On Fri, 2014-03-21 at 14:47 +0100, Michal Kazior wrote:
> Do not allocate more channel contexts than a
> driver is capable for currently matching interface
> combination.
>
> This allows the ieee80211_vif_reserve_chanctx() to
> act as a guard against breaking interface
> combinations.
>
> Signed-off-by: Michal Kazior <michal.kazior@xxxxxxxxx>
> ---
[...]
> @@ -745,13 +764,16 @@ int ieee80211_vif_reserve_chanctx(struct ieee80211_sub_if_data *sdata,
> * context, reserve our current context
> */
> new_ctx = curr_ctx;
> - } else {
> + } else if (ieee80211_can_create_new_chanctx(local)) {
> /* create a new context and reserve it */
> new_ctx = ieee80211_new_chanctx(local, chandef, mode);
> if (IS_ERR(new_ctx)) {
> ret = PTR_ERR(new_ctx);
> goto out;
> }
> + } else {
> + ret = -EBUSY;
> + goto out;
I'm not sure about this whole allowed channels counting thing. Does it
really matter what is the total number of allowed channels? I think the
actual combinations is what should be checked here.
Let's say the driver supports these combinations:
1. num_different_channels = 2; limits max 2 APs;
2. num_different_channels = 1; limits 1 AP, 1 STA;
Then you're running on a single-channel with 1 AP and 1 STA. The STA
gets a CSA to move to a new channel. If you only consider the
max_num_channels you calculated, you will think that it is okay to
switch, but it is not, because you cannot have 1 AP and 1 STA on
different channels.
Or am I missing something?
--
Luca
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