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

[Bart Van Assche <bvanassche@acm.org>]

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.