crash_dump, nvme: select CONFIGFS_FS as built-in

Configfs can be configured as a loadable module, which causes a link-time
failure for dm-crypt crash dump support:

crash_dump_dm_crypt.c:(.text+0x3a4): undefined reference to `config_item_init_type_name'
aarch64-linux-ld: kernel/crash_dump_dm_crypt.o: in function `configfs_dmcrypt_keys_init':
crash_dump_dm_crypt.c:(.init.text+0x90): undefined reference to `config_group_init'
aarch64-linux-ld: crash_dump_dm_crypt.c:(.init.text+0xb4): undefined reference to `configfs_register_subsystem'
aarch64-linux-ld: crash_dump_dm_crypt.c:(.init.text+0xd8): undefined reference to `configfs_unregister_subsystem'

This could be avoided with a dependency on CONFIGFS_FS=y, but the
dependency has an additional problem of causing Kconfig dependency loops
since most other uses select the symbol.

Using a simple 'select CONFIGFS_FS' here in turn fails with
CONFIG_DM_CRYPT=m, because that still only causes configfs to be a
loadable module.

The only version I found that fixes this reliably uses an additional
Kconfig symbol to ensure the 'select' actually turns on configfs as
builtin, with two additional changes to avoid dependency loops with nvme
and sysfs.

There is no compile-time dependency between configfs and sysfs, so
selecting configfs from a driver with sysfs disabled does not cause link
failures, only the default /sys/kernel/config mount point will not be
created.

Link: https://lkml.kernel.org/r/[email protected]
Fixes: 6b23858fd63b ("crash_dump: make dm crypt keys persist for the kdump kernel")
Fixes: 1fb470408497 ("nvme-loop: add configfs dependency")
Signed-off-by: Arnd Bergmann <[email protected]>
Cc: Andreas Hindborg <[email protected]>
Cc: Breno Leitao <[email protected]>
Cc: Chaitanya Kulkarni <[email protected]>
Cc: Christoph Hellwig <[email protected]>
Cc: Coiby Xu <[email protected]>
Cc: Jens Axboe <[email protected]>
Cc: Sagi Grimberg <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>

0 files changed, 0 insertions, 0 deletions