Re: [PATCH v2 4/8] zram: use crypto api to check alg availability

From	Minchan Kim <minchan@kernel.org>
Newsgroups	linux.kernel
Subject	Re: [PATCH v2 4/8] zram: use crypto api to check alg availability
Date	2016-06-01 04:30 +0200
Message-ID	<rF44V-2oj-5@gated-at.bofh.it> (permalink)
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On Wed, Jun 01, 2016 at 10:07:07AM +0900, Sergey Senozhatsky wrote:
> Hello Minchan,
> 
> On (06/01/16 09:03), Minchan Kim wrote:
> [..]
> > So, if we do 'cat /sys/block/zram0/comp_algorithm", every crypto modules
> > in the backend array are loaded in memory and not unloaded until admin
> > executes rmmod? Right?
> 
> yes, I think so.

It scares me. Common case, except one we choosed, every loaded modules
will be not used. I think it's really not good. Although the wastage
might be not big now, it will be heavy as crypto comp modules are
increased.

What do you think about it?

> 
> [..]
> > If user load out-of-tree crypto compression module, what's status of
> > comp_algorithm?
> > 
> > #> insmod foo_crypto.ko
> > #> echo foo > /sys/block/zram0/comp_algorithm
> > #> cat /sys/block/zram0/comp_algorithm
> > lzo lz4 [foo]
> > ?
> 
> yes, "lzo lz4 [out-of-tree-module-name]".

Makes sense!

Thread

[PATCH v2 4/8] zram: use crypto api to check alg availability Sergey Senozhatsky <sergey.senozhatsky@gmail.com> - 2016-05-31 14:30 +0200
  Re: [PATCH v2 4/8] zram: use crypto api to check alg availability Minchan Kim <minchan@kernel.org> - 2016-06-01 02:10 +0200
    Re: [PATCH v2 4/8] zram: use crypto api to check alg availability Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2016-06-01 03:10 +0200
      Re: [PATCH v2 4/8] zram: use crypto api to check alg availability Minchan Kim <minchan@kernel.org> - 2016-06-01 04:30 +0200
        Re: [PATCH v2 4/8] zram: use crypto api to check alg availability Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2016-06-01 05:20 +0200
          Re: [PATCH v2 4/8] zram: use crypto api to check alg availability Minchan Kim <minchan@kernel.org> - 2016-06-01 08:50 +0200
            Re: [PATCH v2 4/8] zram: use crypto api to check alg availability Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com> - 2016-06-01 09:50 +0200
              Re: [PATCH v2 4/8] zram: use crypto api to check alg availability "Austin S. Hemmelgarn" <ahferroin7@gmail.com> - 2016-06-01 17:10 +0200
              Re: [PATCH v2 4/8] zram: use crypto api to check alg availability Minchan Kim <minchan@kernel.org> - 2016-06-02 04:50 +0200

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