diff options
| author | Lior Cohen <lior2.cohen@intel.com> | 2019-08-30 14:24:49 +0300 |
|---|---|---|
| committer | Johannes Berg <johannes.berg@intel.com> | 2019-09-11 10:33:28 +0300 |
| commit | 624ff4b210ecccb0a39387993302b1a6af74176e (patch) | |
| tree | 4e99e2fd624d4bc1aeaae2bf6675c72c7497eb8a /net/mac80211/key.h | |
| parent | 1c9559734eca3dc03a4c805fbf5103349d7a7cf3 (diff) | |
| download | linux-624ff4b210ecccb0a39387993302b1a6af74176e.tar.xz | |
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 <lior2.cohen@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/20190830112451.21655-7-luca@coelho.fi
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Diffstat (limited to 'net/mac80211/key.h')
| -rw-r--r-- | net/mac80211/key.h | 4 |
1 files changed, 2 insertions, 2 deletions
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))) |