[RFC v2] initial channel context implementation

[RFC v2] initial channel context implementation

[Michal Kazior]

Hi,

Here's my respin of channel contexts patches. Thanks for the
review on the previous version.

Changes in short:

 * renamed to chanctx (to avoid very_long_structure_names)
 * pub/priv part added (and drv_priv)
 * new mutex added
 * channel contexts are a linked list
 * tracing added

Next step would be to refactor mac80211 codepaths to take
advantage of channel contexts (if used).


-- Pozdrawiam / Best regards, Michal Kazior.

[RFC v2 1/7] mac80211: introduce channel contexts skeleton code

[Michal Kazior]

From: Kazior Michal <Michal.Kazior@tieto.com>

Channel context are the foundation for
multi-channel operation.

Channel contexts are immutable and are re-created
(or re-used if other interfaces are bound to a
certain channel) on channel switching.

This is a initial implementation and more features
will come in separate patches for easier review.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
---
 include/net/mac80211.h     |   41 +++++++++++++++
 net/mac80211/chan.c        |  123 ++++++++++++++++++++++++++++++++++++++++++++
 net/mac80211/ieee80211_i.h |   23 ++++++++
 net/mac80211/main.c        |    3 +
 4 files changed, 190 insertions(+), 0 deletions(-)

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 6914f99..0089798 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -143,6 +143,41 @@ struct ieee80211_low_level_stats {
 	unsigned int dot11RTSSuccessCount;
 };
 
+
+/**
+ * enum ieee80211_chanctx_mode - channel context configuration mode
+ *
+ * @IEEE80211_CHANCTX_SHARED: channel context may be used by
+ *	multiple interfaces
+ * @IEEE80211_CHANCTX_EXCLUSIVE: channel context can be used
+ *	only by a single interface. This can be used for example for
+ *	non-fixed channel IBSS.
+ */
+enum ieee80211_chanctx_mode {
+	IEEE80211_CHANCTX_SHARED,
+	IEEE80211_CHANCTX_EXCLUSIVE
+};
+
+/**
+ * struct ieee80211_chanctx_conf - channel context that vifs may be tuned to
+ *
+ * This is the driver-visible part. The ieee80211_chanctx
+ * that contains it is visible in mac80211 only.
+ *
+ * @channel: the channel to tune to
+ * @channel_type: the channel (HT) type
+ * @mode: the channel context mode
+ * @drv_priv: data area for driver use, will always be aligned to
+ *	sizeof(void *), size is determined in hw information.
+ */
+struct ieee80211_chanctx_conf {
+	struct ieee80211_channel *channel;
+	enum nl80211_channel_type channel_type;
+	enum ieee80211_chanctx_mode mode;
+
+	u8 drv_priv[0] __attribute__((__aligned__(sizeof(void *))));
+};
+
 /**
  * enum ieee80211_bss_change - BSS change notification flags
  *
@@ -897,6 +932,7 @@ enum ieee80211_vif_flags {
  *	at runtime, mac80211 will never touch this field
  * @hw_queue: hardware queue for each AC
  * @cab_queue: content-after-beacon (DTIM beacon really) queue, AP mode only
+ * @chanctx_conf: channel context vif is bound to, may be NULL
  * @drv_priv: data area for driver use, will always be aligned to
  *	sizeof(void *).
  */
@@ -909,6 +945,8 @@ struct ieee80211_vif {
 	u8 cab_queue;
 	u8 hw_queue[IEEE80211_NUM_ACS];
 
+	struct ieee80211_chanctx_conf *chanctx_conf;
+
 	u32 driver_flags;
 
 	/* must be last */
@@ -1268,6 +1306,8 @@ enum ieee80211_hw_flags {
  *	within &struct ieee80211_vif.
  * @sta_data_size: size (in bytes) of the drv_priv data area
  *	within &struct ieee80211_sta.
+ * @chanctx_data_size: size (in bytes) of the drv_priv data area
+ *	within &struct ieee80211_chanctx_conf.
  *
  * @max_rates: maximum number of alternate rate retry stages the hw
  *	can handle.
@@ -1312,6 +1352,7 @@ struct ieee80211_hw {
 	int channel_change_time;
 	int vif_data_size;
 	int sta_data_size;
+	int chanctx_data_size;
 	int napi_weight;
 	u16 queues;
 	u16 max_listen_interval;
diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c
index f0f87e5..f5b4a77 100644
--- a/net/mac80211/chan.c
+++ b/net/mac80211/chan.c
@@ -139,3 +139,126 @@ bool ieee80211_set_channel_type(struct ieee80211_local *local,
 
