mac80211: unify SW/offload remain-on-channel

Redesign all the off-channel code, getting rid of
the generic off-channel work concept, replacing
it with a simple remain-on-channel list.

This fixes a number of small issues with the ROC
implementation:
 * offloaded remain-on-channel couldn't be queued,
   now we can queue it as well, if needed
 * in iwlwifi (the only user) offloaded ROC is
   mutually exclusive with scanning, use the new
   queue to handle that case -- I expect that it
   will later depend on a HW flag

The bigger issue though is that there's a bad bug
in the current implementation: if we get a mgmt
TX request while HW roc is active, and this new
request has a wait time, we actually schedule a
software ROC instead since we can't guarantee the
existing offloaded ROC will still be that long.
To fix this, the queuing mechanism was needed.

The queuing mechanism for offloaded ROC isn't yet
optimal, ideally we should add API to have the HW
extend the ROC if needed. We could add that later
but for now use a software implementation.

Overall, this unifies the behaviour between the
offloaded and software-implemented case as much
as possible.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 24 insertions, 65 deletions

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 8c026abcb8d9..e6cbf5b68c89 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -317,55 +317,30 @@ struct mesh_preq_queue {
 	u8 flags;
 };
 
-enum ieee80211_work_type {
-	IEEE80211_WORK_ABORT,
-	IEEE80211_WORK_REMAIN_ON_CHANNEL,
-	IEEE80211_WORK_OFFCHANNEL_TX,
-};
-
-/**
- * enum work_done_result - indicates what to do after work was done
- *
- * @WORK_DONE_DESTROY: This work item is no longer needed, destroy.
- * @WORK_DONE_REQUEUE: This work item was reset to be reused, and
- *	should be requeued.
- */
-enum work_done_result {
-	WORK_DONE_DESTROY,
-	WORK_DONE_REQUEUE,
-};
+#if HZ/100 == 0
+#define IEEE80211_ROC_MIN_LEFT	1
+#else
+#define IEEE80211_ROC_MIN_LEFT	(HZ/100)
+#endif
 
-struct ieee80211_work {
+struct ieee80211_roc_work {
 	struct list_head list;
+	struct list_head dependents;
 
-	struct rcu_head rcu_head;
+	struct delayed_work work;
 
 	struct ieee80211_sub_if_data *sdata;
 
-	enum work_done_result (*done)(struct ieee80211_work *wk,
-				      struct sk_buff *skb);
-
 	struct ieee80211_channel *chan;
 	enum nl80211_channel_type chan_type;
 
-	unsigned long timeout;
-	enum ieee80211_work_type type;
+	bool started, abort, hw_begun, notified;
 
-	bool started;
+	unsigned long hw_start_time;
 
-	union {
-		struct {
-			u32 duration;
-		} remain;
-		struct {
-			struct sk_buff *frame;
-			u32 wait;
-			bool status;
-		} offchan_tx;
-	};
-
-	size_t data_len;
-	u8 data[];
+	u32 duration, req_duration;
+	struct sk_buff *frame;
+	u64 mgmt_tx_cookie;
 };
 
 /* flags used in struct ieee80211_if_managed.flags */
@@ -848,13 +823,6 @@ struct ieee80211_local {
 	const struct ieee80211_ops *ops;
 
 	/*
-	 * work stuff, potentially off-channel (in the future)
-	 */
-	struct list_head work_list;
-	struct timer_list work_timer;
-	struct work_struct work_work;
-
-	/*
 	 * private workqueue to mac80211. mac80211 makes this accessible
 	 * via ieee80211_queue_work()
 	 */
@@ -1088,14 +1056,12 @@ struct ieee80211_local {
 	} debugfs;
 #endif
 
-	struct ieee80211_channel *hw_roc_channel;
-	struct net_device *hw_roc_dev;
-	struct sk_buff *hw_roc_skb, *hw_roc_skb_for_status;
+	/*
+	 * Remain-on-channel support
+	 */
+	struct list_head roc_list;
 	struct work_struct hw_roc_start, hw_roc_done;
-	enum nl80211_channel_type hw_roc_channel_type;
-	unsigned int hw_roc_duration;
-	u32 hw_roc_cookie;
-	bool hw_roc_for_tx;
+	unsigned long hw_roc_start_time;
 
 	struct idr ack_status_frames;
 	spinlock_t ack_status_lock;
@@ -1291,7 +1257,12 @@ void ieee80211_offchannel_stop_vifs(struct ieee80211_local *local,
 				    bool offchannel_ps_enable);
 void ieee80211_offchannel_return(struct ieee80211_local *local,
 				 bool offchannel_ps_disable);
-void ieee80211_hw_roc_setup(struct ieee80211_local *local);
+void ieee80211_roc_setup(struct ieee80211_local *local);
+void ieee80211_start_next_roc(struct ieee80211_local *local);
+void ieee80211_roc_purge(struct ieee80211_sub_if_data *sdata);
+void ieee80211_roc_notify_destroy(struct ieee80211_roc_work *roc);
+void ieee80211_sw_roc_work(struct work_struct *work);
+void ieee80211_handle_roc_started(struct ieee80211_roc_work *roc);
 
 /* interface handling */
 int ieee80211_iface_init(void);
@@ -1501,18 +1472,6 @@ u8 *ieee80211_ie_build_ht_oper(u8 *pos, struct ieee80211_sta_ht_cap *ht_cap,
 			       enum nl80211_channel_type channel_type,
 			       u16 prot_mode);
 
-/* internal work items */
-void ieee80211_work_init(struct ieee80211_local *local);
-void ieee80211_add_work(struct ieee80211_work *wk);
-void free_work(struct ieee80211_work *wk);
-void ieee80211_work_purge(struct ieee80211_sub_if_data *sdata);
-int ieee80211_wk_remain_on_channel(struct ieee80211_sub_if_data *sdata,
-				   struct ieee80211_channel *chan,
-				   enum nl80211_channel_type channel_type,
-				   unsigned int duration, u64 *cookie);
-int ieee80211_wk_cancel_remain_on_channel(
-	struct ieee80211_sub_if_data *sdata, u64 cookie);
-
 /* channel management */
 enum ieee80211_chan_mode {
 	CHAN_MODE_UNDEFINED,