Subject: Re: [PATCH v5 5/8] io_uring/cmd: return -EOPNOTSUPP if net is disabled

From: Breno Leitao <[email-masked]>
Date: Mon, 11 Sep 2023 09:46:50 -0700

On Mon, Sep 11, 2023 at 11:53:58AM -0400, Gabriel Krisman Bertazi wrote:
> Breno Leitao <[email-masked]> writes:
> 
> > Protect io_uring_cmd_sock() to be called if CONFIG_NET is not set. If
> > network is not enabled, but io_uring is, then we want to return
> > -EOPNOTSUPP for any possible socket operation.
> >
> > This is helpful because io_uring_cmd_sock() can now call functions that
> > only exits if CONFIG_NET is enabled without having #ifdef CONFIG_NET
> > inside the function itself.
> >
> > Signed-off-by: Breno Leitao <[email-masked]>
> > ---
> >  io_uring/uring_cmd.c | 8 ++++++++
> >  1 file changed, 8 insertions(+)
> >
> > diff --git a/io_uring/uring_cmd.c b/io_uring/uring_cmd.c
> > index 60f843a357e0..a7d6a7d112b7 100644
> > --- a/io_uring/uring_cmd.c
> > +++ b/io_uring/uring_cmd.c
> > @@ -167,6 +167,7 @@ int io_uring_cmd_import_fixed(u64 ubuf, unsigned long len, int rw,
> >  }
> >  EXPORT_SYMBOL_GPL(io_uring_cmd_import_fixed);
> >  
> > +#if defined(CONFIG_NET)
> >  int io_uring_cmd_sock(struct io_uring_cmd *cmd, unsigned int issue_flags)
> >  {
> >  	struct socket *sock = cmd->file->private_data;
> > @@ -193,3 +194,10 @@ int io_uring_cmd_sock(struct io_uring_cmd *cmd, unsigned int issue_flags)
> >  	}
> >  }
> >  EXPORT_SYMBOL_GPL(io_uring_cmd_sock);
> > +#else
> > +int io_uring_cmd_sock(struct io_uring_cmd *cmd, unsigned int issue_flags)
> > +{
> > +	return -EOPNOTSUPP;
> > +}
> > +#endif
> > +
> 
> Is net/socket.c even built without CONFIG_NET? if not, you don't even need
> the alternative EOPNOTSUPP implementation.

It seems so. net/socket.o is part of obj-y:

https://github.com/torvalds/linux/blob/master/net/Makefile#L9