While rebasing this patches to send series out, I noticed that mesh CSA
was also recently merged, so I'll have to take care of that too. But I
decided to send these out anyway, so review can start.
I'll send a v4 with mesh taken into consideration as well.
Heheh, this started as a simple 2 liner patch, and look where we are
now. :D
--
Cheers,
Luca.
On Fri, 2013-11-08 at 16:39 +0200, Luciano Coelho wrote:
> A beacon should never have a Channel Switch Announcement information
> element with a count of 0, because a count of 1 means switch just
> before the next beacon. So, if a count of 0 was valid in a beacon, it
> would have been transmitted in the next channel already, which is
> useless. A CSA count equal to zero is only meaningful in action
> frames or probe_responses.
>
> Fix the ieee80211_csa_is_complete() and ieee80211_update_csa()
> functions accordingly.
>
> Signed-off-by: Luciano Coelho <luciano.coelho@xxxxxxxxx>
> ---
> In v2, updated the documentation to reflect the change. This is going
> to be sent to linux-wireless for comments from the community too.
>
> In v3, removed the part of the documentation that belongs in the next
> patch.
>
> include/net/mac80211.h | 8 ++++----
> net/mac80211/tx.c | 10 +++++++---
> 2 files changed, 11 insertions(+), 7 deletions(-)
>
> diff --git a/include/net/mac80211.h b/include/net/mac80211.h
> index 7ceed99..ec6ed6d 100644
> --- a/include/net/mac80211.h
> +++ b/include/net/mac80211.h
> @@ -2680,10 +2680,10 @@ enum ieee80211_roc_type {
> * @channel_switch_beacon: Starts a channel switch to a new channel.
> * Beacons are modified to include CSA or ECSA IEs before calling this
> * function. The corresponding count fields in these IEs must be
> - * decremented, and when they reach zero the driver must call
> + * decremented, and when they reach 1 the driver must call
> * ieee80211_csa_finish(). Drivers which use ieee80211_beacon_get()
> * get the csa counter decremented by mac80211, but must check if it is
> - * zero using ieee80211_csa_is_complete() after the beacon has been
> + * 1 using ieee80211_csa_is_complete() after the beacon has been
> * transmitted and then call ieee80211_csa_finish().
> *
> * @join_ibss: Join an IBSS (on an IBSS interface); this is called after all
> @@ -3383,13 +3383,13 @@ static inline struct sk_buff *ieee80211_beacon_get(struct ieee80211_hw *hw,
> * @vif: &struct ieee80211_vif pointer from the add_interface callback.
> *
> * After a channel switch announcement was scheduled and the counter in this
> - * announcement hit zero, this function must be called by the driver to
> + * announcement hits 1, this function must be called by the driver to
> * notify mac80211 that the channel can be changed.
> */
> void ieee80211_csa_finish(struct ieee80211_vif *vif);
>
> /**
> - * ieee80211_csa_is_complete - find out if counters reached zero
> + * ieee80211_csa_is_complete - find out if counters reached 1
> * @vif: &struct ieee80211_vif pointer from the add_interface callback.
> *
> * This function returns whether the channel switch counters reached zero.
> diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
> index c558b24..57d9feb 100644
> --- a/net/mac80211/tx.c
> +++ b/net/mac80211/tx.c
> @@ -2409,8 +2409,12 @@ static void ieee80211_update_csa(struct ieee80211_sub_if_data *sdata,
> if (WARN_ON(counter_offset_beacon >= beacon_data_len))
> return;
>
> - /* warn if the driver did not check for/react to csa completeness */
> - if (WARN_ON(beacon_data[counter_offset_beacon] == 0))
> + /* Warn if the driver did not check for/react to csa
> + * completeness. A beacon with CSA counter set to 0 should
> + * never occur, because a counter of 1 means switch just
> + * before the next beacon.
> + */
> + if (WARN_ON(beacon_data[counter_offset_beacon] == 1))
> return;
>
> beacon_data[counter_offset_beacon]--;
> @@ -2476,7 +2480,7 @@ bool ieee80211_csa_is_complete(struct ieee80211_vif *vif)
> if (WARN_ON(counter_beacon > beacon_data_len))
> goto out;
>
> - if (beacon_data[counter_beacon] == 0)
> + if (beacon_data[counter_beacon] == 1)
> ret = true;
> out:
> rcu_read_unlock();
--
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