 	return result;
 }
+
+static struct ieee80211_chanctx *
+ieee80211_find_chanctx(struct ieee80211_local *local,
+		       struct ieee80211_channel *channel,
+		       enum nl80211_channel_type channel_type,
+		       enum ieee80211_chanctx_mode mode)
+{
+	struct ieee80211_chanctx *ctx;
+
+	if (mode == IEEE80211_CHANCTX_EXCLUSIVE)
+		return NULL;
+	if (WARN_ON(!channel))
+		return NULL;
+
+	list_for_each_entry(ctx, &local->chanctx_list, list) {
+		if (ctx->conf.mode == IEEE80211_CHANCTX_EXCLUSIVE)
+			continue;
+		if (ctx->conf.channel != channel)
+			continue;
+		if (ctx->conf.channel_type != channel_type)
+			continue;
+
+		return ctx;
+	}
+
+	return NULL;
+}
+
+static struct ieee80211_chanctx *
+ieee80211_new_chanctx(struct ieee80211_local *local,
+		      struct ieee80211_channel *channel,
+		      enum nl80211_channel_type channel_type,
+		      enum ieee80211_chanctx_mode mode)
+{
+	struct ieee80211_chanctx *ctx;
+
+	ctx = kzalloc(sizeof(*ctx) + local->hw.chanctx_data_size, GFP_KERNEL);
+	if (!ctx)
+		return NULL;
+
+	ctx->conf.channel = channel;
+	ctx->conf.channel_type = channel_type;
+	ctx->conf.mode = mode;
+	ctx->local = local;
+
+	list_add(&ctx->list, &local->chanctx_list);
+	INIT_LIST_HEAD(&ctx->interfaces);
+
+	return ctx;
+}
+
+static void
+ieee80211_free_chanctx(struct ieee80211_chanctx *ctx)
+{
+	BUG_ON(!list_empty(&ctx->interfaces));
+
+	list_del(&ctx->list);
+	kfree(ctx);
+}
+
+static void
+ieee80211_assign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
+			     struct ieee80211_chanctx *ctx)
+{
+	list_add(&sdata->chanctx_listitem, &ctx->interfaces);
+	sdata->vif.chanctx_conf = &ctx->conf;
+}
+
+static void
+ieee80211_unassign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
+			       struct ieee80211_chanctx *ctx)
+{
+	sdata->vif.chanctx_conf = NULL;
+	list_del(&sdata->chanctx_listitem);
+}
+
+static void
+__ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
+{
+	struct ieee80211_chanctx_conf *conf = sdata->vif.chanctx_conf;
+	struct ieee80211_chanctx *ctx =
+			container_of(conf, struct ieee80211_chanctx, conf);
+
+	if (!conf)
+		return;
+
+	ieee80211_unassign_vif_chanctx(sdata, ctx);
+	if (list_empty(&ctx->interfaces))
+		ieee80211_free_chanctx(ctx);
+}
+
+bool
+ieee80211_vif_use_channel(struct ieee80211_sub_if_data *sdata,
+			  struct ieee80211_channel *channel,
+			  enum nl80211_channel_type channel_type,
+			  enum ieee80211_chanctx_mode mode)
+{
+	struct ieee80211_local *local = sdata->local;
+	struct ieee80211_chanctx *ctx;
+
+	mutex_lock(&local->chanctx_mtx);
+	__ieee80211_vif_release_channel(sdata);
+
+	ctx = ieee80211_find_chanctx(local, channel, channel_type, mode);
+	if (!ctx)
+		ctx = ieee80211_new_chanctx(local, channel, channel_type, mode);
+	if (!ctx) {
+		mutex_unlock(&local->chanctx_mtx);
+		return false;
+	}
+
+	ieee80211_assign_vif_chanctx(sdata, ctx);
+	mutex_unlock(&local->chanctx_mtx);
+	return true;
+}
+
+void
+ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
+{
+	mutex_lock(&sdata->local->chanctx_mtx);
+	__ieee80211_vif_release_channel(sdata);
+	mutex_unlock(&sdata->local->chanctx_mtx);
+}
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index e6cbf5b..eefb932 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -645,6 +645,15 @@ enum ieee80211_sdata_state_bits {
 	SDATA_STATE_OFFCHANNEL,
 };
 
+struct ieee80211_chanctx {
+	struct list_head list;
+
+	struct ieee80211_local *local;
+	struct list_head interfaces;
+
+	struct ieee80211_chanctx_conf conf;
+};
+
 struct ieee80211_sub_if_data {
 	struct list_head list;
 
