> > > +       /* run bpf prog that inserts new elem, re-using the slot just freed */
> > > +       err = bpf_prog_insert_elem(map_fd, key, TEST_VALUE);
> > > +       if (!ASSERT_OK(err, "bpf_prog_insert_elem"))
> > > +               goto error_map;
> >
> > What's the reason to use ASSERT_OK() instead of CHECK()?
>
> I've recently added the ASSERT_xxx() family of macros to accommodate
> most common checks and provide sensible details printing. So I now
> always prefer ASSERT() macroses, it saves a bunch of typing and time.

I see. It is definitely less typing. :)

Thanks,
Song

[...]