diff mbox

[net-next-2.6] wireless: convert to use netdev_for_each_mc_addr

Message ID 20100303124249.GD2961@psychotron.lab.eng.brq.redhat.com
State Superseded, archived
Delegated to: David Miller
Headers show

Commit Message

Jiri Pirko March 3, 2010, 12:42 p.m. UTC
Wed, Mar 03, 2010 at 10:45:06AM CET, jussi.kivilinna@mbnet.fi wrote:
>Hello!
>
>Added locking broke rndis_wlan, rndis_set_oid/rndis_command sleeps.
>Also there is kmalloc(..., GFP_KERNEL) within lock/unlock.
>

Patch correcting this follows.

Subject: [net-2.6 PATCH] rndis_wlan: correct multicast_list handling

My previous patch (655ffee284dfcf9a24ac0343f3e5ee6db85b85c5) added locking in
a bad way. Because rndis_set_oid can sleep, there is need to prepare multicast
addresses into local buffer under netif_addr_lock first, then call
rndis_set_oid outside. This caused reorganizing of the whole function.

Please review.

Thanks

Jirka

Signed-off-by: Jiri Pirko <jpirko@redhat.com>
Reported-by: Jussi Kivilinna <jussi.kivilinna@mbnet.fi>

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html

Comments

Jussi Kivilinna March 3, 2010, 4:42 p.m. UTC | #1
Hello!

Quoting "Jiri Pirko" <jpirko@redhat.com>:

> +	} else if (mc_count) {
> +		int size = min(priv->multicast_size, mc_count);
> +		int i = 0;
> +
> +		mc_addrs = kmalloc(size * ETH_ALEN, GFP_ATOMIC);
...
> +	if (filter != basefilter)
> +		goto set_filter;
> +
> +	if (mc_count) {
> +		ret = rndis_set_oid(usbdev, OID_802_3_MULTICAST_LIST, mc_addrs,
> +				    mc_count * ETH_ALEN);
> +		kfree(mc_addrs);

mc_addrs was alloced by with 'size * ETH_ALEN', which might be less  
than mc_count * ETH_ALEN.

Otherwise ok, and rndis_wlan works.

  -Jussi

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Jiri Pirko March 3, 2010, 5:52 p.m. UTC | #2
Wed, Mar 03, 2010 at 05:42:56PM CET, jussi.kivilinna@mbnet.fi wrote:
>Hello!
>
>Quoting "Jiri Pirko" <jpirko@redhat.com>:
>
>>+	} else if (mc_count) {
>>+		int size = min(priv->multicast_size, mc_count);
>>+		int i = 0;
>>+
>>+		mc_addrs = kmalloc(size * ETH_ALEN, GFP_ATOMIC);
>...
>>+	if (filter != basefilter)
>>+		goto set_filter;
>>+
>>+	if (mc_count) {
>>+		ret = rndis_set_oid(usbdev, OID_802_3_MULTICAST_LIST, mc_addrs,
>>+				    mc_count * ETH_ALEN);
>>+		kfree(mc_addrs);
>
>mc_addrs was alloced by with 'size * ETH_ALEN', which might be less
>than mc_count * ETH_ALEN.

Actually it cannot. That's covered by:

if (mc_count > priv->multicast_size) {

This was also in the original code. In that case "size" can be eliminated and
"mc_addrs" can be allocated with "mc_count * ETH_ALEN".

Jussi are you ok with this?

Jirka
>
>Otherwise ok, and rndis_wlan works.
>
> -Jussi
>
--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Jussi Kivilinna March 3, 2010, 6:05 p.m. UTC | #3
Quoting "Jiri Pirko" <jpirko@redhat.com>:

> Wed, Mar 03, 2010 at 05:42:56PM CET, jussi.kivilinna@mbnet.fi wrote:
>> Hello!
>>
>> Quoting "Jiri Pirko" <jpirko@redhat.com>:
>>
>>> +	} else if (mc_count) {
>>> +		int size = min(priv->multicast_size, mc_count);
>>> +		int i = 0;
>>> +
>>> +		mc_addrs = kmalloc(size * ETH_ALEN, GFP_ATOMIC);
>> ...
>>> +	if (filter != basefilter)
>>> +		goto set_filter;
>>> +
>>> +	if (mc_count) {
>>> +		ret = rndis_set_oid(usbdev, OID_802_3_MULTICAST_LIST, mc_addrs,
>>> +				    mc_count * ETH_ALEN);
>>> +		kfree(mc_addrs);
>>
>> mc_addrs was alloced by with 'size * ETH_ALEN', which might be less
>> than mc_count * ETH_ALEN.
>
> Actually it cannot. That's covered by:
>
> if (mc_count > priv->multicast_size) {
>
> This was also in the original code. In that case "size" can be eliminated and
> "mc_addrs" can be allocated with "mc_count * ETH_ALEN".
>
> Jussi are you ok with this?
>
> Jirka

Ah, you're right. Yes, 'size' can go away, it isn't needed after all.  
I'm ok with this patch, I can fix 'size' to 'mc_count' myself later.