@@ -693,6 +702,8 @@ struct ieee80211_sub_if_data {
 
 	bool arp_filter_state;
 
+	struct list_head chanctx_listitem;
+
 	/*
 	 * AP this belongs to: self in AP mode and
 	 * corresponding AP in VLAN mode, NULL for
@@ -969,6 +980,10 @@ struct ieee80211_local {
 	struct ieee80211_channel *tmp_channel;
 	enum nl80211_channel_type tmp_channel_type;
 
+	/* channel contexts */
+	struct list_head chanctx_list;
+	struct mutex chanctx_mtx;
+
 	/* SNMP counters */
 	/* dot11CountersTable */
 	u32 dot11TransmittedFragmentCount;
@@ -1488,6 +1503,14 @@ bool ieee80211_set_channel_type(struct ieee80211_local *local,
 enum nl80211_channel_type
 ieee80211_ht_oper_to_channel_type(struct ieee80211_ht_operation *ht_oper);
 
+bool
+ieee80211_vif_use_channel(struct ieee80211_sub_if_data *sdata,
+			  struct ieee80211_channel *channel,
+			  enum nl80211_channel_type channel_type,
+			  enum ieee80211_chanctx_mode mode);
+void
+ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata);
+
 #ifdef CONFIG_MAC80211_NOINLINE
 #define debug_noinline noinline
 #else
diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index d81c178..735edd5 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -613,6 +613,9 @@ struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,
 	spin_lock_init(&local->filter_lock);
 	spin_lock_init(&local->queue_stop_reason_lock);
 
+	INIT_LIST_HEAD(&local->chanctx_list);
+	mutex_init(&local->chanctx_mtx);
+
 	/*
 	 * The rx_skb_queue is only accessed from tasklets,
 	 * but other SKB queues are used from within IRQ
-- 
1.7.0.4

[RFC v2 2/7] mac80211: introduce new ieee80211_ops

[Michal Kazior]

From: Kazior Michal <Michal.Kazior@tieto.com>

Introduces channel context callbacks. Channel on a
context channel is immutable. Channel type will be
changable later though, thus change_channel_type is
adveristed.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
---
 include/net/mac80211.h |   22 ++++++++++++++++++++++
 1 files changed, 22 insertions(+), 0 deletions(-)

diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 0089798..5040d6d 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -2295,6 +2295,15 @@ enum ieee80211_rate_control_changed {
  * @get_et_strings:  Ethtool API to get a set of strings to describe stats
  *	and perhaps other supported types of ethtool data-sets.
  *
+ * @add_chanctx: Notifies device driver about new channel context creation.
+ * @remove_chanctx: Notifies device driver about channel context destruction.
+ * @change_chantype: Notifies device driver about channel context channel_type
+ *	change which may happen when combining different vifs on a same channel
+ *	with different HTs.
+ * @assign_vif_chanctx: Notifies device driver about channel context being bound
+ *	to vif. Possible use is for hw queue remapping.
+ * @unassign_vif_chanctx: Notifies device driver about channel context being
+ *	unbound from vif.
  */
 struct ieee80211_ops {
 	void (*tx)(struct ieee80211_hw *hw, struct sk_buff *skb);
@@ -2434,6 +2443,19 @@ struct ieee80211_ops {
 	void	(*get_et_strings)(struct ieee80211_hw *hw,
 				  struct ieee80211_vif *vif,
 				  u32 sset, u8 *data);
+
+	void (*add_chanctx)(struct ieee80211_hw *hw,
+			    struct ieee80211_chanctx_conf *ctx);
+	void (*remove_chanctx)(struct ieee80211_hw *hw,
+			       struct ieee80211_chanctx_conf *ctx);
+	void (*change_chantype)(struct ieee80211_hw *hw,
+				struct ieee80211_chanctx_conf *ctx);
+	void (*assign_vif_chanctx)(struct ieee80211_hw *hw,
+				   struct ieee80211_vif *vif,
+				   struct ieee80211_chanctx_conf *ctx);
+	void (*unassign_vif_chanctx)(struct ieee80211_hw *hw,
+				     struct ieee80211_vif *vif,
+				     struct ieee80211_chanctx_conf *ctx);
 };
 
 /**
-- 
1.7.0.4

[RFC v2 3/7] mac80211: add drv_* wrappers for channel contexts

[Michal Kazior]

