Re: [patch] remove artificial software max_loop limit

[Bill Davidsen <davidsen@tmr.com>]

Jan Engelhardt wrote:
> On Apr 1 2007 11:10, Ken Chen wrote:
> > On 4/1/07, Tomas M <tomas@slax.org> wrote:
> >
> > > I believe that IF you _really_ need to preserve the max_loop module 
> > > parameter, then the parameter should _not_ be ignored, rather it 
> > > should have the same function like before - to limit the loop driver 
> > > so if you use max_loop=10 for example, it should not allow loop.c to 
> > > create more than 10 loops.
> > Blame on the dual meaning of max_loop that it uses currently: to 
> > initialize a set of loop devices and as a side effect, it also sets 
> > the upper limit.  People are complaining about the former constrain, 
> > isn't it?  Does anyone uses the 2nd meaning of upper limit?
>
> Who cares if the user specifies max_loop=8 but still is able to open up 
> /dev/loop8, loop9, etc.? max_loop=X basically meant (at least to me) 
> "have at least X" loops ready.
You have just come up with a really good reason not to do unlimited 
loops. With the current limit people can count on a script mounting 
files, or similar, to neither loop for a VERY long time or to eat their 
memory. Whatever you think of programs without limit checking, this 
falls in the range of expecting an unsigned char to have a certain upper 
bound, and argues that the default limit should be the current limit and 
that setting a lower bound should work as a real and enforced limit.

If a new capability is being added, and I think it's a great one, then 
people using the capability should be the ones explicitly doing 
something different. Plauger's law of least astonishment.

--
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
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/