Re: [PATCH v5] zram: break the strict dependency from lzo

On Fri, Nov 20, 2020 at 09:10:13AM +0000, Rui Salvaterra wrote:

Hi, Minchan,

On Thu, 19 Nov 2020 at 22:26, Minchan Kim [off-list ref] wrote:

quoted

What's the purpose of ZRAM_AUTOSEL_ALGO?
If you and Sergey already discussed, sorry about the missing it.

The purpose of ZRAM_AUTOSEL_ALGO is to make sure at least one of the
required compression algorithms is enabled, either as a module or
built-in. I believe Sergey agreed with the reasoning behind it, but
he'll let us know if I misunderstood. :)

quoted

Below doesn't work for your goal?

Unfortunately, it doesn't. :( It breaks the dependency chain, allowing
you to deselect all compression algorithms in the crypto menu, and

Hi Rui,

I don't understand it. Please see below.  ZRAM_COMP_LZO_DEF select
CRYPTO_LZO, not relying on it. If system supports other CRYPTO module
it will show on choice list. Otherwise, default lzo will be always
there and select CRYPTO_LZO.

Do I miss your point?

+
+choice
+       prompt "zram default compressor"
+       default ZRAM_COMP_LZO_DEF
+       depends on ZRAM || CRYPTO_LZ4
+       help
+         a
+
+config ZRAM_COMP_LZO_DEF
+       bool "lzo"
+       select CRYPTO_LZO
+       help
+         b
+
+config ZRAM_COMP_LZ4_DEF
+       bool "lz4"
+       depends on CRYPTO_LZ4
+       help
+         c
+endchoice
+
+config ZRAM_DEF_COMP
+       string
+       default "lzo" if ZRAM_COMP_LZO_DEF
+       default "lz4" if ZRAM_COMP_LZ4_DEF