From 624ff4b210ecccb0a39387993302b1a6af74176e Mon Sep 17 00:00:00 2001 From: Lior Cohen Date: Fri, 30 Aug 2019 14:24:49 +0300 Subject: mac80211: clear crypto tx tailroom counter upon keys enable In case we got a fw restart while roaming from encrypted AP to non-encrypted one, we might end up with hitting a warning on the pending counter crypto_tx_tailroom_pending_dec having a non-zero value. The following comment taken from net/mac80211/key.c explains the rational for the delayed tailroom needed: /* * The reason for the delayed tailroom needed decrementing is to * make roaming faster: during roaming, all keys are first deleted * and then new keys are installed. The first new key causes the * crypto_tx_tailroom_needed_cnt to go from 0 to 1, which invokes * the cost of synchronize_net() (which can be slow). Avoid this * by deferring the crypto_tx_tailroom_needed_cnt decrementing on * key removal for a while, so if we roam the value is larger than * zero and no 0->1 transition happens. * * The cost is that if the AP switching was from an AP with keys * to one without, we still allocate tailroom while it would no * longer be needed. However, in the typical (fast) roaming case * within an ESS this usually won't happen. */ The next flow lead to the warning eventually reported as a bug: 1. Disconnect from encrypted AP 2. Set crypto_tx_tailroom_pending_dec = 1 for the key 3. Schedule work 4. Reconnect to non-encrypted AP 5. Add a new key, setting the tailroom counter = 1 6. Got FW restart while pending counter is set ---> hit the warning While on it, the ieee80211_reset_crypto_tx_tailroom() func was merged into its single caller ieee80211_reenable_keys (previously called ieee80211_enable_keys). Also, we reset the crypto_tx_tailroom_pending_dec and remove the counters warning as we just reset both. Signed-off-by: Lior Cohen Signed-off-by: Luca Coelho Link: https://lore.kernel.org/r/20190830112451.21655-7-luca@coelho.fi Signed-off-by: Johannes Berg --- net/mac80211/key.h | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) (limited to 'net/mac80211/key.h') diff --git a/net/mac80211/key.h b/net/mac80211/key.h index b8b9cd743bf4..d6d6e89cf7dd 100644 --- a/net/mac80211/key.h +++ b/net/mac80211/key.h @@ -2,6 +2,7 @@ /* * Copyright 2002-2004, Instant802 Networks, Inc. * Copyright 2005, Devicescape Software, Inc. + * Copyright (C) 2019 Intel Corporation */ #ifndef IEEE80211_KEY_H @@ -156,8 +157,7 @@ void ieee80211_free_keys(struct ieee80211_sub_if_data *sdata, bool force_synchronize); void ieee80211_free_sta_keys(struct ieee80211_local *local, struct sta_info *sta); -void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata); -void ieee80211_reset_crypto_tx_tailroom(struct ieee80211_sub_if_data *sdata); +void ieee80211_reenable_keys(struct ieee80211_sub_if_data *sdata); #define key_mtx_dereference(local, ref) \ rcu_dereference_protected(ref, lockdep_is_held(&((local)->key_mtx))) -- cgit v1.2.3