CONFIG_SYSFS_DEPRECATED and similar issues

CONFIG_SYSFS_DEPRECATED and similar issues

[Bill Davidsen]

Just a few comments on changes like this in general. Prompted by, but 
not otherwise related to the subject.

When any new feature in the kernel requires significant changes in 
userspace, attention should be given to documenting the user items which 
must change. Now "attention" doesn't mean handwaving b.s. like "user 
programs which depend on sysfs will need to be modified." It means a 
list of which common user features need to be updated and where to find 
new ones. That's what the whole Documentation directory is for, but it's 
rarely used for such a purpose.

In the most recent case, a user tool is needed which doesn't even exist 
as a release.

The other issue is to avoid "trap door" changes, which occur when a 
kernel change requires new user tools, and the user tools will not run 
with older kernels. That includes missing major features like having a 
display and being able to mount filesystems, even if the kernel is 
technically running. When there were stable and development kernel 
series that was not so much of an issue, now that every kernel is an 
adventure it would be nice to ensure that testing a new kernel is not an 
irrevocable step.

-- 
Bill Davidsen <davidsen@tmr.com>
   "We have more to fear from the bungling of the incompetent than from
the machinations of the wicked."  - from Slashdot

Re: CONFIG_SYSFS_DEPRECATED and similar issues

[Lee Revell]

On 3/6/07, Bill Davidsen <davidsen@tmr.com> wrote:
> The other issue is to avoid "trap door" changes, which occur when a
> kernel change requires new user tools, and the user tools will not run
> with older kernels.

CONFIG_SYSFS_DEPRECATED is on by default.  So this upgrading the
kernel does not require userspace changes, unless the user changes the
config, which always has the potential to break userspace.

Users can break their systems by disabling CONFIG_SYSVIPC and
CONFIG_SYSCTL too...

Lee