Return-path: Received: from mx1.redhat.com ([209.132.183.28]:56868 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932260AbdIFO1y (ORCPT ); Wed, 6 Sep 2017 10:27:54 -0400 Date: Wed, 6 Sep 2017 16:27:48 +0200 From: Stefano Brivio To: Johannes Berg Cc: Matteo Croce , linux-wireless@vger.kernel.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: hung task in mac80211 Message-ID: <20170906162748.071b040e@elisabeth> (sfid-20170906_162837_876017_44665EDC) In-Reply-To: <1504702728.13457.17.camel@sipsolutions.net> References: <1504702728.13457.17.camel@sipsolutions.net> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Sender: linux-wireless-owner@vger.kernel.org List-ID: On Wed, 06 Sep 2017 14:58:48 +0200 Johannes Berg wrote: > +void __ieee80211_start_rx_ba_session(struct sta_info *sta, > + u8 dialog_token, u16 timeout, > + u16 start_seq_num, u16 ba_policy, u16 tid, > + u16 buf_size, bool tx, bool auto_seq) > +{ > + mutex_lock(&sta->ampdu_mlme.mtx); > + ___ieee80211_start_rx_ba_session(sta, dialog_token, timeout, > + start_seq_num, ba_policy, tid, > + buf_size, tx, auto_seq); > + mutex_unlock(&sta->ampdu_mlme.mtx); > +} > + Sorry for the extended bothering :) but here, you're extending quite a bit the scope of the lock also when__ieee80211_start_rx_ba_session() is called by ieee80211_process_addba_request(). No idea what the hit can be, but we can't safely assume it's nothing either. What about simply introducing a 'ampdu_mlme_lock_held' argument instead? Something like: diff --git a/net/mac80211/agg-rx.c b/net/mac80211/agg-rx.c index 2b36eff5d97e..35a9eff1ec66 100644 --- a/net/mac80211/agg-rx.c +++ b/net/mac80211/agg-rx.c @@ -248,7 +248,8 @@ static void ieee80211_send_addba_resp(struct ieee80211_sub_if_data *sdata, u8 *d void __ieee80211_start_rx_ba_session(struct sta_info *sta, u8 dialog_token, u16 timeout, u16 start_seq_num, u16 ba_policy, u16 tid, - u16 buf_size, bool tx, bool auto_seq) + u16 buf_size, bool tx, bool auto_seq, + bool ampdu_mlme_lock_held) { struct ieee80211_local *local = sta->sdata->local; struct tid_ampdu_rx *tid_agg_rx; @@ -311,7 +312,8 @@ void __ieee80211_start_rx_ba_session(struct sta_info *sta, buf_size, sta->sta.addr); /* examine state machine */ - mutex_lock(&sta->ampdu_mlme.mtx); + if (!ampdu_mlme_lock_held) + mutex_lock(&sta->ampdu_mlme.mtx); if (test_bit(tid, sta->ampdu_mlme.agg_session_valid)) { if (sta->ampdu_mlme.tid_rx_token[tid] == dialog_token) { @@ -415,7 +417,8 @@ void __ieee80211_start_rx_ba_session(struct sta_info *sta, __clear_bit(tid, sta->ampdu_mlme.unexpected_agg); sta->ampdu_mlme.tid_rx_token[tid] = dialog_token; } - mutex_unlock(&sta->ampdu_mlme.mtx); + if (!ampdu_mlme_lock_held) + mutex_unlock(&sta->ampdu_mlme.mtx); end_no_lock: if (tx) @@ -445,7 +448,7 @@ void ieee80211_process_addba_request(struct ieee80211_local *local, __ieee80211_start_rx_ba_session(sta, dialog_token, timeout, start_seq_num, ba_policy, tid, - buf_size, true, false); + buf_size, true, false, false); } void ieee80211_manage_rx_ba_offl(struct ieee80211_vif *vif, diff --git a/net/mac80211/ht.c b/net/mac80211/ht.c index c92df492e898..59ba67e8942f 100644 --- a/net/mac80211/ht.c +++ b/net/mac80211/ht.c @@ -335,7 +335,7 @@ void ieee80211_ba_session_work(struct work_struct *work) sta->ampdu_mlme.tid_rx_manage_offl)) __ieee80211_start_rx_ba_session(sta, 0, 0, 0, 1, tid, IEEE80211_MAX_AMPDU_BUF, - false, true); + false, true, true); if (test_and_clear_bit(tid + IEEE80211_NUM_TIDS, sta->ampdu_mlme.tid_rx_manage_offl)) diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h index 2197c62a0a6e..5d494ac65853 100644 --- a/net/mac80211/ieee80211_i.h +++ b/net/mac80211/ieee80211_i.h @@ -1759,7 +1759,8 @@ void __ieee80211_stop_rx_ba_session(struct sta_info *sta, u16 tid, void __ieee80211_start_rx_ba_session(struct sta_info *sta, u8 dialog_token, u16 timeout, u16 start_seq_num, u16 ba_policy, u16 tid, - u16 buf_size, bool tx, bool auto_seq); + u16 buf_size, bool tx, bool auto_seq, + bool ampdu_mlme_lock_held); void ieee80211_sta_tear_down_BA_sessions(struct sta_info *sta, enum ieee80211_agg_stop_reason reason); void ieee80211_process_delba(struct ieee80211_sub_if_data *sdata, -- Stefano