On 4/19/21 10:26 AM, Coly Li wrote:

On 4/19/21 11:40 PM, Randy Dunlap wrote:

quoted

On 4/19/21 3:23 AM, Stephen Rothwell wrote:

quoted

Hi all,

Changes since 20210416:

on x86_64:

when
# CONFIG_BLK_DEV is not set


WARNING: unmet direct dependencies detected for LIBNVDIMM
  Depends on [n]: PHYS_ADDR_T_64BIT [=y] && HAS_IOMEM [=y] && BLK_DEV [=n]
  Selected by [y]:
  - BCACHE_NVM_PAGES [=y] && MD [=y] && BCACHE [=y] && PHYS_ADDR_T_64BIT [=y]


Full randconfig file is attached.

I need hint from kbuild expert.

My original idea to use "select LIBNVDIMM" is to avoid the
BCACHE_NVM_PAGES option to disappear if LIBNVDIMM is not enabled.
Otherwise if nvdimm driver is not configure, users won't know there is a
BCACHE_NVM_PAGES option unless they read bcache Kconfig file.

But why? That's exactly how it should work. Just use depends to set the
dependency.

But I see nvdimm's Kconfig, it uses "depends on BLK_DEV", I understand
it is acceptable that LIBNVDIMM option to disappear from "make
menuconfig" if BLK_DEV is not enabled.

For such condition, which one is the proper way to set the dependence ?
- Change "select LIBNVDIMM" and "select DAX" to "depends on LIBNVDIMM"
and "depends on DAX" in bcache Kconfig
- Or change "depends on BLK_DEV" to "select BLK_DEV" in nvdimm Kconfig.

The former.

-- 
Jens Axboe