Re: mac80211: support P2P Device abstraction

[Johannes Berg <johannes@sipsolutions.net>]

Hi Dan,

> The patch f142c6b906da: "mac80211: support P2P Device abstraction" 
> from Jun 18, 2012, leads to the following Smatch complaint:
> 
> net/mac80211/iface.c:1168 ieee80211_setup_sdata()
> 	 error: we previously assumed 'sdata->dev' could be null (see line 1134)
> 
> net/mac80211/iface.c
>   1133		/* only monitor/p2p-device differ */
>   1134		if (sdata->dev) {
>                     ^^^^^^^^^^
> New test.
> 
>   1135			sdata->dev->netdev_ops = &ieee80211_dataif_ops;
>   1136			sdata->dev->type = ARPHRD_ETHER;
>   1137		}
> 
> [snip]
> 
>   1167		case NL80211_IFTYPE_MONITOR:
>   1168			sdata->dev->type = ARPHRD_IEEE80211_RADIOTAP;
>                         ^^^^^^^^^^^^
> Old dereference.

Thanks. I'm aware of the warning (I run smatch), but sdata->dev can only
be NULL in "case NL80211_IFTYPE_P2P_DEVICE", so adding an extra check in
the monitor case didn't seem worthwhile.

It might have been better to use sdata->vif.type != P2P_DEVICE in the
new test I guess, but then it wouldn't be extensible to new interface
types like Bluetooth AMP.

johannes