[BUGFIX] wifi: mac80211: handle link deactivated before/during CSA

If a link has CSA that isn't active, we cannot ask the driver to
handle the CSA even if it implements that API. Additionally, if
the driver deactivates a link during CSA, schedule the work rather
than expecting it to call ieee80211_chswitch_done().

type=bugfix
fixes=Ie8453979f5805873a8411c99346bcc3810cd6476
ticket=none

Change-Id: I7886f3552865690181ae08d6026fe53530455714
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Reviewed-on: https://gerritwcs.ir.intel.com/c/iwlwifi-stack-dev/+/97820
automatic-review: iil_jenkins iil_jenkins <EC.GER.UNIX.IIL.JENKINS@INTEL.COM>
tested: iil_jenkins iil_jenkins <EC.GER.UNIX.IIL.JENKINS@INTEL.COM>
Tested-by: iil_jenkins iil_jenkins <EC.GER.UNIX.IIL.JENKINS@INTEL.COM>
Reviewed-by: Miriam Rachel Korenblit <miriam.rachel.korenblit@intel.com>
x-iwlwifi-stack-dev: 0b2babb15fd11fff51a3d2c38cda859986292486

4 files changed, 30 insertions, 7 deletions

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 5172a329e9..dd1a023759 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -978,6 +978,7 @@ struct ieee80211_link_data_managed {
 
 	bool csa_waiting_bcn;
 	bool csa_ignored_same_chan;
+	unsigned long csa_time;
 	struct wiphy_delayed_work chswitch_work;
 
 	struct wiphy_work request_smps_work;
diff --git a/net/mac80211/link.c b/net/mac80211/link.c
index 685ec66b42..4b0b939fb0 100644
--- a/net/mac80211/link.c
+++ b/net/mac80211/link.c
@@ -359,6 +359,18 @@ static int _ieee80211_set_active_links(struct ieee80211_sub_if_data *sdata,
 		ieee80211_teardown_tdls_peers(link);
 
 		ieee80211_link_release_channel(link);
+
+		/*
+		 * If CSA is (still) active while the link is deactivated,
+		 * just schedule the channel switch work for the time we
+		 * had previously calculated, and we'll take the process
+		 * from there.
+		 */
+		if (link->conf->csa_active)
+			wiphy_delayed_work_queue(local->hw.wiphy,
+						 &link->u.mgd.chswitch_work,
+						 link->u.mgd.csa_time -
+						 jiffies);
 	}
 
 	list_for_each_entry(sta, &local->sta_list, list) {
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 26d10c26a8..bb765bba18 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -2143,7 +2143,7 @@ ieee80211_sta_process_chanswitch(struct ieee80211_link_data *link,
 		.timestamp = timestamp,
 		.device_timestamp = device_timestamp,
 	};
-	unsigned long timeout;
+	unsigned long now;
 	int res;
 
 	lockdep_assert_wiphy(local->hw.wiphy);
@@ -2333,18 +2333,28 @@ ieee80211_sta_process_chanswitch(struct ieee80211_link_data *link,
 					  link->link_id, csa_ie.count,
 					  csa_ie.mode);
 
-	if (local->ops->channel_switch) {
-		/* use driver's channel switch callback */
+	/* we may have to handle timeout for deactivated link in software */
+	now = jiffies;
+	link->u.mgd.csa_time = now +
+			       TU_TO_JIFFIES((max_t(int, csa_ie.count, 1) - 1) *
+					     link->conf->beacon_int);
+
+	if (ieee80211_vif_link_active(&sdata->vif, link->link_id) &&
+	    local->ops->channel_switch) {
+		/*
+		 * Use driver's channel switch callback, the driver will
+		 * later call ieee80211_chswitch_done(). It may deactivate
+		 * the link as well, we handle that elsewhere and queue
+		 * the chswitch_work for the calculated time then.
+		 */
 		drv_channel_switch(local, sdata, &ch_switch);
 		return;
 	}
 
 	/* channel switch handled in software */
-	timeout = TU_TO_JIFFIES((max_t(int, csa_ie.count, 1) - 1) *
-				link->conf->beacon_int);
 	wiphy_delayed_work_queue(local->hw.wiphy,
 				 &link->u.mgd.chswitch_work,
-				 timeout);
+				 link->u.mgd.csa_time - now);
 	return;
  drop_connection:
 	/*
diff --git a/versions b/versions
index 717a3fcb7f..73dc94e4e3 100644
--- a/versions
+++ b/versions
@@ -2,4 +2,4 @@ BACKPORTS_VERSION="(see git)"
 BACKPORTED_KERNEL_VERSION="(see git)"
 BACKPORTED_KERNEL_NAME="iwlwifi"
 BACKPORTS_BUILD_TSTAMP=__DATE__ \" \" __TIME__
-BACKPORTS_GIT_TRACKED="iwlwifi-stack-public:master:11988:0fe9f6a7"
+BACKPORTS_GIT_TRACKED="iwlwifi-stack-public:master:11989:0b2babb1"