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>
diff --git a/net/mac80211/key.c b/net/mac80211/key.c
index 1be3686..93ea03b 100644
--- a/net/mac80211/key.c
+++ b/net/mac80211/key.c
@@ -843,46 +843,30 @@ void ieee80211_key_free(struct ieee80211_key *key, bool delay_tailroom)
ieee80211_key_destroy(key, delay_tailroom);
}
-void ieee80211_enable_keys(struct ieee80211_sub_if_data *sdata)
+void ieee80211_reenable_keys(struct ieee80211_sub_if_data *sdata)
{
struct ieee80211_key *key;
struct ieee80211_sub_if_data *vlan;
ASSERT_RTNL();
- if (WARN_ON(!ieee80211_sdata_running(sdata)))
- return;
-
- mutex_lock(&sdata->local->key_mtx);
-
- WARN_ON_ONCE(sdata->crypto_tx_tailroom_needed_cnt ||
- sdata->crypto_tx_tailroom_pending_dec);
-
- if (sdata->vif.type == NL80211_IFTYPE_AP) {
- list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list)
- WARN_ON_ONCE(vlan->crypto_tx_tailroom_needed_cnt ||
- vlan->crypto_tx_tailroom_pending_dec);
- }
-
- list_for_each_entry(key, &sdata->key_list, list) {
- increment_tailroom_need_count(sdata);
- ieee80211_key_enable_hw_accel(key);
- }
-
- mutex_unlock(&sdata->local->key_mtx);
-}
-
-void ieee80211_reset_crypto_tx_tailroom(struct ieee80211_sub_if_data *sdata)
-{
- struct ieee80211_sub_if_data *vlan;
-
mutex_lock(&sdata->local->key_mtx);
sdata->crypto_tx_tailroom_needed_cnt = 0;
+ sdata->crypto_tx_tailroom_pending_dec = 0;
if (sdata->vif.type == NL80211_IFTYPE_AP) {
- list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list)
+ list_for_each_entry(vlan, &sdata->u.ap.vlans, u.vlan.list) {
vlan->crypto_tx_tailroom_needed_cnt = 0;
+ vlan->crypto_tx_tailroom_pending_dec = 0;
+ }
+ }
+
+ if (ieee80211_sdata_running(sdata)) {
+ list_for_each_entry(key, &sdata->key_list, list) {
+ increment_tailroom_need_count(sdata);
+ ieee80211_key_enable_hw_accel(key);
+ }
}
mutex_unlock(&sdata->local->key_mtx);
diff --git a/net/mac80211/key.h b/net/mac80211/key.h
index b8b9cd7..d6d6e89 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)))
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 286c7ee..92bfedf 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -2420,11 +2420,7 @@ int ieee80211_reconfig(struct ieee80211_local *local)
/* add back keys */
list_for_each_entry(sdata, &local->interfaces, list)
- ieee80211_reset_crypto_tx_tailroom(sdata);
-
- list_for_each_entry(sdata, &local->interfaces, list)
- if (ieee80211_sdata_running(sdata))
- ieee80211_enable_keys(sdata);
+ ieee80211_reenable_keys(sdata);
/* Reconfigure sched scan if it was interrupted by FW restart */
mutex_lock(&local->mtx);
