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-rw-r--r--drivers/net/ppp_generic.c43
1 files changed, 37 insertions, 6 deletions
diff --git a/drivers/net/ppp_generic.c b/drivers/net/ppp_generic.c
index 06b448285eb5..7b2728b8f1b7 100644
--- a/drivers/net/ppp_generic.c
+++ b/drivers/net/ppp_generic.c
@@ -250,6 +250,7 @@ static int ppp_connect_channel(struct channel *pch, int unit);
static int ppp_disconnect_channel(struct channel *pch);
static void ppp_destroy_channel(struct channel *pch);
static int unit_get(struct idr *p, void *ptr);
+static int unit_set(struct idr *p, void *ptr, int n);
static void unit_put(struct idr *p, int n);
static void *unit_find(struct idr *p, int n);
@@ -2432,11 +2433,18 @@ ppp_create_interface(int unit, int *retp)
} else {
if (unit_find(&ppp_units_idr, unit))
goto out2; /* unit already exists */
- else {
- /* darn, someone is cheating us? */
- *retp = -EINVAL;
+ /*
+ * if caller need a specified unit number
+ * lets try to satisfy him, otherwise --
+ * he should better ask us for new unit number
+ *
+ * NOTE: yes I know that returning EEXIST it's not
+ * fair but at least pppd will ask us to allocate
+ * new unit in this case so user is happy :)
+ */
+ unit = unit_set(&ppp_units_idr, ppp, unit);
+ if (unit < 0)
goto out2;
- }
}
/* Initialize the new ppp unit */
@@ -2677,14 +2685,37 @@ 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)
+{
+ 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, n, &unit);
+ if (err == -EAGAIN)
+ goto again;
+
+ if (unit != n) {
+ idr_remove(p, unit);
+ return -EINVAL;
+ }
+
+ return unit;
+}
+
/* 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) == 0) {
- printk(KERN_ERR "Out of memory expanding drawable idr\n");
+ if (!idr_pre_get(p, GFP_KERNEL)) {
+ printk(KERN_ERR "PPP: No free memory for idr\n");
return -ENOMEM;
}