Re: [PATCH] staging: Disable lustre file system for MIPS, SH, and XTENSA

[Christoph Hellwig <hch@infradead.org>]

On Wed, Sep 11, 2013 at 10:51:50AM +0800, Peng Tao wrote:
> I'm not fighting against removing the piece of code. But if there is a
> strong reason to keep the functionality, we need to find a way to
> implement it. The convenience of using environment variables is that
> job scheduler can set the environment and other existing applications
> don't have to change. Are there other means to do the same? ioctl and
> upcall both need application change AFAIK.

There is no use case for it, the kernel has no business looking at these
variables.  Given that you think it's not even used I don't even know
why we're having this discussion.

Talking about nasty code, the whole linux-curproc.c is highly
questionable:

 - cfs_curproc_groups_nr:
   	unused and should be removed

 - cfs_cap_raise/cfs_cap_lower/cfs_cap_raised:
   	needs to go away, modyules must not change access permissions
	on behalf of processes

 - the whole cfs_cap_t handling also needs to go away, passing around
   capabilities is not a concept the kernel supports for a reason

 - current_is_32bit:
	Code should just use is_compat_task directly.


I've just taken the time to walk through this one file, but it seems
like most of libcfs is just as bad.