MIME-Version: 1.0
References: <20230202232517.8695-1-michael.christie@oracle.com> <20230202232517.8695-5-michael.christie@oracle.com>
In-Reply-To: <20230202232517.8695-5-michael.christie@oracle.com>
From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Thu, 2 Feb 2023 16:19:57 -0800
Message-ID: <CAHk-=wjF6j264jDFcY3wgzOUA2RL2SpD2oL5BF9JqCkz3A413Q@mail.gmail.com>
Subject: Re: [PATCH v11 4/8] fork: Add USER_WORKER flag to ignore signals
To:     Mike Christie <michael.christie@oracle.com>
Cc:     hch@infradead.org, stefanha@redhat.com, jasowang@redhat.com,
        mst@redhat.com, sgarzare@redhat.com,
        virtualization@lists.linux-foundation.org, brauner@kernel.org,
        ebiederm@xmission.com, konrad.wilk@oracle.com,
        linux-kernel@vger.kernel.org, Christoph Hellwig <hch@lst.de>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

On Thu, Feb 2, 2023 at 3:25 PM Mike Christie
<michael.christie@oracle.com> wrote:
>
> +       if (args->worker_flags & USER_WORKER_SIG_IGN)
> +               ignore_signals(p);

Same comment as for the other case.

There are real reasons to avoid bitfields:

 - you can't pass addresses to them around

 - it's easier to read or assign multiple fields in one go

 - they are horrible for ABI issues due to the exact bit ordering and
padding being very subtle

but none of those issues are relevant here, where it's a kernel-internal ABI.

All these use-cases seem to actually be testing one bit at a time, and
the "assignments" are structure initializers for which named bitfields
are actually perfect and just make the initializer more legible.

            Linus