Re: [PATCH net-next 3/9] bpf: pre-allocate hash map elements

[Alexei Starovoitov]

On 3/7/16 3:08 AM, Daniel Borkmann wrote:
> On 03/07/2016 02:58 AM, Alexei Starovoitov wrote:
> [...]
> > ---
> >   include/linux/bpf.h      |   1 +
> >   include/uapi/linux/bpf.h |   3 +
> >   kernel/bpf/hashtab.c     | 264
> > ++++++++++++++++++++++++++++++++++-------------
> >   kernel/bpf/syscall.c     |   2 +-
> >   4 files changed, 196 insertions(+), 74 deletions(-)
>
> Shouldn't all other map types (like array) need something like this as
> well to
> reserve this for their future flags?
>
>    if (attr->map_flags)
>      return ERR_PTR(-EINVAL);

yeah. good point. will add another patch for that.

> > diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> > index 4b070827200d..c81efb10bbb5 100644
> > --- a/include/linux/bpf.h
> > +++ b/include/linux/bpf.h
> > @@ -37,6 +37,7 @@ struct bpf_map {
> >       u32 key_size;
> >       u32 value_size;
> >       u32 max_entries;
> > +    u32 map_flags;
>
> Just naming this 'flags' doesn't work due to the anonymous struct inside
> that
> union, right? :/

yep. exactly. there is already 'flags' member there.

> > +#define BPF_F_NO_PREALLOC    (1ULL << 0)
>
> Nit: Should better be (1U << 0) as map_flags are of __u32.

right. will do.