Subject: Re: linux-next: Tree for Oct 25 (crypto)

From: Stefan Richter <[email-masked]>
Date: Wed, 26 Oct 2011 19:15:17 +0200

On Oct 26 Randy Dunlap wrote:
> On 10/26/11 05:33, Stefan Richter wrote:
> > On Oct 26 Herbert Xu wrote:
> >> --- a/crypto/Kconfig
> >> +++ b/crypto/Kconfig
> >> @@ -103,6 +103,7 @@ config CRYPTO_MANAGER2
> >>  config CRYPTO_USER
> >>  	tristate "Userspace cryptographic algorithm configuration"
> >>  	select CRYPTO_MANAGER
> >> +	select NET
> >>  	help
> >>  	  Userapace configuration for cryptographic instantiations such as

btw, typo: "Userspace"

> >>  	  cbc(aes).
> >>
> >> Cheers,
> > 
> > If you do it this way, you also need to select everything on which NET
> > depends on.  In v3.1, that would be (only) NLATTR which in turn does not
> > depend on anything else.
[...]
> That's correct, but it's better not to "select" an entire subsystem
> like NET at all.

I agree; I add to my comment the implication that --- as a rule of thumb
--- "select" should be avoided if the option to be selected has further
dependencies.

A downside of "config A\n depends on B" is of course that potential users
of option A who are unaware of option B or not interested in B may miss how
to enable A.  Sometimes, a comment in the Kconfig file can help then.
Example (from linux-2.6.36/drivers/ieee1394/):

comment "PCILynx controller requires I2C"
	depends on IEEE1394 && I2C=n

config IEEE1394_PCILYNX
	tristate "PCILynx controller"
	depends on PCI && IEEE1394 && I2C
	select I2C_ALGOBIT
	help
	  Say Y here if you have an IEEE-1394 controller with the Texas
	  Instruments PCILynx chip.
-- 
Stefan Richter
-=====-==-== =-=- ==-=-
http://arcgraph.de/sr/