[PATCH v3 2/2] bpf: remove the do_idr_lock parameter from bpf_prog_free_id()

[Stanislav Fomichev]

On Fri, Jan 6, 2023 at 7:44 AM Paul Moore <paul at paul-moore.com> wrote:
>
> It was determined that the do_idr_lock parameter to
> bpf_prog_free_id() was not necessary as it should always be true.
>
> Suggested-by: Stanislav Fomichev <sdf at google.com>

nit: I believe it's been suggested several times by different people

Acked-by: Stanislav Fomichev <sdf at google.com>


> Signed-off-by: Paul Moore <paul at paul-moore.com>
>
> ---
> * v3
> - initial draft
> ---
>  include/linux/bpf.h  |  2 +-
>  kernel/bpf/syscall.c | 20 ++++++--------------
>  2 files changed, 7 insertions(+), 15 deletions(-)
>
> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> index 3de24cfb7a3d..634d37a599fa 100644
> --- a/include/linux/bpf.h
> +++ b/include/linux/bpf.h
> @@ -1832,7 +1832,7 @@ void bpf_prog_inc(struct bpf_prog *prog);
>  struct bpf_prog * __must_check bpf_prog_inc_not_zero(struct bpf_prog *prog);
>  void bpf_prog_put(struct bpf_prog *prog);
>
> -void bpf_prog_free_id(struct bpf_prog *prog, bool do_idr_lock);
> +void bpf_prog_free_id(struct bpf_prog *prog);
>  void bpf_map_free_id(struct bpf_map *map, bool do_idr_lock);
>
>  struct btf_field *btf_record_find(const struct btf_record *rec,
> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
> index 61bb19e81b9c..ecca9366c7a6 100644
> --- a/kernel/bpf/syscall.c
> +++ b/kernel/bpf/syscall.c
> @@ -2001,7 +2001,7 @@ static int bpf_prog_alloc_id(struct bpf_prog *prog)
>         return id > 0 ? 0 : id;
>  }
>
> -void bpf_prog_free_id(struct bpf_prog *prog, bool do_idr_lock)
> +void bpf_prog_free_id(struct bpf_prog *prog)
>  {
>         unsigned long flags;
>
> @@ -2013,18 +2013,10 @@ void bpf_prog_free_id(struct bpf_prog *prog, bool do_idr_lock)
>         if (!prog->aux->id)
>                 return;
>
> -       if (do_idr_lock)
> -               spin_lock_irqsave(&prog_idr_lock, flags);
> -       else
> -               __acquire(&prog_idr_lock);
> -
> +       spin_lock_irqsave(&prog_idr_lock, flags);
>         idr_remove(&prog_idr, prog->aux->id);
>         prog->aux->id = 0;
> -
> -       if (do_idr_lock)
> -               spin_unlock_irqrestore(&prog_idr_lock, flags);
> -       else
> -               __release(&prog_idr_lock);
> +       spin_unlock_irqrestore(&prog_idr_lock, flags);
>  }
>
>  static void __bpf_prog_put_rcu(struct rcu_head *rcu)
> @@ -2067,11 +2059,11 @@ static void bpf_prog_put_deferred(struct work_struct *work)
>         prog = aux->prog;
>         perf_event_bpf_event(prog, PERF_BPF_EVENT_PROG_UNLOAD, 0);
>         bpf_audit_prog(prog, BPF_AUDIT_UNLOAD);
> -       bpf_prog_free_id(prog, true);
> +       bpf_prog_free_id(prog);
>         __bpf_prog_put_noref(prog, true);
>  }
>
> -static void __bpf_prog_put(struct bpf_prog *prog, bool do_idr_lock)
> +static void __bpf_prog_put(struct bpf_prog *prog)
>  {
>         struct bpf_prog_aux *aux = prog->aux;
>
> @@ -2087,7 +2079,7 @@ static void __bpf_prog_put(struct bpf_prog *prog, bool do_idr_lock)
>
>  void bpf_prog_put(struct bpf_prog *prog)
>  {
> -       __bpf_prog_put(prog, true);
> +       __bpf_prog_put(prog);
>  }
>  EXPORT_SYMBOL_GPL(bpf_prog_put);
>
> --
> 2.39.0
>