On Mon, May 6, 2024 at 12:22 PM Sergey Senozhatsky
<senozhatsky@xxxxxxxxxxxx> wrote:
>
> On (24/05/05 15:48), Sergey Senozhatsky wrote:
> > On (24/05/05 14:13), Sergey Senozhatsky wrote:
> > > On (24/05/05 13:39), Sergey Senozhatsky wrote:
> > > [..]
> > > > > I guess just pick one if none were selected.
> > >
> > > How do I pick one if none were selected? Does Kconfig support
> > > something like that?
> >
> > This triggers Kconfig error:
> >
> > config ZRAM_EMPTY_BACKENDS_FIXUP
> > bool
> > depends on ZRAM && !ZRAM_BACKEND_LZO && !ZRAM_BACKEND_LZ4 && \
> > !ZRAM_BACKEND_LZ4HC && !ZRAM_BACKEND_ZSTD && \
> > !ZRAM_BACKEND_DEFLATE
> > select ZRAM_BACKEND_LZO
> >
> >
> > drivers/block/zram/Kconfig:17:error: recursive dependency detected!
> > drivers/block/zram/Kconfig:17: symbol ZRAM_BACKEND_LZO is selected by ZRAM_EMPTY_BACKENDS_FIXUP
> > drivers/block/zram/Kconfig:52: symbol ZRAM_EMPTY_BACKENDS_FIXUP depends on ZRAM_BACKEND_LZO
> >
> >
> > I'm a little surprised by this - EMPTY_BACKENDS_FIXUP does not depend
> > on ZRAM_BACKEND_LZO, it depends on NOT ZRAM_BACKEND_LZO.
> >
> > Let me Cc linux-kbuild. Kbuild folks, how do I workaround this?
>
> Is this how one does it?
>
> config ZRAM_BACKEND_LZO
> bool "lzo and lzo-rle compression support"
> depends on ZRAM
> default y if !ZRAM_BACKEND_LZ4 && !ZRAM_BACKEND_LZ4HC && \
> !ZRAM_BACKEND_ZSTD && !ZRAM_BACKEND_DEFLATE
> default n
> select LZO_COMPRESS
> select LZO_DECOMPRESS
>
>
> User still can select N and then we'll have empty backends, but
> at least default is Y if none of the algorithms were selected.
> Is it good enough?
I interpret this sentence into:
"randconfig will eventually disable all ZRAM_BACKEND_*,
causing the build error again.
Is it good enough, Arnd?"
Some possible solutions:
config ZRAM_BACKEND_FORCE_LZO
def_bool !ZRAM_BACKEND_LZ4 && !ZRAM_BACKEND_LZ4HC && \
!ZRAM_BACKEND_ZSTD && !ZRAM_BACKEND_DEFLATE
depends on ZRAM
select ZRAM_BACKEND_LZO
config ZRAM_BACKEND_LZO
bool "lzo and lzo-rle compression support"
depends on ZRAM
select LZO_COMPRESS
select LZO_DECOMPRESS
OR
config ZRAM_BACKEND_FORCE_LZO
def_bool !ZRAM_BACKEND_LZ4 && !ZRAM_BACKEND_LZ4HC && \
!ZRAM_BACKEND_ZSTD && !ZRAM_BACKEND_DEFLATE
config ZRAM_BACKEND_LZO
bool "lzo and lzo-rle compression support" if !ZRAM_BACKEND_FORCE_LZO
depends on ZRAM
default ZRAM_BACKEND_FORCE_LZO
select LZO_COMPRESS
select LZO_DECOMPRESS
BTW, "default n" you are adding are redundant.
--
Best Regards
Masahiro Yamada
