On Sat, 2013-11-30 at 22:02 +0800, Chen Gang wrote: > >>> 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. > >> > > > > Yeah, fall-through is obvious. But check 'A' again just near by "case A" > > seems a little strange, and some of compilers (or some of versions) are > > really not quit smart enough to know it is not a warning. > > > > Sorry, the paragraph above may lead misunderstanding, I repeated again: > > - fall-through is obvious (although I did not notice it, originally). > > - Check 'A' again just near by "case A" seems a little strange. > > - Some compilers aren't quit smart enough to know 'chanctx_conf' is OK.
I know. If you have any good ideas of how to make it more obvious to the compiler, I'm all ears, I just don't like any of the solutions offered so far (and you aren't the first to do so either) :-) FWIW, I find the label to be odd because if you're familiar with the code then AP/AP_VLAN *should* be identical except for two special things that are now linearly & neatly handled in the code (the first being the 4-addr station, the second the chanctx assignment which always has to be done regardless of 4-addr). IMHO the == check after case should be enough to make a human reader take a closer look. I understand that you didn't and that's OK since you were just trying to squelch compile warnings, but I don't see that this one warrants much attention. 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/
