On 10 March 2014 09:32, Eliad Peller <eliad@xxxxxxxxxx> wrote: > On Mon, Mar 10, 2014 at 9:37 AM, Luciano Coelho > <luciano.coelho@xxxxxxxxx> wrote: >> On Sun, 2014-03-09 at 17:13 +0200, Eliad Peller wrote: >>> On Sun, Mar 9, 2014 at 4:40 PM, Luciano Coelho <luciano.coelho@xxxxxxxxx> wrote: >>> > With single-channel drivers, we need to be able to change a running >>> > chanctx if we want to use chanctx reservation. Not all drivers may be >>> > able to do this, so add a flag that indicates support for it. >>> > >>> > Changing a running chanctx can also be used as an optimization in >>> > multi-channel drivers when the context needs to be reserved for future >>> > usage. >>> > >>> > Introduce IEEE80211_CHANCTX_RESERVED chanctx mode to mark a channel as >>> > reserved so nobody else can use it (since we know it's going to >>> > change). In the future, we may allow several vifs to use the same >>> > reservation as long as they plan to use the chanctx on the same >>> > future channel. >>> > >>> > Signed-off-by: Luciano Coelho <luciano.coelho@xxxxxxxxx> >>> > --- >>> [...] >>> >>> > @@ -177,7 +198,12 @@ ieee80211_find_chanctx(struct ieee80211_local *local, >>> > list_for_each_entry(ctx, &local->chanctx_list, list) { >>> > const struct cfg80211_chan_def *compat; >>> > >>> > - if (ctx->mode == IEEE80211_CHANCTX_EXCLUSIVE) >>> > + /* We don't support chanctx reservation for multiple >>> > + * vifs yet, so don't allow reserved chanctxs to be >>> > + * reused. >>> > + */ >>> > + if ((ctx->mode == IEEE80211_CHANCTX_EXCLUSIVE) || >>> > + ieee80211_chanctx_is_reserved(local, ctx)) >>> > continue; >>> > >>> i'm not sure that's correct. >>> you might want to find a chanctx in order to use it, not only for >>> reservation. any reason to reject it in this case? >> >> At the moment we don't support multi-vifs switching at the same time, so >> we don't allow anyone else to use a chanctx while it's reserved. >> > i'm not talking about multi-vifs switching. > consider the following scenario: > sta connected on channel 40 > ap beaconing on channel 60 > > now, you want (for whatever reason) to switch the ap to channel 40. > you'll reserve the sta's chanctx, and increase its refcount (to 2). > > now a new sta vif is added, and tries to connect on channel 40. > the check above will skip the existing channel context (because it's > also reserved) although there is no reason it won't be used. Good point. I have this case covered in my multi-vif csa patches. We could transplant it into Luca's patch? Michał -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html