From: Kazior Michal <Michal.Kazior@tieto.com>

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
---
 net/mac80211/driver-ops.h |   51 +++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 51 insertions(+), 0 deletions(-)

diff --git a/net/mac80211/driver-ops.h b/net/mac80211/driver-ops.h
index 6d33a0c..e79f06d 100644
--- a/net/mac80211/driver-ops.h
+++ b/net/mac80211/driver-ops.h
@@ -845,4 +845,55 @@ drv_allow_buffered_frames(struct ieee80211_local *local,
 						  more_data);
 	trace_drv_return_void(local);
 }
+
+static inline void
+drv_add_chanctx(struct ieee80211_local *local,
+		struct ieee80211_chanctx *ctx)
+{
+	if (local->ops->add_chanctx)
+		local->ops->add_chanctx(&local->hw, &ctx->conf);
+}
+
+static inline void
+drv_remove_chanctx(struct ieee80211_local *local,
+		   struct ieee80211_chanctx *ctx)
+{
+	if (local->ops->remove_chanctx)
+		local->ops->remove_chanctx(&local->hw, &ctx->conf);
+}
+
+static inline void
+drv_change_chantype(struct ieee80211_local *local,
+		    struct ieee80211_chanctx *ctx)
+{
+	if (local->ops->change_chantype)
+		local->ops->change_chantype(&local->hw, &ctx->conf);
+}
+
+static inline void
+drv_assign_vif_chanctx(struct ieee80211_local *local,
+		       struct ieee80211_sub_if_data *sdata,
+		       struct ieee80211_chanctx *ctx)
+{
+	check_sdata_in_driver(sdata);
+
+	if (local->ops->assign_vif_chanctx)
+		local->ops->assign_vif_chanctx(&local->hw,
+					       &sdata->vif,
+					       &ctx->conf);
+}
+
+static inline void
+drv_unassign_vif_chanctx(struct ieee80211_local *local,
+			 struct ieee80211_sub_if_data *sdata,
+			 struct ieee80211_chanctx *ctx)
+{
+	check_sdata_in_driver(sdata);
+
+	if (local->ops->unassign_vif_chanctx)
+		local->ops->unassign_vif_chanctx(&local->hw,
+						 &sdata->vif,
+						 &ctx->conf);
+}
+
 #endif /* __MAC80211_DRIVER_OPS */
-- 
1.7.0.4

[RFC v2 4/7] mac80211: add chanctx tracing

[Michal Kazior]

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
---
 net/mac80211/driver-ops.h   |   10 +++++
 net/mac80211/driver-trace.h |   88 +++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 98 insertions(+), 0 deletions(-)

diff --git a/net/mac80211/driver-ops.h b/net/mac80211/driver-ops.h
index e79f06d..dde9f33 100644
--- a/net/mac80211/driver-ops.h
+++ b/net/mac80211/driver-ops.h
@@ -850,24 +850,30 @@ static inline void
 drv_add_chanctx(struct ieee80211_local *local,
 		struct ieee80211_chanctx *ctx)
 {
+	trace_drv_add_chanctx(local, ctx);
 	if (local->ops->add_chanctx)
 		local->ops->add_chanctx(&local->hw, &ctx->conf);
+	trace_drv_return_void(local);
 }
 
 static inline void
 drv_remove_chanctx(struct ieee80211_local *local,
 		   struct ieee80211_chanctx *ctx)
 {
+	trace_drv_remove_chanctx(local, ctx);
 	if (local->ops->remove_chanctx)
 		local->ops->remove_chanctx(&local->hw, &ctx->conf);
+	trace_drv_return_void(local);
 }
 
 static inline void
 drv_change_chantype(struct ieee80211_local *local,
 		    struct ieee80211_chanctx *ctx)
 {
+	trace_drv_change_chantype(local, ctx);
 	if (local->ops->change_chantype)
 		local->ops->change_chantype(&local->hw, &ctx->conf);
+	trace_drv_return_void(local);
 }
 
 static inline void
@@ -877,10 +883,12 @@ drv_assign_vif_chanctx(struct ieee80211_local *local,
 {
 	check_sdata_in_driver(sdata);
 
+	trace_drv_assign_vif_chanctx(local, sdata, ctx);
 	if (local->ops->assign_vif_chanctx)
 		local->ops->assign_vif_chanctx(&local->hw,
 					       &sdata->vif,
 					       &ctx->conf);
+	trace_drv_return_void(local);
 }
 
 static inline void
@@ -890,10 +898,12 @@ drv_unassign_vif_chanctx(struct ieee80211_local *local,
 {
 	check_sdata_in_driver(sdata);
 
+	trace_drv_unassign_vif_chanctx(local, sdata, ctx);
 	if (local->ops->unassign_vif_chanctx)
 		local->ops->unassign_vif_chanctx(&local->hw,
 						 &sdata->vif,
 						 &ctx->conf);
+	trace_drv_return_void(local);
 }
 
