From: "Nicholas A. Bellinger" <nab@linux-iscsi.org>
Subject: Re: [RFC 12/12] iscsi-target: Add Makefile/Kconfig and update TCM
	top level
Date: Thu, 10 Mar 2011 00:02:21 -0800
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References: <20110308093334.GA21996@gondor.apana.org.au>
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Cc: James.Bottomley@hansenpartnership.com, hch@infradead.org,
	rdunlap@xenotime.net, linux-scsi@vger.kernel.org,
	linux-kernel@vger.kernel.org, linux-crypto@vger.kernel.org
To: Herbert Xu <herbert@gondor.apana.org.au>
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On Tue, 2011-03-08 at 17:33 +0800, Herbert Xu wrote:
> Nicholas A. Bellinger <nab@linux-iscsi.org> wrote:
> >
> >> > I should mention this is with the following .config:
> >> > 
> >> > CONFIG_CRYPTO_CRC32C=y
> >> > CONFIG_CRYPTO_CRC32C_INTEL=m
> 
> This is why you get the unoptimised version.  Had you selected
> both as built-in or both as modules, then it would have worked
> as intended.
>  

<nod>

> > What about the following to simply call request_module("crc32c_intel")
> > at module_init() time and top the extra iscsi_login_setup_crypto()
> > code..?
> 
> If we're going to do this we should do it in the crypto layer,
> and not litter every single crypto API user with such crap.
> 
> Currently we don't invoke request_module unless no implementation
> is reigstered for an algorithm.  You can change this so that it
> also invokes request_module if we have not yet done so at least
> once for that algorithm.
> 
> Patches are welcome.
> 

Ok, fair enough point..  I have addressed this with a new struct
crypto_alg->cra_check_optimized() callback in order for crc32c.ko to
have a method to call request_module("crc32c_intel.ko") after the base
software alg has been loaded.

This is working w/ CONFIG_CRYPTO_CRC32C=y + CONFIG_CRYPTO_CRC32C_INTEL=m
case and should satisfy current (and future) architecture dependent
cases for CRC32C HW offload.

Sending out a patch series for your comments shortly..

Thanks!

--nab