[v2] mdev: create devices from /sys/dev (kill pre-2.6.26 support, fix mdev for everyone else)

[Isaac Dunham]

On Mon, Apr 18, 2016 at 11:31:27AM +0200, Linus Walleij wrote:
> On Wed, Apr 13, 2016 at 2:37 PM, Linus Walleij <linus.walleij at linaro.org> wrote:
> 
> (...)
> > This switches from using /sys/class as the place to look for
> > devices to create to using /sys/dev where all char and block
> > devices are listed.

In practical terms, kernels older than 2.6.26 will no longer work with
mdev -s, and devices with no class will start showing up.
(2.6.26 added /sys/dev/)

> (...)
> > ChangeLog v1->v2:
> > - Restore the subsystem environment setting behaviour by
> >   following the subsystem symlink like decribed in the
> >   commit message. This may be needed by mdev scripts.
> > - Kill of /sys/block device scanning
> > - Do not fall back to /sys/class device scanning, just scan
> >   /sys/dev
> 
> Thoughts about the v2 patch?
> 
> - Yes?
> - No?
> - Linus is an idiot?

FWIW, I'm for it, though I'd like to hear if anyone is using new busybox
with 'vendor'/'BSP' kernels that are old enough for this to be problematic,
yet new enough to need mdev (ie, from 2.6.18 or somewhat newer, to 2.6.25).

Also, bloatcheck would be interesting...I might see about that.

Thanks,
Isaac Dunham