From d01a1e658606a0a69100f49c2ef09aacaf74d3e7 Mon Sep 17 00:00:00 2001 From: Michal Kazior Date: Tue, 26 Jun 2012 14:37:16 +0200 Subject: [PATCH] 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: Michal Kazior [some changes including RCU protection] Signed-off-by: Johannes Berg --- include/net/mac80211.h | 36 +++++++++ net/mac80211/chan.c | 147 +++++++++++++++++++++++++++++++++++++ net/mac80211/ieee80211_i.h | 35 +++++++++ net/mac80211/main.c | 3 + 4 files changed, 221 insertions(+) diff --git a/include/net/mac80211.h b/include/net/mac80211.h index 82558c8decf8..ab1b5bafb568 100644 --- a/include/net/mac80211.h +++ b/include/net/mac80211.h @@ -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; diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c index 0bfc914ddd15..4ae94860a161 100644 --- a/net/mac80211/chan.c +++ b/net/mac80211/chan.c @@ -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); +} diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index 8c804550465b..9a058e58d53e 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 +1538,13 @@ 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 diff --git a/net/mac80211/main.c b/net/mac80211/main.c index c80c4490351c..9be3ef1d2e86 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 -- 2.30.2