Re: [PATCH 28/31] Constify struct super_operations for 2.6.32 v1

[Al Viro <viro@ZenIV.linux.org.uk>]

On Wed, Dec 09, 2009 at 01:31:10AM +0000, Ralf Baechle wrote:
> On Sun, Dec 06, 2009 at 08:14:46AM +0300, Alexey Dobriyan wrote:
> 
> > Subject: Re: [PATCH 28/31] Constify struct super_operations for 2.6.32 v1
> > Content-Type: text/plain; charset=ISO-8859-1
> > 
> > > -   	struct inode *(*alloc_inode)(struct super_block *sb);
> > > +   	struct inode *(* const alloc_inode)(struct super_block *sb);
> > 
> > Good rule is if adding const doesn't move object from one section
> > to another, it isn't worth it.
> 
> On MIPS I've changed a few pointer arguments that frequently were abused
> by platform-specific code to const just to make sure such code blows up
> at compile time and not later in my mail folder at review time.

Seriously, folks, that looks like a fun sparse project: new type attribute
that makes pointer conversions complain (inherited by aggregates containing
one of such things) + one that restricts storage classes (again, inherited
the same way).  Another fun attribute: "no embedding into other objects".
__force casts would suppress complaints in places where e.g. noconvert
objects get allocated.