Create a taskqueue for each wireless interface which provides a serialised

sleepable context for net80211 driver callbacks. This removes the need for USB
and firmware based drivers to roll their own code to defer the chip programming
for state changes, scan requests, channel changes and mcast/promisc updates.
When a driver callback completes the hardware state is now guaranteed to have
been updated and is in sync with net80211 layer.

This nukes around 1300 lines of code from the wireless device drivers making
them more readable and less race prone.

The net80211 layer has been updated as follows
 - all state/channel changes are serialised on the taskqueue.
 - ieee80211_new_state() always queues and can now be called from any context
 - scanning runs from a single taskq function and executes to completion. driver
   callbacks are synchronous so the channel, phy mode and rx filters are
   guaranteed to be set in hardware before probe request frames are
   transmitted.

Help and contributions from Sam Leffler.

Reviewed by:	sam

1 files changed, 33 insertions, 5 deletions

diff --git a/sys/net80211/ieee80211_var.h b/sys/net80211/ieee80211_var.h
index 55204f8..6c4ee74 100644
--- a/sys/net80211/ieee80211_var.h
+++ b/sys/net80211/ieee80211_var.h
@@ -126,7 +126,12 @@ struct ieee80211com {
 	enum ieee80211_opmode	ic_opmode;	/* operation mode */
 	struct ifmedia		ic_media;	/* interface media config */
 	struct callout		ic_inact;	/* inactivity processing */
+	struct taskqueue	*ic_tq;		/* deferred state thread */
 	struct task		ic_parent_task;	/* deferred parent processing */
+	struct task		ic_promisc_task;/* deferred promisc update */
+	struct task		ic_mcast_task;	/* deferred mcast update */
+	struct task		ic_chan_task;	/* deferred channel change */
+	struct task		ic_bmiss_task;	/* deferred beacon miss hndlr */
 
 	uint32_t		ic_flags;	/* state flags */
 	uint32_t		ic_flags_ext;	/* extended state flags */
@@ -325,8 +330,10 @@ struct ieee80211vap {
 	uint32_t		iv_htcaps;	/* HT capabilities */
 	enum ieee80211_opmode	iv_opmode;	/* operation mode */
 	enum ieee80211_state	iv_state;	/* state machine state */
-	void			(*iv_newstate_cb)(struct ieee80211vap *,
-				    enum ieee80211_state, int);
+	enum ieee80211_state	iv_nstate;	/* pending state */
+	int			iv_nstate_arg;	/* pending state arg */
+	struct task		iv_nstate_task;	/* deferred state processing */
+	struct task		iv_swbmiss_task;/* deferred iv_bmiss call */
 	struct callout		iv_mgtsend;	/* mgmt frame response timer */
 						/* inactivity timer settings */
 	int			iv_inact_init;	/* setting for new station */
@@ -519,6 +526,8 @@ MALLOC_DECLARE(M_80211_VAP);
 #define	IEEE80211_FEXT_SWBMISS	 0x00000400	/* CONF: do bmiss in s/w */
 #define	IEEE80211_FEXT_DFS	 0x00000800	/* CONF: DFS enabled */
 #define	IEEE80211_FEXT_DOTD	 0x00001000	/* CONF: 11d enabled */
+#define	IEEE80211_FEXT_STATEWAIT 0x00002000	/* STATUS: awaiting state chg */
+#define	IEEE80211_FEXT_REINIT	 0x00004000	/* STATUS: INIT state first */
 /* NB: immutable: should be set only when creating a vap */
 #define	IEEE80211_FEXT_WDSLEGACY 0x00010000	/* CONF: legacy WDS operation */
 #define	IEEE80211_FEXT_PROBECHAN 0x00020000	/* CONF: probe passive channel*/
@@ -536,9 +545,10 @@ MALLOC_DECLARE(M_80211_VAP);
 
 #define	IEEE80211_FEXT_BITS \
 	"\20\1NONHT_PR\2INACT\3SCANWAIT\4BGSCAN\5WPS\6TSN\7SCANREQ\10RESUME" \
-	"\0114ADDR\12NONEPR_PR\13SWBMISS\14DFS\15DOTD\22WDSLEGACY\23PROBECHAN" \
-	"\24HT\25AMDPU_TX\26AMPDU_TX\27AMSDU_TX\30AMSDU_RX\31USEHT40\32PUREN" \
-	"\33SHORTGI20\34SHORTGI40\35HTCOMPAT\36RIFS"
+	"\0114ADDR\12NONEPR_PR\13SWBMISS\14DFS\15DOTD\16STATEWAIT\17REINIT" \
+	"\22WDSLEGACY\23PROBECHAN\24HT\25AMDPU_TX\26AMPDU_TX\27AMSDU_TX" \
+	"\30AMSDU_RX\31USEHT40\32PUREN\33SHORTGI20\34SHORTGI40\35HTCOMPAT" \
+	"\36RIFS"
 
 #define	IEEE80211_FVEN_BITS	"\20"
 
@@ -633,6 +643,24 @@ struct ieee80211_channel *ieee80211_find_channel_byieee(struct ieee80211com *,
 int	ieee80211_setmode(struct ieee80211com *, enum ieee80211_phymode);
 enum ieee80211_phymode ieee80211_chan2mode(const struct ieee80211_channel *);
 
+/*
+ * Enqueue a task on the state thread.
+ */
+static __inline void
+ieee80211_runtask(struct ieee80211com *ic, struct task *task)
+{
+	taskqueue_enqueue(ic->ic_tq, task);
+}
+
+/*
+ * Wait for a queued task to complete.
+ */
+static __inline void
+ieee80211_draintask(struct ieee80211com *ic, struct task *task)
+{
+	taskqueue_drain(ic->ic_tq, task);
+}
+
 /* 
  * Key update synchronization methods.  XXX should not be visible.
  */