ppp: convert to idr_alloc()

Convert to the much saner new idr interface.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/net/ppp/ppp_generic.c

@@ -2953,46 +2953,21 @@ static void __exit ppp_cleanup(void)
  * by holding all_ppp_mutex
  */
 
-static int __unit_alloc(struct idr *p, void *ptr, int n)
-{
-	int unit, err;
-
-again:
-	if (!idr_pre_get(p, GFP_KERNEL)) {
-		pr_err("PPP: No free memory for idr\n");
-		return -ENOMEM;
-	}
-
-	err = idr_get_new_above(p, ptr, n, &unit);
-	if (err < 0) {
-		if (err == -EAGAIN)
-			goto again;
-		return err;
-	}
-
-	return unit;
-}
-
 /* associate pointer with specified number */
 static int unit_set(struct idr *p, void *ptr, int n)
 {
 	int unit;
 
-	unit = __unit_alloc(p, ptr, n);
-	if (unit < 0)
-		return unit;
-	else if (unit != n) {
-		idr_remove(p, unit);
-		return -EINVAL;
-	}
-
+	unit = idr_alloc(p, ptr, n, n + 1, GFP_KERNEL);
+	if (unit == -ENOSPC)
+		unit = -EINVAL;
 	return unit;
 }
 
 /* get new free unit number and associate pointer with it */
 static int unit_get(struct idr *p, void *ptr)
 {
-	return __unit_alloc(p, ptr, 0);
+	return idr_alloc(p, ptr, 0, 0, GFP_KERNEL);
 }
 
 /* put unit number back to a pool */