net, ppp: Report correct error code if unit allocation failed

Allocating unit from ird might return several error codes
not only -EAGAIN, so it should not be changed and returned
precisely. Same time unit release procedure should be invoked
only if device is unregistering.

Signed-off-by: Cyrill Gorcunov <gorcunov@openvz.org>
CC: Paul Mackerras <paulus@samba.org>
Signed-off-by: David S. Miller <davem@davemloft.net>

diff --git a/drivers/net/ppp_generic.c b/drivers/net/ppp_generic.c
index 09cf56d0416a8c24c78780c7eb374fcebf01cffc..39659976a1acfb1589834368aab20080c894d6eb 100644 (file)
--- a/drivers/net/ppp_generic.c
+++ b/drivers/net/ppp_generic.c
@@ -2584,16 +2584,16 @@ ppp_create_interface(struct net *net, int unit, int *retp)
         */
        dev_net_set(dev, net);
 
-       ret = -EEXIST;
        mutex_lock(&pn->all_ppp_mutex);
 
        if (unit < 0) {
                unit = unit_get(&pn->units_idr, ppp);
                if (unit < 0) {
-                       *retp = unit;
+                       ret = unit;
                        goto out2;
                }
        } else {
+               ret = -EEXIST;
                if (unit_find(&pn->units_idr, unit))
                        goto out2; /* unit already exists */
                /*
@@ -2668,10 +2668,10 @@ static void ppp_shutdown_interface(struct ppp *ppp)
                ppp->closing = 1;
                ppp_unlock(ppp);
                unregister_netdev(ppp->dev);
+               unit_put(&pn->units_idr, ppp->file.index);
        } else
                ppp_unlock(ppp);
 
-       unit_put(&pn->units_idr, ppp->file.index);
        ppp->file.dead = 1;
        ppp->owner = NULL;
        wake_up_interruptible(&ppp->file.rwait);
@@ -2859,8 +2859,7 @@ static void __exit ppp_cleanup(void)
  * by holding all_ppp_mutex
  */
 
-/* associate pointer with specified number */
-static int unit_set(struct idr *p, void *ptr, int n)
+static int __unit_alloc(struct idr *p, void *ptr, int n)
 {
        int unit, err;
 
@@ -2871,10 +2870,24 @@ again:
        }
 
        err = idr_get_new_above(p, ptr, n, &unit);
-       if (err == -EAGAIN)
-               goto again;
+       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;
 
-       if (unit != n) {
+       unit = __unit_alloc(p, ptr, n);
+       if (unit < 0)
+               return unit;
+       else if (unit != n) {
                idr_remove(p, unit);
                return -EINVAL;
        }
@@ -2885,19 +2898,7 @@ again:
 /* get new free unit number and associate pointer with it */
 static int unit_get(struct idr *p, void *ptr)
 {
-       int unit, err;
-
-again:
-       if (!idr_pre_get(p, GFP_KERNEL)) {
-               printk(KERN_ERR "PPP: No free memory for idr\n");
-               return -ENOMEM;
-       }
-
-       err = idr_get_new_above(p, ptr, 0, &unit);
-       if (err == -EAGAIN)
-               goto again;
-
-       return unit;
+       return __unit_alloc(p, ptr, 0);
 }
 
 /* put unit number back to a pool */