For example, let's consider the case of a 4-addr client connecting to
an AP for which AP_VLAN interface is also created, let the initial
value for tailroom_needed on the AP be 1.
* 4-addr client connects to the AP (AP: tailroom_needed = 1)
* AP will clear old keys, delay decrement of tailroom_needed count
* AP_VLAN is created, it takes the tailroom count from master
(AP_VLAN: tailroom_needed = 1, AP: tailroom_needed = 1)
* Install new key for the station, assume key is plumbed in the HW,
there won't be any change in tailroom_needed count on AP iface
* Delayed decrement of tailroom_needed count on AP
(AP: tailroom_needed = 0, AP_VLAN: tailroom_needed = 1)
Because of the delayed decrement on AP iface, tailroom_needed count goes
out of sync between AP(master iface) and AP_VLAN(slave iface) and
there would be unnecessary tailroom created for the packets going
through AP_VLAN iface.
This describes a scenario where there's *unnecessary* work done, but not
really one where we have something that's *incorrect*?
To me at least doing unnecessary things is incorrect :-D, may be we can
change the statement.
Are you saying that you found a problem with this? Did this show up in
some sort of measurements?
Not really, I have observed in my testing that there were warnings
whenever a AP_VLAN was brought down; this is done in ieee80211_free_keys.
Warnings show up every time we bring down the AP_VLAN interface(using
ifconfig); warnings apart but I thought there would be unnecessary
overhead in the tailroom expansion though the overhead may be trivial.
+++ b/net/mac80211/key.c
@@ -583,7 +583,8 @@ static void __ieee80211_key_destroy(struct ieee80211_key *key,
ieee80211_debugfs_key_remove(key);
- if (delay_tailroom) {
+ if (delay_tailroom &&
+ sdata->vif.type == NL80211_IFTYPE_STATION) {
/* see ieee80211_delayed_tailroom_dec */
sdata->crypto_tx_tailroom_pending_dec++;
schedule_delayed_work(&sdata->dec_tailroom_needed_wk,
I think you'd better change the caller, i.e. ieee80211_del_key(), and a
add a comment there that explains what's going on.
Not really sure what you were trying to tell here.
Manikanta
