Re: [PATCH] Remove broken by design and by implementation devtmpfs maintenance disaster

From: Arjan van de Ven
Date: Fri Sep 18 2009 - 10:09:58 EST


On Fri, 18 Sep 2009 06:54:39 -0700
ebiederm@xxxxxxxxxxxx (Eric W. Biederman) wrote:

>
> > I don't understand. Udev applies the final policy including
> > permissions/ownership, just as before. There is no differrence. It's
> > just that you can bring up a box without complex userspace to
> > bootstrap /dev. And that's a big win on its own.
>
> udev is too complex to use? That sounds like a userspace bug.
>
> This I guess is where I am baffled. The argument for devtmpfs
> always seem to boil down to: udev sucks let's write some kernel
> code instead.
>
> I have been trying to ask for a long time why we can't just fix
> udev to not suck.
>
> > And things like
> > "modprobe loop; losetup /dev/loop0" will just work, which it doesn't
> > with todays async udev. Again, please make yourself familiar how
> > things work, and what the problems are.
>
> I guess I don't understand why
> modprobe loop; losetup /dev/loop0 is an interesting case.
> When you can just as easily do:
> modprobe loop; udevadm settle; losetup /dev/loop0.

frankly, modprobe should call the settle.
And not just this one, but we can use this to settle other things as
well... and then it can get an --async command line option for the
cases where you know you don't want to synchronize.


--
Arjan van de Ven Intel Open Source Technology Centre
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