 #endif /* __MAC80211_DRIVER_OPS */
diff --git a/net/mac80211/driver-trace.h b/net/mac80211/driver-trace.h
index 6de00b2..16b0e43 100644
--- a/net/mac80211/driver-trace.h
+++ b/net/mac80211/driver-trace.h
@@ -1606,6 +1606,94 @@ TRACE_EVENT(stop_queue,
 		LOCAL_PR_ARG, __entry->queue, __entry->reason
 	)
 );
+
+DECLARE_EVENT_CLASS(local_chanctx,
+	TP_PROTO(struct ieee80211_local *local,
+		 struct ieee80211_chanctx *ctx),
+
+	TP_ARGS(local, ctx),
+
+	TP_STRUCT__entry(
+		LOCAL_ENTRY
+		__field(void *, ctx)
+		__field(int, freq)
+		__field(int, chantype)
+	),
+
+	TP_fast_assign(
+		LOCAL_ASSIGN;
+		__entry->ctx = ctx;
+		__entry->freq = ctx->conf.channel->center_freq;
+		__entry->chantype = ctx->conf.channel_type;
+	),
+
+	TP_printk(
+		LOCAL_PR_FMT " ctx:%p freq:%dMhz chantype:%d",
+		LOCAL_PR_ARG, __entry->ctx, __entry->freq, __entry->chantype
+	)
+);
+
+DEFINE_EVENT(local_chanctx, drv_add_chanctx,
+	TP_PROTO(struct ieee80211_local *local,
+		 struct ieee80211_chanctx *ctx),
+	TP_ARGS(local, ctx)
+);
+
+DEFINE_EVENT(local_chanctx, drv_remove_chanctx,
+	TP_PROTO(struct ieee80211_local *local,
+		 struct ieee80211_chanctx *ctx),
+	TP_ARGS(local, ctx)
+);
+
+DEFINE_EVENT(local_chanctx, drv_change_chantype,
+	TP_PROTO(struct ieee80211_local *local,
+		 struct ieee80211_chanctx *ctx),
+	TP_ARGS(local, ctx)
+);
+
+DECLARE_EVENT_CLASS(local_sdata_chanctx,
+	TP_PROTO(struct ieee80211_local *local,
+		 struct ieee80211_sub_if_data *sdata,
+		 struct ieee80211_chanctx *ctx),
+
+	TP_ARGS(local, sdata, ctx),
+
+	TP_STRUCT__entry(
+		LOCAL_ENTRY
+		VIF_ENTRY
+		__field(void *, ctx)
+		__field(int, freq)
+		__field(int, chantype)
+	),
+
+	TP_fast_assign(
+		LOCAL_ASSIGN;
+		VIF_ASSIGN;
+		__entry->ctx = ctx;
+		__entry->freq = ctx->conf.channel->center_freq;
+		__entry->chantype = ctx->conf.channel_type;
+	),
+
+	TP_printk(
+		LOCAL_PR_FMT VIF_PR_FMT " ctx:%p freq:%dMhz chantype:%d",
+		LOCAL_PR_ARG, VIF_PR_ARG,
+		__entry->ctx, __entry->freq, __entry->chantype
+	)
+);
+
+DEFINE_EVENT(local_sdata_chanctx, drv_assign_vif_chanctx,
+	TP_PROTO(struct ieee80211_local *local,
+		 struct ieee80211_sub_if_data *sdata,
+		 struct ieee80211_chanctx *ctx),
+	TP_ARGS(local, sdata, ctx)
+);
+
+DEFINE_EVENT(local_sdata_chanctx, drv_unassign_vif_chanctx,
+	TP_PROTO(struct ieee80211_local *local,
+		 struct ieee80211_sub_if_data *sdata,
+		 struct ieee80211_chanctx *ctx),
+	TP_ARGS(local, sdata, ctx)
+);
 #endif /* !__MAC80211_DRIVER_TRACE || TRACE_HEADER_MULTI_READ */
 
 #undef TRACE_INCLUDE_PATH
-- 
1.7.0.4

[RFC v2 5/7] mac80211: use channel context notifications

[Michal Kazior]

