Re: [PATCH 3.11-rc1] crypto: Fix boot failure duetomoduledependency.

[Tim Chen <tim.c.chen@linux.intel.com>]

On Thu, 2013-07-18 at 05:50 +0900, Tetsuo Handa wrote:
> Tim Chen wrote:
> > > Therefore, I think possible solutions are either
> > > 
> > >   (a) built-in the dependent modules
> > > 
> > >       # grep crc /lib/modules/3.11.0-rc1+/modules.dep
> > >       kernel/drivers/scsi/sd_mod.ko: kernel/lib/crc-t10dif.ko
> > >       kernel/lib/crc-t10dif.ko:
> > 
> > This approach will increase kernel size for those who are not using
> > t10dif so some people may object.  
> > BTW, The PCLMULQDQ version does not need to be build in.
> 
> sd_mod.ko must choose one from versions available as of loading sd_mod.ko.
> Although it is not needed to built-in the PCLMULQDQ version for fixing the boot
> failure, it is needed to built-in the PCLMULQDQ version for getting performance
> improvement when PCLMULQDQ is supported.

The code in crct10dif transform allocation:

crct10dif_tfm = crypto_alloc_shash("crct10dif", 0, 0)

will allocate a t10dif crypto transform with highest priority.  
So as long as the crct10dif.ko and crct10dif-pclmul.ko are loaded, 
the pclmulqdq t10dif will have a higher priority and get allocated 
and used.

Thanks.

Tim

> 
> > Your approach is quite complicated.  I think something simpler like the
> > following will work:
> 
> We cannot benefit from PCLMULQDQ. Is it acceptable for you?