linux-kernel - Re: [PATCH] fs/crypto: make crypto.c explicitly non-modular

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Message-ID: <20160302173748.GA9395@jaegeuk.gateway>
Date:	Wed, 2 Mar 2016 09:37:48 -0800
From:	Jaegeuk Kim <jaegeuk@...nel.org>
To:	Paul Gortmaker <paul.gortmaker@...driver.com>
Cc:	Arnd Bergmann <arnd@...db.de>, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] fs/crypto: make crypto.c explicitly non-modular

Hi Paul,

On Mon, Feb 29, 2016 at 09:31:59AM -0500, Paul Gortmaker wrote:
> [Re: [PATCH] fs/crypto: make crypto.c explicitly non-modular] On 29/02/2016 (Mon 10:56) Arnd Bergmann wrote:
> 
> > On Saturday 27 February 2016 15:20:49 Paul Gortmaker wrote:
> > > As of commit 47134e6084f70fdf4381af75d4569cec6c7ebd50 ("fs crypto:
> > > add Makefile and Kconfig") the compile of fs/crypto/crypto.c tripped
> > > my local audit for non-modules using modular infrastructure vs. their
> > > built in counterparts.
> > > 
> > > The Kconfig currently controlling compilation of this code is:
> > > 
> > > config FS_ENCRYPTION
> > >         bool "FS Encryption (Per-file encryption)"
> > > 
> > > combined with:
> > > 
> > > obj-$(CONFIG_FS_ENCRYPTION)     += crypto.o policy.o keyinfo.o
> > > 
> > > ...meaning that it currently is not being built as a module by anyone.
> > > 
> > > Lets remove the modular code that is essentially orphaned, so that
> > > when reading the driver there is no doubt it is builtin-only.
> > > 
> > > Since module_init translates to device_initcall in the non-modular
> > > case, the use of fs_initcall (which seems appropriate for fs code)
> > > means the init comes slightly earlier.  However boot testing an
> > > x86-64 defconfig didn't show this to be causing any issues.
> > > 
> > > We replace module.h with moduleparam.h since the file does declare
> > > some module parameters, and leaving them as such is currently the
> > > easiest way to remain compatible with existing boot arg use cases.
> > > 
> > 
> > So why not make the option a 'tristate' instead? It looks like
> > that was intended here, and we should always try to make all
> > code loadable as modules if possible.
> 
> It wasn't that obvious to me, and at the risk of repeating myself, I'll
> always default to making the code consistent with existing functionality
> vs. making assumptions about what was intended and implicitly adding new
> functionality that may be invalid for reasons I'd never spot.
> 
> Of course authors, and maintainers are welcome to chime in and steer it
> one way or another as per the PCI patches.

Meanwhile, I've modified and tested fscrypt as a module, as Arnd commented.
I'll submit v3 to resolve this inconsistency.
Thank you for the point that I missed.
> 
> Paul.
> --
> 
> > 
> > 	Arnd