Re: [PATCH 09/62] atm/nicstar: convert to idr_alloc()

[Tejun Heo <tj@kernel.org>]

Hello, Chas.

On Mon, Feb 04, 2013 at 09:04:10AM -0500, chas williams - CONTRACTOR wrote:
> I don't quite understand your comment.  idr_pre_get() returns 0 in the
> case of failure.

So, if you do the following,

	int id1 = 0, id2 = 0;

	if (!id1)
		err = idr_get_new_above(&card->idr, handle1, 0, &id1);
	if (!id2 && err == 0)
		err = idr_get_new_above(&card->idr, handle2, 0, &id2);
	if (err)
		goto out;
									    
You have no way of telling whether id1/2 are allocated or not.  0 is
the special "not allocated" value but it also is a valid ID.  The
error path should be freeing id1/2 if either of them has been
allocated but it doesn't and can't with 0 as the non-allocated value.

Thanks.

-- 
tejun