On Sat, 2013-11-30 at 19:59 +0800, Chen Gang wrote: > On 11/29/2013 11:38 PM, Johannes Berg wrote: > > > >> +++ b/net/mac80211/tx.c > >> @@ -1814,8 +1814,9 @@ netdev_tx_t ieee80211_subif_start_xmit(struct > >> sk_buff *skb, > >> break; > >> /* fall through */ > >> case NL80211_IFTYPE_AP: > >> - if (sdata->vif.type == NL80211_IFTYPE_AP) > >> - chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf); > >> + if (sdata->vif.type != NL80211_IFTYPE_AP) > >> + goto fail_rcu; > >> + chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf); > > > > This change is completely wrong. > > > > Oh, it is. > > Hmm... for me, this work flow still can be implemented with a little > clearer way (at least it will avoid related warning): > > -------------------------diff begin------------------------------ > > diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c > index c558b24..7076128 100644 > --- a/net/mac80211/tx.c > +++ b/net/mac80211/tx.c > @@ -1810,14 +1810,14 @@ netdev_tx_t ieee80211_subif_start_xmit(struct sk_buff > *skb, > if (!chanctx_conf) > goto fail_rcu; > band = chanctx_conf->def.chan->band; > - if (sta) > - break; > - /* fall through */ > + if (!sta) > + goto try_next; > + break; > case NL80211_IFTYPE_AP: > - if (sdata->vif.type == NL80211_IFTYPE_AP) > - chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf); > + chanctx_conf = rcu_dereference(sdata->vif.chanctx_conf); > if (!chanctx_conf) > goto fail_rcu; > +try_next:
I don't think that's better than the (fairly obvious) fall-through, and has a pretty odd goto. Also, depending on the compiler, it still knows the previous case label and doesn't warn. johannes -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
