From d01a1e658606a0a69100f49c2ef09aacaf74d3e7 Mon Sep 17 00:00:00 2001 From: Michal Kazior Date: Tue, 26 Jun 2012 14:37:16 +0200 Subject: 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 --- net/mac80211/chan.c | 147 ++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 147 insertions(+) (limited to 'net/mac80211/chan.c') 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); +} -- cgit 1.4.1