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

[chas williams - CONTRACTOR <chas@cmf.nrl.navy.mil>]

I don't quite understand your comment.  idr_pre_get() returns 0 in the
case of failure.

On Sat,  2 Feb 2013 17:20:10 -0800
Tejun Heo <tj@kernel.org> wrote:

> Convert to the much saner new idr interface.  The existing code looks
> buggy to me - ID 0 is treated as no-ID but allocation specifies 0 as
> lower limit and there's no error handling after parial success.  This
> conversion keeps the bugs unchanged.
> 
> Only compile tested.
> 
> Signed-off-by: Tejun Heo <tj@kernel.org>
> Cc: Chas Williams <chas@cmf.nrl.navy.mil>
> Cc: netdev@vger.kernel.org
> ---
> This patch depends on an earlier idr changes and I think it would be
> best to route these together through -mm.  Please holler if there's
> any objection.  Thanks.
> 
>  drivers/atm/nicstar.c | 27 ++++++++++++---------------
>  1 file changed, 12 insertions(+), 15 deletions(-)
> 
> diff --git a/drivers/atm/nicstar.c b/drivers/atm/nicstar.c
> index 628787e..7fd6834 100644
> --- a/drivers/atm/nicstar.c
> +++ b/drivers/atm/nicstar.c
> @@ -1026,24 +1026,21 @@ static void push_rxbufs(ns_dev * card, struct sk_buff *skb)
>  				card->lbfqc += 2;
>  		}
>  
> -		do {
> -			if (!idr_pre_get(&card->idr, GFP_ATOMIC)) {
> -				printk(KERN_ERR
> -				       "nicstar%d: no free memory for idr\n",
> -				       card->index);
> +		if (!id1) {
> +			id1 = idr_alloc(&card->idr, handle1, 0, 0, GFP_ATOMIC);
> +			if (id1 < 0) {
> +				err = id1;
>  				goto out;
>  			}
> +		}
>  
> -			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);
> -
> -		} while (err == -EAGAIN);
> -
> -		if (err)
> -			goto out;
> +		if (!id2) {
> +			id2 = idr_alloc(&card->idr, handle2, 0, 0, GFP_ATOMIC);
> +			if (id2 < 0) {
> +				err = id2;
> +				goto out;
> +			}
> +		}
>  
>  		spin_lock_irqsave(&card->res_lock, flags);
>  		while (CMD_BUSY(card)) ;