[PATCH 2.6.20 08/10] nfnetlink_log: shorten instances_lock holding time

[Michał Mirosław]

Shorten instances_lock window at the cost of doing unnecessary work
on the failure case. I don't know if it makes sense actually. ;>

Signed-off-by: Michał Mirosław <[EMAIL PROTECTED]>

--- linux-2.6.20/net/netfilter/nfnetlink_log.c.6        2007-02-11 
22:31:19.000000000 +0100
+++ linux-2.6.20/net/netfilter/nfnetlink_log.c  2007-02-11 22:41:18.000000000 
+0100
@@ -149,18 +149,14 @@ instance_create(u_int16_t group_num, int
 
        if (!try_module_get(THIS_MODULE)) {
                UDEBUG("aborting, could not reference own module (module 
unloading?)\n");
-               goto out_modunload;
-       }
-
-       write_lock_bh(&instances_lock); 
-       if (__instance_lookup(group_num)) {
-               UDEBUG("aborting, instance already exists\n");
-               goto out_unlock;
+               return NULL;
        }
 
        inst = kzalloc(sizeof(*inst), GFP_ATOMIC);
-       if (!inst)
-               goto out_unlock;
+       if (!inst) {
+               module_put(THIS_MODULE);
+               return NULL;
+       }
 
        INIT_HLIST_NODE(&inst->hlist);
        spin_lock_init(&inst->lock);
@@ -181,21 +177,25 @@ instance_create(u_int16_t group_num, int
        inst->copy_mode         = NFULNL_COPY_PACKET;
        inst->copy_range        = 0xffff;
 
-       hlist_add_head(&inst->hlist, 
+       write_lock_bh(&instances_lock); 
+
+       if (!__instance_lookup(group_num)) {
+               hlist_add_head(&inst->hlist, 
                       &instance_table[instance_hashfn(group_num)]);
 
-       UDEBUG("newly added node: %p, next=%p\n", &inst->hlist, 
-               inst->hlist.next);
+               UDEBUG("newly added node: %p, next=%p\n", &inst->hlist, 
+                       inst->hlist.next);
+       } else {
+               UDEBUG("aborting, instance already exists\n");
+
+               kfree(inst);
+               module_put(THIS_MODULE);
+               inst = NULL;
+       }
 
        write_unlock_bh(&instances_lock);
 
        return inst;
-
-out_unlock:
-       write_unlock_bh(&instances_lock);
-       module_put(THIS_MODULE);
-out_modunload:
-       return NULL;
 }
 
 static int __nfulnl_send(struct nfulnl_instance *inst);
-
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