Re: [RFC PATCH] explicitly mark recursion count

[Jörn Engel]

On Tue, 1 June 2004 12:58:12 -0700, Linus Torvalds wrote:
> On Tue, 1 Jun 2004, Horst von Brand wrote:
> > 
> > If the comment gets out of sync, you are toast. Too easy for that to
> > happen, IMVHO.
> 
> Yes.
> 
> Recursion should be detectable automatically, the only thing you can't 
> detect easily is the reason to _break_ recursion. 

Correct.  My tool already detects recursions and prints warning, it
just cannot make out the harmful ones and gives a warning for each.

> So how about just having a simple loop finder, and then the only comment 
> you need is a simple /* max recursion: N */ for any point in the loop.

That's what I basically want, at least for trivial recursions with
only one function involved.

For a->b->c->a type recursions, I also need to identify all involved
functions in the correct order, that's where my ugly format comes
from.

RECURSION:	2
STEP:	a
STEP:	b
STEP:	c

This mean that the recursion from a to b to c and back can happen
twice at most.

Sure, the format is ugly.  If anyone really cares I can change it into
any other.  But it gets the job done, so I don't care.

> That still makes it interesting if one function is part of two loops, and
> is logically the place that breaks the recursion for one (or both - with
> different logic) of them. But does that actually happen?

"Interesting" is the wrong word, really.  Imo it doesn't make any
sense to write such code and therefore I don't want to deal with it
either.  Print a warning and be done with it.  See my output:

WARNING: multiple recursions around check_sig()

Jörn

-- 
A victorious army first wins and then seeks battle.
-- Sun Tzu
-
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/