dev_get_by_name without dev_put

dev_get_by_name without dev_put

[fabrizio.gennari]

Every time dev_get_by_name is called, and it has returned a valid struct net_device*, dev_put should be called afterwards, because otherwise the machine hangs when the device is unregistered (since dev->refcnt > 1). However, it seems that some drivers do
not call dev_put after dev_get_by_name: for example, drivers/net/pppoe.c at line 573 and net/core/dv.c at line 168. Am I wrong?
---------------------------------------------------------
Fabrizio Gennari          tel. +39 039 203 7816
Philips Research Monza    fax. +39 039 203 7800
via G. Casati 23          fabrizio.gennari@philips.com
20052 Monza (MI) Italy    http://www.research.philips.com

[PATCH] Re: dev_get_by_name without dev_put

[Arnaldo Carvalho de Melo]

Em Wed, Jul 04, 2001 at 03:49:46PM +0200, fabrizio.gennari@philips.com escreveu:
> Every time dev_get_by_name is called, and it has returned a valid struct net_device*, dev_put should be called afterwards, because otherwise the machine hangs when the device is unregistered (since dev->refcnt > 1). However, it seems that some drivers do
> not call dev_put after dev_get_by_name: for example, drivers/net/pppoe.c at line 573 and net/core/dv.c at line 168. Am I wrong?

For pppoe (and one has to look at the set_item and see if delete_item is
needed).

- Arnaldo

--- linux-2.4.5-ac24/drivers/net/pppoe.c	Tue Jul  3 18:45:41 2001
+++ linux-2.4.5-ac24.acme/drivers/net/pppoe.c	Wed Jul  4 11:00:47 2001
@@ -567,17 +567,17 @@
 		if (!dev)
 			goto end;
 
+		po->pppoe_dev = dev;
+
 		if( ! (dev->flags & IFF_UP) )
-			goto end;
+			goto err_put;
 		memcpy(&po->pppoe_pa,
 		       &sp->sa_addr.pppoe,
 		       sizeof(struct pppoe_addr));
 
 		error = set_item(po);
 		if (error < 0)
-			goto end;
-
-		po->pppoe_dev = dev;
+			goto err_put;
 
 		po->chan.hdrlen = (sizeof(struct pppoe_hdr) +
 				   dev->hard_header_len);
@@ -586,6 +586,8 @@
 		po->chan.ops = &pppoe_chan_ops;
 
 		error = ppp_register_channel(&po->chan);
+		if (error)
+			goto err_put;
 
 		sk->state = PPPOX_CONNECTED;
 	}
@@ -595,6 +597,10 @@
  end:
 	release_sock(sk);
 	return error;
+err_put:
+	dev_put(po->pppoe_dev);
+	po->pppoe_dev = NULL;
+	goto end;
 }
 
- Arnaldo

Re: [PATCH] Re: dev_get_by_name without dev_put

[David S. Miller]

Arnaldo Carvalho de Melo writes:
 > For pppoe (and one has to look at the set_item and see if delete_item is
 > needed).

Applied, sorry for taking so long.

Later,
David S. Miller
davem@redhat.com