Commit d01a1e65 authored by Michal Kazior's avatar Michal Kazior Committed by Johannes Berg
Browse files

mac80211: introduce channel context skeleton code 



Channel context are the foundation for multi-channel
operation. They are are immutable and are re-created
(or re-used if other interfaces are bound to a certain
channel and a compatible channel type) on channel
switching.

This is an initial implementation and more features
will come in separate patches.

Signed-off-by: default avatarMichal Kazior <michal.kazior@tieto.com>
[some changes including RCU protection]
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent ddffeb8c

include/net/mac80211.h

+36 −0
Original line number Diff line number Diff line
@@ -143,6 +143,32 @@ struct ieee80211_low_level_stats { 
	unsigned int dot11RTSSuccessCount;

};



/**

 * enum ieee80211_chanctx_change - change flag for channel context

 * @IEEE80211_CHANCTX_CHANGE_CHANNEL_TYPE: The channel type was changed

 */

enum ieee80211_chanctx_change {

	IEEE80211_CHANCTX_CHANGE_CHANNEL_TYPE	= BIT(0),

};



/**

 * 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

 * @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;



	u8 drv_priv[0] __attribute__((__aligned__(sizeof(void *))));

};



/**

 * enum ieee80211_bss_change - BSS change notification flags

 *
@@ -931,6 +957,11 @@ 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: The channel context this interface is assigned to, or %NULL

 *	when it is not assigned. This pointer is RCU-protected due to the TX

 *	path needing to access it; even though the netdev carrier will always

 *	be off when it is %NULL there can still be races and packets could be

 *	processed after it switches back to %NULL.

 * @drv_priv: data area for driver use, will always be aligned to

 *	sizeof(void *).

 */
@@ -943,6 +974,8 @@ struct ieee80211_vif { 
	u8 cab_queue;

	u8 hw_queue[IEEE80211_NUM_ACS];



	struct ieee80211_chanctx_conf __rcu *chanctx_conf;



	u32 driver_flags;



	/* must be last */
@@ -1325,6 +1358,8 @@ 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.
@@ -1369,6 +1404,7 @@ 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;

net/mac80211/chan.c

+147 −0
Original line number Diff line number Diff line
@@ -168,3 +168,150 @@ bool ieee80211_set_channel_type(struct ieee80211_local *local, 
	return true;



}



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;



	lockdep_assert_held(&local->chanctx_mtx);



	if (mode == IEEE80211_CHANCTX_EXCLUSIVE)

		return NULL;

	if (WARN_ON(!channel))

		return NULL;



	list_for_each_entry(ctx, &local->chanctx_list, list) {

		if (ctx->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;



	lockdep_assert_held(&local->chanctx_mtx);



	ctx = kzalloc(sizeof(*ctx) + local->hw.chanctx_data_size, GFP_KERNEL);

	if (!ctx)

		return ERR_PTR(-ENOMEM);



	ctx->conf.channel = channel;

	ctx->conf.channel_type = channel_type;

	ctx->mode = mode;



	list_add(&ctx->list, &local->chanctx_list);



	return ctx;

}



static void ieee80211_free_chanctx(struct ieee80211_local *local,

				   struct ieee80211_chanctx *ctx)

{

	lockdep_assert_held(&local->chanctx_mtx);



	WARN_ON_ONCE(ctx->refcount != 0);



	list_del(&ctx->list);

	kfree_rcu(ctx, rcu_head);

}



static int ieee80211_assign_vif_chanctx(struct ieee80211_sub_if_data *sdata,

					struct ieee80211_chanctx *ctx)

{

	struct ieee80211_local *local __maybe_unused = sdata->local;



	lockdep_assert_held(&local->chanctx_mtx);



	rcu_assign_pointer(sdata->vif.chanctx_conf, &ctx->conf);

	ctx->refcount++;



	return 0;

}



static void ieee80211_unassign_vif_chanctx(struct ieee80211_sub_if_data *sdata,

					   struct ieee80211_chanctx *ctx)

{

	struct ieee80211_local *local __maybe_unused = sdata->local;



	lockdep_assert_held(&local->chanctx_mtx);



	ctx->refcount--;

	rcu_assign_pointer(sdata->vif.chanctx_conf, NULL);

}



static void __ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata)

{

	struct ieee80211_local *local = sdata->local;

	struct ieee80211_chanctx_conf *conf;

	struct ieee80211_chanctx *ctx;



	lockdep_assert_held(&local->chanctx_mtx);



	conf = rcu_dereference_protected(sdata->vif.chanctx_conf,

					 lockdep_is_held(&local->chanctx_mtx));

	if (!conf)

		return;



	ctx = container_of(conf, struct ieee80211_chanctx, conf);



	ieee80211_unassign_vif_chanctx(sdata, ctx);

	if (ctx->refcount == 0)

		ieee80211_free_chanctx(local, ctx);

}



int 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;

	int ret;



	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 (IS_ERR(ctx)) {

		ret = PTR_ERR(ctx);

		goto out;

	}



	ret = ieee80211_assign_vif_chanctx(sdata, ctx);

	if (ret) {

		/* if assign fails refcount stays the same */

		if (ctx->refcount == 0)

			ieee80211_free_chanctx(local, ctx);

		goto out;

	}



 out:

	mutex_unlock(&local->chanctx_mtx);

	return ret;

}



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);

}

net/mac80211/ieee80211_i.h

+35 −0
Original line number Diff line number Diff line
@@ -658,6 +658,30 @@ enum ieee80211_sdata_state_bits { 
	SDATA_STATE_OFFCHANNEL,

};



/**

 * 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 {

	struct list_head list;

	struct rcu_head rcu_head;



	enum ieee80211_chanctx_mode mode;

	int refcount;



	struct ieee80211_chanctx_conf conf;

};



struct ieee80211_sub_if_data {

	struct list_head list;
@@ -987,6 +1011,10 @@ 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;
@@ -1510,6 +1538,13 @@ 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);



int __must_check

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

net/mac80211/main.c

+3 −0
Original line number Diff line number Diff line
@@ -626,6 +626,9 @@ 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

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