linux-kernel - Re: [PATCH 5/7] zram: use crypto api to check alg availability

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Date:	Mon, 30 May 2016 13:57:23 +0900
From:	Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
To:	Minchan Kim <minchan@...nel.org>
Cc:	Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
	Herbert Xu <herbert@...dor.apana.org.au>,
	Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Joonsoo Kim <iamjoonsoo.kim@....com>,
	linux-kernel@...r.kernel.org
Subject: Re: [PATCH 5/7] zram: use crypto api to check alg availability

Hello Minchan,

On (05/30/16 13:47), Minchan Kim wrote:
[..]
> > can do, sure: make find_backend() depend on crypto_has_comp() only,
> > *may be* printk a message when we have a mismatch in backends array
> > and crypto_has_comp(). but not really sure about the latter one.
> 
> Me, too. We don't need to warn about that. Instead, we should allow loading
> other algorithm which doesn't live in backend array more clearly.
> We need to update documentation to clear it out.

yes, entirely forgot to update the Documentation.

> > > So, from now on, users should be aware of the compression naming and
> > > load module by oneself. It's not kind but I hope admins already knows
> > > what cryto compressor they have.
> > 
> > um, I'm not in love with this approach.
> > 
> > what admins? zram users may be completely unaware of the existence of
> > the crypto API and the kernel rebuild process. for some people switching
> > to new zram will be a matter of "apt-get upgrade/pacman -Syu", not
> > "git am ...; make menuconfig; make -j...". this looks like a major step
> > back. keeping this dummy list of compressing backends around does not take
> > a lot of effort, especially if we will make it unimportant for find_backend()
> > and only use it for that nice user-friendly `cat /zram/comp_algorithm`
> > output.
> 
> I am not against with it. Instead, please clear it out to write down docuement
> "comp_algorithm is just optional so user can load any new algorithm like this
>  blah blah"

ok, will do.

thanks.

	-ss