atm/nicstar: convert to idr_alloc()

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 partial success.  This
conversion keeps the bugs unchanged.
Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Chas Williams <chas@cmf.nrl.navy.mil>
Reported-by: kbuild test robot <fengguang.wu@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/atm/nicstar.c

@@ -949,11 +949,10 @@ static void free_scq(ns_dev *card, scq_info *scq, struct atm_vcc *vcc)
 static void push_rxbufs(ns_dev * card, struct sk_buff *skb)
 {
 	struct sk_buff *handle1, *handle2;
-	u32 id1 = 0, id2 = 0;
+	int id1, id2;
 	u32 addr1, addr2;
 	u32 stat;
 	unsigned long flags;
-	int err;
 
 	/* *BARF* */
 	handle2 = NULL;
@@ -1026,23 +1025,12 @@ 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);
+		id1 = idr_alloc(&card->idr, handle1, 0, 0, GFP_ATOMIC);
+		if (id1 < 0)
 			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)
+		id2 = idr_alloc(&card->idr, handle2, 0, 0, GFP_ATOMIC);
+		if (id2 < 0)
 			goto out;
 
 		spin_lock_irqsave(&card->res_lock, flags);