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>

1 files changed, 22 insertions, 21 deletions

diff --git a/drivers/net/ppp_generic.c b/drivers/net/ppp_generic.c
index 09cf56d0416a..39659976a1ac 100644
--- 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 */