From: Michal Kazior <michal.kazior@xxxxxxxxx>
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: Michal Kazior <michal.kazior@xxxxxxxxx>
[some changes including RCU protection]
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
---
include/net/mac80211.h | 36 ++++++++++++
net/mac80211/chan.c | 136 ++++++++++++++++++++++++++++++++++++++++++++
net/mac80211/ieee80211_i.h | 34 +++++++++++
net/mac80211/main.c | 3 +
4 files changed, 209 insertions(+)
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 82558c8..ab1b5ba 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -144,6 +144,32 @@ struct ieee80211_low_level_stats {
};
/**
+ * 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
*
* These flags are used with the bss_info_changed() callback
@@ -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;
diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c
index 0bfc914..9674968 100644
--- a/net/mac80211/chan.c
+++ b/net/mac80211/chan.c
@@ -168,3 +168,139 @@ 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 NULL;
+
+ 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 void 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++;
+}
+
+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);
+}
+
+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 8c80455..6199a25 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -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 +1538,12 @@ 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 c80c449..9be3ef1 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -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
--
1.7.10.4
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