Return-path: Received: from emh04.mail.saunalahti.fi ([62.142.5.110]:35999 "EHLO emh04.mail.saunalahti.fi" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754855AbaCELLu (ORCPT ); Wed, 5 Mar 2014 06:11:50 -0500 From: Luca Coelho To: linux-wireless@vger.kernel.org Cc: johannes@sipsolutions.net, michal.kazior@tieto.com, sw@simonwunderlich.de, andrei.otcheretianski@intel.com Subject: [PATCH v5 2/3] mac80211: implement chanctx reservation Date: Wed, 5 Mar 2014 13:11:43 +0200 Message-Id: <1394017904-4012-3-git-send-email-luca@coelho.fi> (sfid-20140305_121157_481462_FD764783) In-Reply-To: <1394017904-4012-1-git-send-email-luca@coelho.fi> References: <1394017904-4012-1-git-send-email-luca@coelho.fi> Sender: linux-wireless-owner@vger.kernel.org List-ID: From: Luciano Coelho In order to support channel switch with multiple vifs and multiple contexts, we implement a concept of channel context reservation. This allows us to reserve a channel context to be used later. The reservation functionality is not tied directly to channel switch and may be used in other situations (eg. reserving a channel context during IBSS join). We first check if an existing compatible context exists and if it does, we reserve it. If there is no compatible context we create a new one and reserve it. Signed-off-by: Luciano Coelho --- In RFC v2: * reformulated the patch to make channel reservation generic and not only for channel switch, as we may find other uses for it in the future; * added ieee80211_vif_unreserve_chanctx(); * removed reservation of the current chanctx from this patch; * added a stop_queue_reason for chanctx reservation; * added a few TODOs according to Michal's comments to be handled in future patch series; * set sdata->csa_chandef to the received chandef in all cases (it was only happening in the alone-in-the-vif case; In v3: * removed stray empty line; * reworded the commit message; * added reserved_chandef; * added comment about reserved_chanctx and reserved_chandef protection; * wake the queues if ieee80211_assign_vif_chanctx() fails; In v4: * add chanctx mode parameter to ieee80211_vif_reserve_chanctx(); * compare the vif's previous BSS width with the reserved new width instead of comparing it to the chanctx's combined width; --- net/mac80211/chan.c | 127 +++++++++++++++++++++++++++++++++++++++++++++ net/mac80211/ieee80211_i.h | 14 +++++ 2 files changed, 141 insertions(+) diff --git a/net/mac80211/chan.c b/net/mac80211/chan.c index a27c6ec..9dfdba5 100644 --- a/net/mac80211/chan.c +++ b/net/mac80211/chan.c @@ -419,6 +419,9 @@ static void __ieee80211_vif_release_channel(struct ieee80211_sub_if_data *sdata) ctx = container_of(conf, struct ieee80211_chanctx, conf); + if (sdata->reserved_chanctx) + ieee80211_vif_unreserve_chanctx(sdata); + ieee80211_unassign_vif_chanctx(sdata, ctx); if (ctx->refcount == 0) ieee80211_free_chanctx(local, ctx); @@ -611,6 +614,130 @@ int ieee80211_vif_change_channel(struct ieee80211_sub_if_data *sdata, return ret; } +int ieee80211_vif_unreserve_chanctx(struct ieee80211_sub_if_data *sdata) +{ + lockdep_assert_held(&sdata->local->chanctx_mtx); + + if (WARN_ON(!sdata->reserved_chanctx)) + return -EINVAL; + + if (--sdata->reserved_chanctx->refcount == 0) + ieee80211_free_chanctx(sdata->local, sdata->reserved_chanctx); + + sdata->reserved_chanctx = NULL; + + return 0; +} + +int ieee80211_vif_reserve_chanctx(struct ieee80211_sub_if_data *sdata, + const struct cfg80211_chan_def *chandef, + enum ieee80211_chanctx_mode mode) +{ + struct ieee80211_local *local = sdata->local; + struct ieee80211_chanctx_conf *conf; + struct ieee80211_chanctx *new_ctx, *curr_ctx; + int ret = 0; + + mutex_lock(&local->chanctx_mtx); + + conf = rcu_dereference_protected(sdata->vif.chanctx_conf, + lockdep_is_held(&local->chanctx_mtx)); + if (!conf) { + ret = -EINVAL; + goto out; + } + + curr_ctx = container_of(conf, struct ieee80211_chanctx, conf); + + /* try to find another context with the chandef we want */ + new_ctx = ieee80211_find_chanctx(local, chandef, mode); + if (!new_ctx) { + /* create a new context */ + new_ctx = ieee80211_new_chanctx(local, chandef, mode); + if (IS_ERR(new_ctx)) { + ret = PTR_ERR(new_ctx); + goto out; + } + } + + /* reserve the new or existing context */ + sdata->reserved_chanctx = new_ctx; + new_ctx->refcount++; + + sdata->reserved_chandef = *chandef; +out: + mutex_unlock(&local->chanctx_mtx); + return ret; +} + +int ieee80211_vif_use_reserved_context(struct ieee80211_sub_if_data *sdata, + u32 *changed) +{ + struct ieee80211_local *local = sdata->local; + struct ieee80211_chanctx *ctx; + struct ieee80211_chanctx *old_ctx; + struct ieee80211_chanctx_conf *conf; + int ret, local_changed = *changed; + + /* TODO: need to recheck if the chandef is usable etc.? */ + + lockdep_assert_held(&local->mtx); + + mutex_lock(&local->chanctx_mtx); + + ctx = sdata->reserved_chanctx; + if (WARN_ON(!ctx)) { + ret = -EINVAL; + goto out; + } + + conf = rcu_dereference_protected(sdata->vif.chanctx_conf, + lockdep_is_held(&local->chanctx_mtx)); + if (!conf) { + ret = -EINVAL; + goto out; + } + + old_ctx = container_of(conf, struct ieee80211_chanctx, conf); + + ieee80211_stop_queues_by_reason(&local->hw, + IEEE80211_MAX_QUEUE_MAP, + IEEE80211_QUEUE_STOP_REASON_CHANCTX); + + ieee80211_unassign_vif_chanctx(sdata, old_ctx); + if (old_ctx->refcount == 0) + ieee80211_free_chanctx(local, old_ctx); + + if (sdata->vif.bss_conf.chandef.width != sdata->reserved_chandef.width) + local_changed |= BSS_CHANGED_BANDWIDTH; + + sdata->vif.bss_conf.chandef = sdata->reserved_chandef; + + /* unref our reservation before assigning */ + ctx->refcount--; + sdata->reserved_chanctx = NULL; + 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_wake; + } + + *changed = local_changed; + + ieee80211_recalc_chanctx_chantype(local, ctx); + ieee80211_recalc_smps_chanctx(local, ctx); + ieee80211_recalc_radar_chanctx(local, ctx); +out_wake: + ieee80211_wake_queues_by_reason(&sdata->local->hw, + IEEE80211_MAX_QUEUE_MAP, + IEEE80211_QUEUE_STOP_REASON_CHANCTX); +out: + mutex_unlock(&local->chanctx_mtx); + return ret; +} + int ieee80211_vif_change_bandwidth(struct ieee80211_sub_if_data *sdata, const struct cfg80211_chan_def *chandef, u32 *changed) diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index 8603dfb..ae8acc2 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -756,6 +756,10 @@ struct ieee80211_sub_if_data { bool csa_radar_required; struct cfg80211_chan_def csa_chandef; + /* context reservation -- protected with chanctx_mtx */ + struct ieee80211_chanctx *reserved_chanctx; + struct cfg80211_chan_def reserved_chandef; + /* used to reconfigure hardware SM PS */ struct work_struct recalc_smps; @@ -899,6 +903,7 @@ enum queue_stop_reason { IEEE80211_QUEUE_STOP_REASON_SKB_ADD, IEEE80211_QUEUE_STOP_REASON_OFFCHANNEL, IEEE80211_QUEUE_STOP_REASON_FLUSH, + IEEE80211_QUEUE_STOP_REASON_CHANCTX, }; #ifdef CONFIG_MAC80211_LEDS @@ -1776,6 +1781,15 @@ ieee80211_vif_use_channel(struct ieee80211_sub_if_data *sdata, const struct cfg80211_chan_def *chandef, enum ieee80211_chanctx_mode mode); int __must_check +ieee80211_vif_reserve_chanctx(struct ieee80211_sub_if_data *sdata, + const struct cfg80211_chan_def *chandef, + enum ieee80211_chanctx_mode mode); +int __must_check +ieee80211_vif_use_reserved_context(struct ieee80211_sub_if_data *sdata, + u32 *changed); +int ieee80211_vif_unreserve_chanctx(struct ieee80211_sub_if_data *sdata); + +int __must_check ieee80211_vif_change_bandwidth(struct ieee80211_sub_if_data *sdata, const struct cfg80211_chan_def *chandef, u32 *changed); -- 1.8.5.3