Re: [PATCH 1/2] crypto: export crypto_alg_list and rwsem

From: Joonsoo Kim
Date: Thu Aug 13 2015 - 02:32:20 EST

On Thu, Aug 13, 2015 at 11:19:54AM +0800, Herbert Xu wrote:
> On Thu, Aug 13, 2015 at 11:24:13AM +0900, Joonsoo Kim wrote:
> > Until now, zram uses compression algorithm through direct call
> > to core algorithm function, but, it has drawback that we need to add
> > compression algorithm manually to zram. If we don't do that, we cannot
> > utilize various compression algorithms in the system. To improve this
> > situation, zram will be changed to use crypto subsystem in following
> > patch. There is one problem with this change. Zram has a interface
> > that what compression algorithm it can support. Although crypto subsystem
> > has /proc interface to search all of crypto algorithm, but, there is
> > no way to get just compression algorithm in cryto subsystem. To implement
> > it on zram-side, crypto_alg_list and rwsem should be exported so
> > this patch do it.
> >
> > Signed-off-by: Joonsoo Kim <>
> Nack. We already have a netlink interface that can be used to
> query algorithms and the type information is present in the report.
> The interface is crypto_user and should be used instead of exporting
> the raw list.

Oh... I see.

Is there any way to access netlink interface and get the output from
kernel-side? I'd like to show information through
"/sys/block/zramX/comp_algorithm", because some user program can be
broken if we change output of userspace exposed interface.

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