-Jussi

--
To unsubscribe from this list: send the line "unsubscribe netdev" in
the body of a message to majordomo@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
diff mbox

Patch

diff --git a/drivers/net/wireless/rndis_wlan.c b/drivers/net/wireless/rndis_wlan.c
index 9f6d6bf..824064b 100644
--- a/drivers/net/wireless/rndis_wlan.c
+++ b/drivers/net/wireless/rndis_wlan.c
@@ -1496,23 +1496,38 @@  static void set_multicast_list(struct usbnet *usbdev)
 {
 	struct rndis_wlan_private *priv = get_rndis_wlan_priv(usbdev);
 	struct dev_mc_list *mclist;
-	__le32 filter;
-	int ret, i, size;
-	char *buf;
+	__le32 filter, basefilter;
+	int ret;
+	char *mc_addrs = NULL;
+	int mc_count;
 
-	filter = RNDIS_PACKET_TYPE_DIRECTED | RNDIS_PACKET_TYPE_BROADCAST;
+	basefilter = filter = RNDIS_PACKET_TYPE_DIRECTED |
+			      RNDIS_PACKET_TYPE_BROADCAST;
 
-	netif_addr_lock_bh(usbdev->net);
 	if (usbdev->net->flags & IFF_PROMISC) {
 		filter |= RNDIS_PACKET_TYPE_PROMISCUOUS |
 			RNDIS_PACKET_TYPE_ALL_LOCAL;
-	} else if (usbdev->net->flags & IFF_ALLMULTI ||
-		   netdev_mc_count(usbdev->net) > priv->multicast_size) {
+	} else if (usbdev->net->flags & IFF_ALLMULTI) {
+		filter |= RNDIS_PACKET_TYPE_ALL_MULTICAST;
+	}
+
+	if (filter != basefilter)
+		goto set_filter;
+
+	/*
+	 * mc_list should be accessed holding the lock, so copy addresses to
+	 * local buffer first.
+	 */
+	netif_addr_lock_bh(usbdev->net);
+	mc_count = netdev_mc_count(usbdev->net);
+	if (mc_count > priv->multicast_size) {
 		filter |= RNDIS_PACKET_TYPE_ALL_MULTICAST;
-	} else if (!netdev_mc_empty(usbdev->net)) {
-		size = min(priv->multicast_size, netdev_mc_count(usbdev->net));
-		buf = kmalloc(size * ETH_ALEN, GFP_KERNEL);
-		if (!buf) {
+	} else if (mc_count) {
+		int size = min(priv->multicast_size, mc_count);
+		int i = 0;
+
+		mc_addrs = kmalloc(size * ETH_ALEN, GFP_ATOMIC);
+		if (!mc_addrs) {
 			netdev_warn(usbdev->net,
 				    "couldn't alloc %d bytes of memory\n",
 				    size * ETH_ALEN);
@@ -1520,27 +1535,29 @@  static void set_multicast_list(struct usbnet *usbdev)
 			return;
 		}
 
-		i = 0;
-		netdev_for_each_mc_addr(mclist, usbdev->net) {
-			if (i == size)
-				break;
-			memcpy(buf + i++ * ETH_ALEN, mclist->dmi_addr, ETH_ALEN);
-		}
+		netdev_for_each_mc_addr(mclist, usbdev->net)
+			memcpy(mc_addrs + i++ * ETH_ALEN,
+			       mclist->dmi_addr, ETH_ALEN);
+	}
+	netif_addr_unlock_bh(usbdev->net);
 
-		ret = rndis_set_oid(usbdev, OID_802_3_MULTICAST_LIST, buf,
-								i * ETH_ALEN);
-		if (ret == 0 && i > 0)
+	if (filter != basefilter)
+		goto set_filter;
+
+	if (mc_count) {
+		ret = rndis_set_oid(usbdev, OID_802_3_MULTICAST_LIST, mc_addrs,
+				    mc_count * ETH_ALEN);
+		kfree(mc_addrs);
+		if (ret == 0)
 			filter |= RNDIS_PACKET_TYPE_MULTICAST;
 		else
 			filter |= RNDIS_PACKET_TYPE_ALL_MULTICAST;
 
 		netdev_dbg(usbdev->net, "OID_802_3_MULTICAST_LIST(%d, max: %d) -> %d\n",
-			   i, priv->multicast_size, ret);
-
-		kfree(buf);
+			   mc_count, priv->multicast_size, ret);
 	}
-	netif_addr_unlock_bh(usbdev->net);
 
+set_filter:
 	ret = rndis_set_oid(usbdev, OID_GEN_CURRENT_PACKET_FILTER, &filter,
 							sizeof(filter));
 	if (ret < 0) {