From: Kazior Michal <Michal.Kazior@tieto.com>

Channel context pointer will be accessiable on
both assign and unassign events.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
---
 net/mac80211/chan.c |    9 +++++++++
 1 files changed, 9 insertions(+), 0 deletions(-)

diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c
index f5b4a77..20483a0 100644
--- a/net/mac80211/chan.c
+++ b/net/mac80211/chan.c
@@ -5,6 +5,7 @@
 #include <linux/nl80211.h>
 #include <net/cfg80211.h>
 #include "ieee80211_i.h"
+#include "driver-ops.h"
 
 static enum ieee80211_chan_mode
 __ieee80211_get_channel_mode(struct ieee80211_local *local,
@@ -187,6 +188,8 @@ ieee80211_new_chanctx(struct ieee80211_local *local,
 	list_add(&ctx->list, &local->chanctx_list);
 	INIT_LIST_HEAD(&ctx->interfaces);
 
+	drv_add_chanctx(local, ctx);
+
 	return ctx;
 }
 
@@ -195,6 +198,8 @@ ieee80211_free_chanctx(struct ieee80211_chanctx *ctx)
 {
 	BUG_ON(!list_empty(&ctx->interfaces));
 
+	drv_remove_chanctx(ctx->local, ctx);
+
 	list_del(&ctx->list);
 	kfree(ctx);
 }
@@ -205,12 +210,16 @@ ieee80211_assign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
 {
 	list_add(&sdata->chanctx_listitem, &ctx->interfaces);
 	sdata->vif.chanctx_conf = &ctx->conf;
+
+	drv_assign_vif_chanctx(sdata->local, sdata, ctx);
 }
 
 static void
 ieee80211_unassign_vif_chanctx(struct ieee80211_sub_if_data *sdata,
 			       struct ieee80211_chanctx *ctx)
 {
+	drv_unassign_vif_chanctx(sdata->local, sdata, ctx);
+
 	sdata->vif.chanctx_conf = NULL;
 	list_del(&sdata->chanctx_listitem);
 }
-- 
1.7.0.4

[RFC v2 6/7] mac80211: refactor set_channel_type

[Michal Kazior]

From: Kazior Michal <Michal.Kazior@tieto.com>

Split functionality for further reuse.

Will prevent code duplication when channel context
channel_type merging is introduced.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
---
 net/mac80211/chan.c |   57 ++++++++++++++++++++++++++++++++++-----------------
 1 files changed, 38 insertions(+), 19 deletions(-)

diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c
index 20483a0..63b7cb7 100644
--- a/net/mac80211/chan.c
+++ b/net/mac80211/chan.c
@@ -69,16 +69,14 @@ ieee80211_get_channel_mode(struct ieee80211_local *local,
 	return mode;
 }
 
-bool ieee80211_set_channel_type(struct ieee80211_local *local,
-				struct ieee80211_sub_if_data *sdata,
-				enum nl80211_channel_type chantype)
+static enum nl80211_channel_type
+ieee80211_get_superchan(struct ieee80211_local *local,
+			struct ieee80211_sub_if_data *sdata)
 {
-	struct ieee80211_sub_if_data *tmp;
 	enum nl80211_channel_type superchan = NL80211_CHAN_NO_HT;
-	bool result;
+	struct ieee80211_sub_if_data *tmp;
 
 	mutex_lock(&local->iflist_mtx);
-
 	list_for_each_entry(tmp, &local->interfaces, list) {
 		if (tmp == sdata)
 			continue;
@@ -104,41 +102,62 @@ bool ieee80211_set_channel_type(struct ieee80211_local *local,
 			break;
 		}
 	}
+	mutex_unlock(&local->iflist_mtx);
+
+	return superchan;
+}
 
-	switch (superchan) {
+static bool
+ieee80211_channel_types_are_compatible(enum nl80211_channel_type chantype1,
+				       enum nl80211_channel_type chantype2,
+				       enum nl80211_channel_type *compat)
+{
+	switch (chantype1) {
 	case NL80211_CHAN_NO_HT:
 	case NL80211_CHAN_HT20:
 		/*
 		 * allow any change that doesn't go to no-HT
 		 * (if it already is no-HT no change is needed)
 		 */
-		if (chantype == NL80211_CHAN_NO_HT)
+		if (chantype2 == NL80211_CHAN_NO_HT)
 			break;
-		superchan = chantype;
+		*compat = chantype2;
 		break;
 	case NL80211_CHAN_HT40PLUS:
 	case NL80211_CHAN_HT40MINUS:
+		*compat = chantype1;
 		/* allow smaller bandwidth and same */
-		if (chantype == NL80211_CHAN_NO_HT)
+		if (chantype2 == NL80211_CHAN_NO_HT)
 			break;
-		if (chantype == NL80211_CHAN_HT20)
+		if (chantype2 == NL80211_CHAN_HT20)
 			break;
-		if (superchan == chantype)
+		if (chantype2 == chantype1)
 			break;
-		result = false;
-		goto out;
+		return false;
 	}
 
