netdev - [PATCH take2][NET_SCHED] cls_u32: refcounting fix for u32

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Message-ID: <20080411134818.GA3776@ff.dom.local>
Date:	Fri, 11 Apr 2008 13:48:18 +0000
From:	Jarek Poplawski <jarkao2@...il.com>
To:	Patrick McHardy <kaber@...sh.net>
Cc:	David Miller <davem@...emloft.net>,
	Jamal Hadi Salim <hadi@...erus.ca>, netdev@...r.kernel.org
Subject: [PATCH take2][NET_SCHED] cls_u32: refcounting fix for u32_delete()

On Fri, Apr 11, 2008 at 03:22:51PM +0200, Patrick McHardy wrote:
...
> I'd suggest to behave similar to qdiscs when trying to
> removing classes that are still referenced, return -EBUSY.

Of course you are right!

Jarek P.

-------------------> (take 2)

[NET_SCHED] cls_u32: refcounting fix for u32_delete()

Deleting of nonroot hnodes mostly doesn't work in u32_delete():
refcnt == 1 is expected, but such hnodes' refcnts are initialized
with 0 and charged only with "link" nodes. Now they'll start with
1 like usual. Thanks to Patrick McHardy for an improving suggestion.


Signed-off-by: Jarek Poplawski <jarkao2@...il.com>
Cc: Jamal Hadi Salim <hadi@...erus.ca>

---

diff --git a/net/sched/cls_u32.c b/net/sched/cls_u32.c
index c5c16b4..4d75544 100644
--- a/net/sched/cls_u32.c
+++ b/net/sched/cls_u32.c
@@ -411,8 +411,10 @@ static void u32_destroy(struct tcf_proto *tp)
 			}
 		}
 
-		for (ht=tp_c->hlist; ht; ht = ht->next)
+		for (ht = tp_c->hlist; ht; ht = ht->next) {
+			ht->refcnt--;
 			u32_clear_hnode(tp, ht);
+		}
 
 		while ((ht = tp_c->hlist) != NULL) {
 			tp_c->hlist = ht->next;
@@ -441,8 +443,12 @@ static int u32_delete(struct tcf_proto *tp, unsigned long arg)
 	if (tp->root == ht)
 		return -EINVAL;
 
-	if (--ht->refcnt == 0)
+	if (ht->refcnt == 1) {
+		ht->refcnt--;
 		u32_destroy_hnode(tp, ht);
+	} else {
+		return -EBUSY;
+	}
 
 	return 0;
 }
@@ -568,7 +574,7 @@ static int u32_change(struct tcf_proto *tp, unsigned long base, u32 handle,
 		if (ht == NULL)
 			return -ENOBUFS;
 		ht->tp_c = tp_c;
-		ht->refcnt = 0;
+		ht->refcnt = 1;
 		ht->divisor = divisor;
 		ht->handle = handle;
 		ht->prio = tp->prio;
--
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