[v2] Fix bio chain related issues

[PATCH v2 04/12] block: prohibit calls to bio_chain_endio

Posted by zhangshida 2 months, 1 week ago

From: Shida Zhang <zhangshida@kylinos.cn>

Now that all potential callers of bio_chain_endio have been
eliminated, completely prohibit any future calls to this function.

Suggested-by: Ming Lei <ming.lei@redhat.com>
Suggested-by: Andreas Gruenbacher <agruenba@redhat.com>
Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Shida Zhang <zhangshida@kylinos.cn>
---
 block/bio.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/block/bio.c b/block/bio.c
index aa43435c15f..2473a2c0d2f 100644
--- a/block/bio.c
+++ b/block/bio.c
@@ -323,8 +323,13 @@ static struct bio *__bio_chain_endio(struct bio *bio)
 	return parent;
 }
 
+/**
+ * This function should only be used as a flag and must never be called.
+ * If execution reaches here, it indicates a serious programming error.
+ */
 static void bio_chain_endio(struct bio *bio)
 {
+	BUG_ON(1);
 	bio_endio(bio);
 }
 
-- 
2.34.1

Re: [PATCH v2 04/12] block: prohibit calls to bio_chain_endio

Posted by Andreas Gruenbacher 2 months, 1 week ago

On Fri, Nov 28, 2025 at 9:33 AM zhangshida <starzhangzsd@gmail.com> wrote:
> From: Shida Zhang <zhangshida@kylinos.cn>
>
> Now that all potential callers of bio_chain_endio have been
> eliminated, completely prohibit any future calls to this function.
>
> Suggested-by: Ming Lei <ming.lei@redhat.com>
> Suggested-by: Andreas Gruenbacher <agruenba@redhat.com>
> Suggested-by: Christoph Hellwig <hch@infradead.org>
> Signed-off-by: Shida Zhang <zhangshida@kylinos.cn>
> ---
>  block/bio.c | 5 +++++
>  1 file changed, 5 insertions(+)
>
> diff --git a/block/bio.c b/block/bio.c
> index aa43435c15f..2473a2c0d2f 100644
> --- a/block/bio.c
> +++ b/block/bio.c
> @@ -323,8 +323,13 @@ static struct bio *__bio_chain_endio(struct bio *bio)
>         return parent;
>  }
>
> +/**
> + * This function should only be used as a flag and must never be called.
> + * If execution reaches here, it indicates a serious programming error.
> + */
>  static void bio_chain_endio(struct bio *bio)
>  {
> +       BUG_ON(1);

The below call is dead code and should be removed. With that, nothing
remains of the first patch in this queue ("block: fix incorrect logic
in bio_chain_endio") and that patch can be dropped.

>         bio_endio(bio);
>  }
>
> --
> 2.34.1
>

Thanks,
Andreas

Re: [PATCH v2 04/12] block: prohibit calls to bio_chain_endio

Posted by Stephen Zhang 2 months, 1 week ago

Andreas Gruenbacher <agruenba@redhat.com> 于2025年11月28日周五 20:58写道：
>
> On Fri, Nov 28, 2025 at 9:33 AM zhangshida <starzhangzsd@gmail.com> wrote:
> > From: Shida Zhang <zhangshida@kylinos.cn>
> >
> > Now that all potential callers of bio_chain_endio have been
> > eliminated, completely prohibit any future calls to this function.
> >
> > Suggested-by: Ming Lei <ming.lei@redhat.com>
> > Suggested-by: Andreas Gruenbacher <agruenba@redhat.com>
> > Suggested-by: Christoph Hellwig <hch@infradead.org>
> > Signed-off-by: Shida Zhang <zhangshida@kylinos.cn>
> > ---
> >  block/bio.c | 5 +++++
> >  1 file changed, 5 insertions(+)
> >
> > diff --git a/block/bio.c b/block/bio.c
> > index aa43435c15f..2473a2c0d2f 100644
> > --- a/block/bio.c
> > +++ b/block/bio.c
> > @@ -323,8 +323,13 @@ static struct bio *__bio_chain_endio(struct bio *bio)
> >         return parent;
> >  }
> >
> > +/**
> > + * This function should only be used as a flag and must never be called.
> > + * If execution reaches here, it indicates a serious programming error.
> > + */
> >  static void bio_chain_endio(struct bio *bio)
> >  {
> > +       BUG_ON(1);
>
> The below call is dead code and should be removed. With that, nothing
> remains of the first patch in this queue ("block: fix incorrect logic
> in bio_chain_endio") and that patch can be dropped.

Yeah, that makes it much clearer. I will do that.

Thanks,
Shida

>
> >         bio_endio(bio);
> >  }
> >
> > --
> > 2.34.1
> >
>
> Thanks,
> Andreas
>