Re: [PATCH v2] dax: fix dax_core_init error return code

[Jianyun Gao]

Hi Dan,

Thank you for reviewing the patch! The revised commit message looks
great to me. I'm OK with it.

Best regards,
Jianyun

On Tue, Oct 13, 2026 at 7:05 AM Alison Schofield
<alison.schofield@xxxxxxxxx> wrote:
>
> On Mon, Oct 12, 2026 at 11:18:57PM +0800, jianyungao89@xxxxxxxxx wrote:
> > From: Jianyun Gao <jianyungao89@xxxxxxxxx>
> >
> > dax_core_init() mistakenly returns 0 on error paths. Change the
> > error return to use rc so the actual error code is propagated
> > to the caller.
>
>
> Hi Jianyun,
>
> Thanks for the patch. The change looks good to me.
>
> I'd like to expand the commit message to explain the impact of the bug,
> not just describe the correction. I've proposed a revised message below.
>
>         dax: Return errors from dax_core_init()
>
>         dax_core_init() returns success when either the character device
>         number allocation or DAX bus registration fails, even though the
>         error paths have already released the initialized resources.
>
>         For modular DAX, this allows the module to remain loaded despite
>         failed initialization, leaving subsequent users and module removal
>         to access resources that have already been released.
>
>         Return the error code from the failed operation so that module
>         loading fails rather than reporting successful initialization
>         after the resources have been released.
>
> Please let me know if you're OK with the above, and I'll amend the commit
> message and merge the patch.
>
> -- Alison
>
>
> >
> > Fixes: 9567da0b408a ("device-dax: Introduce bus + driver model")
> > Cc: stable@xxxxxxxxxxxxxxx
> > Signed-off-by: Jianyun Gao <jianyungao89@xxxxxxxxx>
> > ---
> >
> > Changes in v2:
> > - Drop unnecessary goto label, keep direct return for dax_fs_init() error
> > - Add Fixes tag and Cc stable
> >
> > Link: https://lore.kernel.org/lkml/20261011132017.31131-1-jianyungao89@xxxxxxxxx/ # v1
> >
> >  drivers/dax/super.c | 2 +-
> >  1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/dax/super.c b/drivers/dax/super.c
> > index 45f84b0eb909..210f4af479f0 100644
> > --- a/drivers/dax/super.c
> > +++ b/drivers/dax/super.c
> > @@ -738,7 +738,7 @@ static int __init dax_core_init(void)
> >       unregister_chrdev_region(dax_devt, MINORMASK+1);
> >  err_chrdev:
> >       dax_fs_exit();
> > -     return 0;
> > +     return rc;
> >  }
> >
> >  static void __exit dax_core_exit(void)
> > --
> > 2.34.1
> >