Re: [PATCH] scsi: ufs: core: Fix link error when CONFIG_RPMB=m

[Bean Huo]

On Mon, 2025-12-01 at 16:53 -0800, Bart Van Assche wrote:
> On 12/1/25 2:42 PM, Bean Huo wrote:
> > On Mon, 2025-12-01 at 12:25 -0500, Martin K. Petersen wrote:
> > > > When CONFIG_SCSI_UFSHCD=y and CONFIG_RPMB=m, the kernel fails to link
> > > > with undefined references to ufs_rpmb_probe() and ufs_rpmb_remove():
> > > > 
> > > >    ld: drivers/ufs/core/ufshcd.c:8950: undefined reference to
> > > > `ufs_rpmb_probe'
> > > >    ld: drivers/ufs/core/ufshcd.c:10505: undefined reference to
> > > > `ufs_rpmb_remove'
> > > > 
> > > > The issue occurs because IS_ENABLED(CONFIG_RPMB) evaluates to true
> > > > when CONFIG_RPMB=m, causing the header to declare the real function
> > > > prototypes.
> > > 
> > > This now breaks the modular build for me.
> > 
> > I tested both IS_BUILTIN and IS_REACHABLE for the RPMB dependencies both
> > work
> > correctly in my configuration.
> > 
> > IS_REACHABLE would provide more flexibility for module configurations, but
> > in
> > practice, I don't have experience with UFS being used as a module.
> > 
> > Would you prefer IS_REACHABLE for theoretical flexibility, or is IS_BUILTIN
> > acceptable given the typical UFS built-in configuration?
> 
> Hi Martin and Bean,
> 
> Unless someone comes up with a better solution, I propose to apply this
> patch before sending a pull request to Linus and look into making RPMB
> tristate again at a later time:
> 
> diff --git a/drivers/misc/Kconfig b/drivers/misc/Kconfig
> index 9d1de68dee27..e0b7f8fb6ecb 100644
> --- a/drivers/misc/Kconfig
> +++ b/drivers/misc/Kconfig
> @@ -105,7 +105,7 @@ config PHANTOM
>           say N here.
> 
>   config RPMB
> -       tristate "RPMB partition interface"
> +       bool "RPMB partition interface"
>         depends on MMC || SCSI_UFSHCD
>         help
>           Unified RPMB unit interface for RPMB capable devices such as eMMC
> and
> 
> Thanks,
> 
> Bart.

Hi Bart, Martin, (and Jens - adding you to this thread),

Bart, thanks for the proposed solution to change RPMB from tristate
to bool. This makes sense given our use case that UFS is typically
built-in, and RPMB should follow the same pattern.


Hi Jens, 

we wanted to make sure you're aware of this proposed change. The reasoning is:
1, avoids module dependency complexity between UFS and RPMB
2, matches typical usage where both are built-in

Let me know if there are concerns with making RPMB bool instead of tristate.


Kind regards,
Bean