Re: [PATCH 16/39] convert __bpf_prog_get() to CLASS(fd, ...)

Christian Brauner
2024-08-07T10:28:38Z

On Tue, Jul 30, 2024 at 01:16:02AM GMT, viro@kernel.org wrote:
> From: Al Viro <viro@zeniv.linux.org.uk>
>
> Irregularity here is fdput() not in the same scope as fdget();
> just fold ____bpf_prog_get() into its (only) caller and that's
> it...
>
> Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
> ---
> kernel/bpf/syscall.c | 32 +++++++++++---------------------
> 1 file changed, 11 insertions(+), 21 deletions(-)
>
> diff --git a/kernel/bpf/syscall.c b/kernel/bpf/syscall.c
> index 3093bf2cc266..c5b252c0faa8 100644
> --- a/kernel/bpf/syscall.c
> +++ b/kernel/bpf/syscall.c
> @@ -2407,18 +2407,6 @@ int bpf_prog_new_fd(struct bpf_prog *prog)
> O_RDWR | O_CLOEXEC);
> }
>
> -static struct bpf_prog *____bpf_prog_get(struct fd f)
> -{
> - if (!fd_file(f))
> - return ERR_PTR(-EBADF);
> - if (fd_file(f)->f_op != &bpf_prog_fops) {
> - fdput(f);
> - return ERR_PTR(-EINVAL);
> - }
> -
> - return fd_file(f)->private_data;
> -}
> -
> void bpf_prog_add(struct bpf_prog *prog, int i)
> {
> atomic64_add(i, &prog->aux->refcnt);
> @@ -2474,20 +2462,22 @@ bool bpf_prog_get_ok(struct bpf_prog *prog,
> static struct bpf_prog *__bpf_prog_get(u32 ufd, enum bpf_prog_type *attach_type,
> bool attach_drv)
> {
> - struct fd f = fdget(ufd);
> + CLASS(fd, f)(ufd);
> struct bpf_prog *prog;
>
> - prog = ____bpf_prog_get(f);
> - if (IS_ERR(prog))
> + if (fd_empty(f))
> + return ERR_PTR(-EBADF);
> + if (fd_file(f)->f_op != &bpf_prog_fops)
> + return ERR_PTR(-EINVAL);
> +
> + prog = fd_file(f)->private_data;
> + if (IS_ERR(prog)) // can that actually happen?
> return prog;

With or without that removed:

Reviewed-by: Christian Brauner <brauner@kernel.org>