1 files changed, 53 insertions, 24 deletions

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 4e57b67a91dd..4c1681bae232 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -2352,6 +2352,58 @@ static int ieee80211_set_bitrate_mask(struct wiphy *wiphy,
 	return 0;
 }
 
+static bool ieee80211_coalesce_started_roc(struct ieee80211_local *local,
+					   struct ieee80211_roc_work *new_roc,
+					   struct ieee80211_roc_work *cur_roc)
+{
+	unsigned long j = jiffies;
+	unsigned long cur_roc_end = cur_roc->hw_start_time +
+				    msecs_to_jiffies(cur_roc->duration);
+	struct ieee80211_roc_work *next_roc;
+	int new_dur;
+
+	if (WARN_ON(!cur_roc->started || !cur_roc->hw_begun))
+		return false;
+
+	if (time_after(j + IEEE80211_ROC_MIN_LEFT, cur_roc_end))
+		return false;
+
+	ieee80211_handle_roc_started(new_roc);
+
+	new_dur = new_roc->duration - jiffies_to_msecs(cur_roc_end - j);
+
+	/* cur_roc is long enough - add new_roc to the dependents list. */
+	if (new_dur <= 0) {
+		list_add_tail(&new_roc->list, &cur_roc->dependents);
+		return true;
+	}
+
+	new_roc->duration = new_dur;
+
+	/*
+	 * if cur_roc was already coalesced before, we might
+	 * want to extend the next roc instead of adding
+	 * a new one.
+	 */
+	next_roc = list_entry(cur_roc->list.next,
+			      struct ieee80211_roc_work, list);
+	if (&next_roc->list != &local->roc_list &&
+	    next_roc->chan == new_roc->chan &&
+	    next_roc->sdata == new_roc->sdata &&
+	    !WARN_ON(next_roc->started)) {
+		list_add_tail(&new_roc->list, &next_roc->dependents);
+		next_roc->duration = max(next_roc->duration,
+					 new_roc->duration);
+		next_roc->type = max(next_roc->type, new_roc->type);
+		return true;
+	}
+
+	/* add right after cur_roc */
+	list_add(&new_roc->list, &cur_roc->list);
+
+	return true;
+}
+
 static int ieee80211_start_roc_work(struct ieee80211_local *local,
 				    struct ieee80211_sub_if_data *sdata,
 				    struct ieee80211_channel *channel,
@@ -2457,8 +2509,6 @@ static int ieee80211_start_roc_work(struct ieee80211_local *local,
 
 		/* If it has already started, it's more difficult ... */
 		if (local->ops->remain_on_channel) {
-			unsigned long j = jiffies;
-
 			/*
 			 * In the offloaded ROC case, if it hasn't begun, add
 			 * this new one to the dependent list to be handled
@@ -2481,29 +2531,8 @@ static int ieee80211_start_roc_work(struct ieee80211_local *local,
 				break;
 			}
 
-			if (time_before(j + IEEE80211_ROC_MIN_LEFT,
-					tmp->hw_start_time +
-					msecs_to_jiffies(tmp->duration))) {
-				int new_dur;
-
-				ieee80211_handle_roc_started(roc);
-
-				new_dur = roc->duration -
-					  jiffies_to_msecs(tmp->hw_start_time +
-							   msecs_to_jiffies(
-								tmp->duration) -
-							   j);
-
-				if (new_dur > 0) {
-					/* add right after tmp */
-					roc->duration = new_dur;
-					list_add(&roc->list, &tmp->list);
-				} else {
-					list_add_tail(&roc->list,
-						      &tmp->dependents);
-				}
+			if (ieee80211_coalesce_started_roc(local, roc, tmp))
 				queued = true;
-			}
 		} else if (del_timer_sync(&tmp->work.timer)) {
 			unsigned long new_end;