idr: error checking factorization

Do some code factorization in the return code analysis.
Signed-off-by: Nadia Derbey <Nadia.Derbey@bull.net>
Cc: "Paul E. McKenney" <paulmck@us.ibm.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: Jim Houston <jim.houston@comcast.net>
Cc: Pierre Peiffer <peifferp@gmail.com>
Acked-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

include/linux/idr.h

@@ -73,6 +73,12 @@ struct idr {
 }
 #define DEFINE_IDR(name)	struct idr name = IDR_INIT(name)
 
+/* Actions to be taken after a call to _idr_sub_alloc */
+#define IDR_NEED_TO_GROW -2
+#define IDR_NOMORE_SPACE -3
+
+#define _idr_rc_to_errno(rc) ((rc) == -1 ? -EAGAIN : -ENOSPC)
+
 /*
  * This is what we export.
  */

lib/idr.c

@@ -143,7 +143,7 @@ static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa)
 			/* if already at the top layer, we need to grow */
 			if (!(p = pa[l])) {
 				*starting_id = id;
-				return -2;
+				return IDR_NEED_TO_GROW;
 			}
 
 			/* If we need to go up one layer, continue the
@@ -160,7 +160,7 @@ static int sub_alloc(struct idr *idp, int *starting_id, struct idr_layer **pa)
 			id = ((id >> sh) ^ n ^ m) << sh;
 		}
 		if ((id >= MAX_ID_BIT) || (id < 0))
-			return -3;
+			return IDR_NOMORE_SPACE;
 		if (l == 0)
 			break;
 		/*
@@ -229,7 +229,7 @@ static int idr_get_empty_slot(struct idr *idp, int starting_id,
 	idp->top = p;
 	idp->layers = layers;
 	v = sub_alloc(idp, &id, pa);
-	if (v == -2)
+	if (v == IDR_NEED_TO_GROW)
 		goto build_up;
 	return(v);
 }
@@ -278,12 +278,8 @@ int idr_get_new_above(struct idr *idp, void *ptr, int starting_id, int *id)
 	 * This is a cheap hack until the IDR code can be fixed to
 	 * return proper error values.
 	 */
-	if (rv < 0) {
-		if (rv == -1)
-			return -EAGAIN;
-		else /* Will be -3 */
-			return -ENOSPC;
-	}
+	if (rv < 0)
+		return _idr_rc_to_errno(rv);
 	*id = rv;
 	return 0;
 }
@@ -313,12 +309,8 @@ int idr_get_new(struct idr *idp, void *ptr, int *id)
 	 * This is a cheap hack until the IDR code can be fixed to
 	 * return proper error values.
 	 */
-	if (rv < 0) {
-		if (rv == -1)
-			return -EAGAIN;
-		else /* Will be -3 */
-			return -ENOSPC;
-	}
+	if (rv < 0)
+		return _idr_rc_to_errno(rv);
 	*id = rv;
 	return 0;
 }
@@ -696,12 +688,8 @@ int ida_get_new_above(struct ida *ida, int starting_id, int *p_id)
  restart:
 	/* get vacant slot */
 	t = idr_get_empty_slot(&ida->idr, idr_id, pa);
-	if (t < 0) {
-		if (t == -1)
-			return -EAGAIN;
-		else /* will be -3 */
-			return -ENOSPC;
-	}
+	if (t < 0)
+		return _idr_rc_to_errno(t);
 
 	if (t * IDA_BITMAP_BITS >= MAX_ID_BIT)
 		return -ENOSPC;