-	local->_oper_channel_type = superchan;
+	return true;
+}
+
+bool ieee80211_set_channel_type(struct ieee80211_local *local,
+				struct ieee80211_sub_if_data *sdata,
+				enum nl80211_channel_type chantype)
+{
+	enum nl80211_channel_type superchan;
+	enum nl80211_channel_type compatchan = NL80211_CHAN_NO_HT;
+
+	superchan = ieee80211_get_superchan(local, sdata);
+	if (!ieee80211_channel_types_are_compatible(superchan, chantype,
+						    &compatchan))
+		return false;
+
+	local->_oper_channel_type = compatchan;
 
 	if (sdata)
 		sdata->vif.bss_conf.channel_type = chantype;
 
-	result = true;
- out:
-	mutex_unlock(&local->iflist_mtx);
+	return true;
 
-	return result;
 }
 
 static struct ieee80211_chanctx *
-- 
1.7.0.4

[RFC v2 7/7] mac80211: reuse channels for channel context

[Michal Kazior]

From: Kazior Michal <Michal.Kazior@tieto.com>

Reuse channels with compatible channel types. Some
channel types are compatible and can be used
concurrently.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
---
 net/mac80211/chan.c |   11 +++++++++++
 1 files changed, 11 insertions(+), 0 deletions(-)

diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c
index 63b7cb7..97be454 100644
--- a/net/mac80211/chan.c
+++ b/net/mac80211/chan.c
@@ -167,6 +167,7 @@ ieee80211_find_chanctx(struct ieee80211_local *local,
 		       enum ieee80211_chanctx_mode mode)
 {
 	struct ieee80211_chanctx *ctx;
+	enum nl80211_channel_type compat_type;
 
 	if (mode == IEEE80211_CHANCTX_EXCLUSIVE)
 		return NULL;
@@ -174,12 +175,22 @@ ieee80211_find_chanctx(struct ieee80211_local *local,
 		return NULL;
 
 	list_for_each_entry(ctx, &local->chanctx_list, list) {
+		compat_type = ctx->conf.channel_type;
+
 		if (ctx->conf.mode == IEEE80211_CHANCTX_EXCLUSIVE)
 			continue;
 		if (ctx->conf.channel != channel)
 			continue;
 		if (ctx->conf.channel_type != channel_type)
 			continue;
+		if (!ieee80211_channel_types_are_compatible(ctx->conf.channel_type,
+							    channel_type,
+							    &compat_type))
+			continue;
+		if (ctx->conf.channel_type != compat_type) {
+			ctx->conf.channel_type = compat_type;
+			drv_change_chantype(local, ctx);
+		}
 
 		return ctx;
 	}
-- 
1.7.0.4

Re: [RFC v2] initial channel context implementation

[Johannes Berg]

On Thu, 2012-06-21 at 14:03 +0200, Michal Kazior wrote:
> Hi,
> 
> Here's my respin of channel contexts patches. Thanks for the
> review on the previous version.

Looks pretty good to me, I'll follow up on the patches with some minor
comments.

> Changes in short:
> 
>  * renamed to chanctx (to avoid very_long_structure_names)
>  * pub/priv part added (and drv_priv)
>  * new mutex added
>  * channel contexts are a linked list
>  * tracing added
> 
> Next step would be to refactor mac80211 codepaths to take
> advantage of channel contexts (if used).

Sounds about right :)

johannes

Re: [RFC v2 1/7] mac80211: introduce channel contexts skeleton code

[Johannes Berg]

On Thu, 2012-06-21 at 14:03 +0200, Michal Kazior wrote:

> +++ b/include/net/mac80211.h
> @@ -143,6 +143,41 @@ struct ieee80211_low_level_stats {
>  	unsigned int dot11RTSSuccessCount;
>  };
>  
> +
> +/**
> + * enum ieee80211_chanctx_mode - channel context configuration mode
> + *
> + * @IEEE80211_CHANCTX_SHARED: channel context may be used by
> + *	multiple interfaces
> + * @IEEE80211_CHANCTX_EXCLUSIVE: channel context can be used
> + *	only by a single interface. This can be used for example for
> + *	non-fixed channel IBSS.
> + */
> +enum ieee80211_chanctx_mode {
> +	IEEE80211_CHANCTX_SHARED,
> +	IEEE80211_CHANCTX_EXCLUSIVE
> +};

Does the driver ever care about this? It seems mostly internal to
determine what's going on?


> + * @chanctx_conf: channel context vif is bound to, may be NULL

Maybe say "will be %NULL before the interface is assigned to a channel
context" or so?

