Re: [PATCH 2.5.67] Update VLAN to new module semantics

From: Stephen Hemminger (shemminger@osdl.org)
Date: Wed Apr 09 2003 - 14:20:02 EST


One problem with the last patch was it did not correctly cleanup the
group stuff if try_module_get failed.

Here is a third version. It checks register_netdev() which could fail
and moves the register and try_module up to correctly handle the unwind
case.

Seems to make sense to get device registered and ref count before putting
in the group structure.

diff -urN -X dontdiff linux-2.5/net/8021q/vlan.c linux-2.5-vlan/net/8021q/vlan.c
--- linux-2.5/net/8021q/vlan.c 2003-04-03 12:13:09.000000000 -0800
+++ linux-2.5-vlan/net/8021q/vlan.c 2003-04-09 12:09:24.000000000 -0700
@@ -29,7 +29,6 @@
 #include <net/p8022.h>
 #include <net/arp.h>
 #include <linux/rtnetlink.h>
-#include <linux/brlock.h>
 #include <linux/notifier.h>
 
 #include <linux/if_vlan.h>
@@ -68,7 +67,6 @@
         .dev =NULL,
         .func = vlan_skb_recv, /* VLAN receive method */
         .data = (void *)(-1), /* Set here '(void *)1' when this code can SHARE SKBs */
- .next = NULL
 };
 
 /* End of global variables definitions. */
@@ -108,7 +106,7 @@
 }
 
 /*
- * Module 'remove' entry point.
+ * Module 'remove' enry point.
  * o delete /proc/net/router directory and static entries.
  */
 static void __exit vlan_cleanup_module(void)
@@ -231,9 +229,8 @@
                                 real_dev->vlan_rx_kill_vid(real_dev, vlan_id);
                         }
 
- br_write_lock(BR_NETPROTO_LOCK);
                         grp->vlan_devices[vlan_id] = NULL;
- br_write_unlock(BR_NETPROTO_LOCK);
+ synchronize_net();
 
 
                         /* Caller unregisters (and if necessary, puts)
@@ -266,7 +263,7 @@
                                 ret = 1;
                         }
 
- MOD_DEC_USE_COUNT;
+ module_put(THIS_MODULE);
                 }
         }
 
@@ -433,6 +430,7 @@
         /* set up method calls */
         new_dev->init = vlan_dev_init;
         new_dev->destructor = vlan_dev_destruct;
+ new_dev->owner = THIS_MODULE;
             
         /* new_dev->ifindex = 0; it will be set when added to
          * the global list.
@@ -503,6 +501,15 @@
                real_dev->ifindex);
 #endif
             
+ if (register_netdevice(new_dev))
+ goto out_free_newdev_priv;
+
+ /* NOTE: We have a reference to the real device,
+ * so hold on to the reference. May fail if we are being removed
+ */
+ if (!try_module_get(THIS_MODULE))
+ goto out_free_unregister;
+
         /* So, got the sucker initialized, now lets place
          * it into our local structure.
          */
@@ -516,7 +523,7 @@
         if (!grp) { /* need to add a new group */
                 grp = kmalloc(sizeof(struct vlan_group), GFP_KERNEL);
                 if (!grp)
- goto out_free_newdev_priv;
+ goto out_free_put;
                                         
                 /* printk(KERN_ALERT "VLAN REGISTER: Allocated new group.\n"); */
                 memset(grp, 0, sizeof(struct vlan_group));
@@ -537,18 +544,18 @@
         if (real_dev->features & NETIF_F_HW_VLAN_FILTER)
                 real_dev->vlan_rx_add_vid(real_dev, VLAN_ID);
 
- register_netdevice(new_dev);
-
         rtnl_unlock();
-
- /* NOTE: We have a reference to the real device,
- * so hold on to the reference.
- */
- MOD_INC_USE_COUNT; /* Add was a success!! */
+
+
 #ifdef VLAN_DEBUG
         printk(VLAN_DBG "Allocated new device successfully, returning.\n");
 #endif
         return new_dev;
+out_free_put:
+ module_put(THIS_MODULE);
+
+out_free_unregister:
+ unregister_netdev(new_dev);
 
 out_free_newdev_priv:
         kfree(new_dev->priv);
diff -urN -X dontdiff linux-2.5/net/8021q/vlan_dev.c linux-2.5-vlan/net/8021q/vlan_dev.c
--- linux-2.5/net/8021q/vlan_dev.c 2003-04-03 12:13:09.000000000 -0800
+++ linux-2.5-vlan/net/8021q/vlan_dev.c 2003-04-08 15:50:58.000000000 -0700
@@ -31,7 +31,6 @@
 #include <net/datalink.h>
 #include <net/p8022.h>
 #include <net/arp.h>
-#include <linux/brlock.h>
 
 #include "vlan.h"
 #include "vlanproc.h"
-
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This archive was generated by hypermail 2b29 : Tue Apr 15 2003 - 22:00:01 EST