> +	INIT_LIST_HEAD(&ctx->interfaces);

Is there really a need for this list? It seems only moderately less
efficient to iterate all interfaces and filter by channel context, and
that's probably easier to maintain?

> +static void
> +__ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
> +{
> +	struct ieee80211_chanctx_conf *conf = sdata->vif.chanctx_conf;
> +	struct ieee80211_chanctx *ctx =
> +			container_of(conf, struct ieee80211_chanctx, conf);
> +
> +	if (!conf)
> +		return;
> +
> +	ieee80211_unassign_vif_chanctx(sdata, ctx);
> +	if (list_empty(&ctx->interfaces))
> +		ieee80211_free_chanctx(ctx);
> +}

Ah, ok. So I guess there's a good use for the list at least here.

johannes

Re: [RFC v2 7/7] mac80211: reuse channels for channel context

[Johannes Berg]

On Thu, 2012-06-21 at 14:03 +0200, Michal Kazior wrote:

> +		if (!ieee80211_channel_types_are_compatible(ctx->conf.channel_type,
> +							    channel_type,
> +							    &compat_type))
> +			continue;
> +		if (ctx->conf.channel_type != compat_type) {
> +			ctx->conf.channel_type = compat_type;
> +			drv_change_chantype(local, ctx);
> +		}

Maybe somehow there's a need to also keep track of the desired channel
type per vif so it can be recalculated when a vif is removed, not just
when one is added?

johannes

Re: [RFC v2 1/7] mac80211: introduce channel contexts skeleton code

[Michal Kazior]

Johannes Berg wrote:
> On Thu, 2012-06-21 at 14:03 +0200, Michal Kazior wrote:
>
>> +++ b/include/net/mac80211.h
>> @@ -143,6 +143,41 @@ struct ieee80211_low_level_stats {
>>   	unsigned int dot11RTSSuccessCount;
>>   };
>>
>> +
>> +/**
>> + * enum ieee80211_chanctx_mode - channel context configuration mode
>> + *
>> + * @IEEE80211_CHANCTX_SHARED: channel context may be used by
>> + *	multiple interfaces
>> + * @IEEE80211_CHANCTX_EXCLUSIVE: channel context can be used
>> + *	only by a single interface. This can be used for example for
>> + *	non-fixed channel IBSS.
>> + */
>> +enum ieee80211_chanctx_mode {
>> +	IEEE80211_CHANCTX_SHARED,
>> +	IEEE80211_CHANCTX_EXCLUSIVE
>> +};
>
> Does the driver ever care about this? It seems mostly internal to
> determine what's going on?

Why did I put it there I wonder.


>> + * @chanctx_conf: channel context vif is bound to, may be NULL
>
> Maybe say "will be %NULL before the interface is assigned to a channel
> context" or so?
>
>> +	INIT_LIST_HEAD(&ctx->interfaces);
>
> Is there really a need for this list? It seems only moderately less
> efficient to iterate all interfaces and filter by channel context, and
> that's probably easier to maintain?
>
>> +static void
>> +__ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)
>> +{
>> +	struct ieee80211_chanctx_conf *conf = sdata->vif.chanctx_conf;
>> +	struct ieee80211_chanctx *ctx =
>> +			container_of(conf, struct ieee80211_chanctx, conf);
>> +
>> +	if (!conf)
>> +		return;
>> +
>> +	ieee80211_unassign_vif_chanctx(sdata, ctx);
>> +	if (list_empty(&ctx->interfaces))
>> +		ieee80211_free_chanctx(ctx);
>> +}
>
> Ah, ok. So I guess there's a good use for the list at least here.

Actually you're right. I'll make it a simple refcount. No need to do 
fancy lists.


-- 
Pozdrawiam / Best regards, Michal Kazior.

Re: [RFC v2 7/7] mac80211: reuse channels for channel context

[Michal Kazior]

Johannes Berg wrote:
> On Thu, 2012-06-21 at 14:03 +0200, Michal Kazior wrote:
>
>> +		if (!ieee80211_channel_types_are_compatible(ctx->conf.channel_type,
>> +							    channel_type,
>> +							&compat_type))
>> +			continue;
>> +		if (ctx->conf.channel_type != compat_type) {
>> +			ctx->conf.channel_type = compat_type;
>> +			drv_change_chantype(local, ctx);
>> +		}
>
> Maybe somehow there's a need to also keep track of the desired channel
> type per vif so it can be recalculated when a vif is removed, not just
> when one is added?

Sounds good.


-- 
Pozdrawiam / Best regards, Michal Kazior.