mac80211: Fix tx queue handling during scans
Scans currently work by stopping the netdev tx queues but leaving the
mac80211 queues active. This stops the flow of incoming packets while
still allowing mac80211 to transmit nullfunc and probe request frames to
facilitate scanning. However, the driver may try to wake the mac80211
queues while in this state, which will also wake the netdev queues.
To prevent this, add a new queue stop reason,
IEEE80211_QUEUE_STOP_REASON_OFFCHANNEL, to be used when stopping the tx
queues for off-channel operation. This prevents the netdev queues from
waking when a driver wakes the mac80211 queues.
This also stops all frames from being transmitted, even those meant to
be sent off-channel. Add a new tx control flag,
IEEE80211_TX_CTL_OFFCHAN_TX_OK, which allows frames to be transmitted
when the queues are stopped only for the off-channel stop reason. Update
all locations transmitting off-channel frames to use this flag.
Signed-off-by: Seth Forshee <seth.forshee@canonical.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index 86ad2c3..0eaa909 100644
--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -399,6 +399,9 @@
* @IEEE80211_TX_CTL_RATE_CTRL_PROBE: internal to mac80211, can be
* set by rate control algorithms to indicate probe rate, will
* be cleared for fragmented frames (except on the last fragment)
+ * @IEEE80211_TX_INTFL_OFFCHAN_TX_OK: Internal to mac80211. Used to indicate
+ * that a frame can be transmitted while the queues are stopped for
+ * off-channel operation.
* @IEEE80211_TX_INTFL_NEED_TXPROCESSING: completely internal to mac80211,
* used to indicate that a pending frame requires TX processing before
* it can be sent out.
@@ -464,6 +467,7 @@
IEEE80211_TX_STAT_AMPDU = BIT(10),
IEEE80211_TX_STAT_AMPDU_NO_BACK = BIT(11),
IEEE80211_TX_CTL_RATE_CTRL_PROBE = BIT(12),
+ IEEE80211_TX_INTFL_OFFCHAN_TX_OK = BIT(13),
IEEE80211_TX_INTFL_NEED_TXPROCESSING = BIT(14),
IEEE80211_TX_INTFL_RETRIED = BIT(15),
IEEE80211_TX_INTFL_DONT_ENCRYPT = BIT(16),
diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index 8f6b593..e3dec80 100644
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -2749,7 +2749,8 @@
goto out_unlock;
}
- IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_CTL_TX_OFFCHAN;
+ IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_CTL_TX_OFFCHAN |
+ IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
if (local->hw.flags & IEEE80211_HW_QUEUE_CONTROL)
IEEE80211_SKB_CB(skb)->hw_queue =
local->hw.offchannel_tx_hw_queue;
diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 5635dfc..76cdcfc 100644
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -809,6 +809,7 @@
IEEE80211_QUEUE_STOP_REASON_AGGREGATION,
IEEE80211_QUEUE_STOP_REASON_SUSPEND,
IEEE80211_QUEUE_STOP_REASON_SKB_ADD,
+ IEEE80211_QUEUE_STOP_REASON_OFFCHANNEL,
};
#ifdef CONFIG_MAC80211_LEDS
diff --git a/net/mac80211/mlme.c b/net/mac80211/mlme.c
index 76cacdb..efb2276 100644
--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -685,7 +685,8 @@
if (powersave)
nullfunc->frame_control |= cpu_to_le16(IEEE80211_FCTL_PM);
- IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT;
+ IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_INTFL_DONT_ENCRYPT |
+ IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
if (ifmgd->flags & (IEEE80211_STA_BEACON_POLL |
IEEE80211_STA_CONNECTION_POLL))
IEEE80211_SKB_CB(skb)->flags |= IEEE80211_TX_CTL_USE_MINRATE;
diff --git a/net/mac80211/offchannel.c b/net/mac80211/offchannel.c
index 82baf5b..4c3ee3e 100644
--- a/net/mac80211/offchannel.c
+++ b/net/mac80211/offchannel.c
@@ -113,6 +113,10 @@
* notify the AP about us leaving the channel and stop all
* STA interfaces.
*/
+
+ ieee80211_stop_queues_by_reason(&local->hw,
+ IEEE80211_QUEUE_STOP_REASON_OFFCHANNEL);
+
mutex_lock(&local->iflist_mtx);
list_for_each_entry(sdata, &local->interfaces, list) {
if (!ieee80211_sdata_running(sdata))
@@ -133,12 +137,9 @@
sdata, BSS_CHANGED_BEACON_ENABLED);
}
- if (sdata->vif.type != NL80211_IFTYPE_MONITOR) {
- netif_tx_stop_all_queues(sdata->dev);
- if (sdata->vif.type == NL80211_IFTYPE_STATION &&
- sdata->u.mgd.associated)
- ieee80211_offchannel_ps_enable(sdata);
- }
+ if (sdata->vif.type == NL80211_IFTYPE_STATION &&
+ sdata->u.mgd.associated)
+ ieee80211_offchannel_ps_enable(sdata);
}
mutex_unlock(&local->iflist_mtx);
}
@@ -166,20 +167,6 @@
sdata->u.mgd.associated)
ieee80211_offchannel_ps_disable(sdata);
- if (sdata->vif.type != NL80211_IFTYPE_MONITOR) {
- /*
- * This may wake up queues even though the driver
- * currently has them stopped. This is not very
- * likely, since the driver won't have gotten any
- * (or hardly any) new packets while we weren't
- * on the right channel, and even if it happens
- * it will at most lead to queueing up one more
- * packet per queue in mac80211 rather than on
- * the interface qdisc.
- */
- netif_tx_wake_all_queues(sdata->dev);
- }
-
if (test_and_clear_bit(SDATA_STATE_OFFCHANNEL_BEACON_STOPPED,
&sdata->state)) {
sdata->vif.bss_conf.enable_beacon = true;
@@ -188,6 +175,9 @@
}
}
mutex_unlock(&local->iflist_mtx);
+
+ ieee80211_wake_queues_by_reason(&local->hw,
+ IEEE80211_QUEUE_STOP_REASON_OFFCHANNEL);
}
void ieee80211_handle_roc_started(struct ieee80211_roc_work *roc)
diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index edd47d9..d9e2df9 100644
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -382,6 +382,11 @@
int i;
struct ieee80211_sub_if_data *sdata;
enum ieee80211_band band = local->hw.conf.channel->band;
+ u32 tx_flags;
+
+ tx_flags = IEEE80211_TX_INTFL_OFFCHAN_TX_OK;
+ if (local->scan_req->no_cck)
+ tx_flags |= IEEE80211_TX_CTL_NO_CCK_RATE;
sdata = rcu_dereference_protected(local->scan_sdata,
lockdep_is_held(&local->mtx));
@@ -393,9 +398,7 @@
local->scan_req->ssids[i].ssid_len,
local->scan_req->ie, local->scan_req->ie_len,
local->scan_req->rates[band], false,
- local->scan_req->no_cck ?
- IEEE80211_TX_CTL_NO_CCK_RATE : 0,
- local->hw.conf.channel, true);
+ tx_flags, local->hw.conf.channel, true);
/*
* After sending probe requests, wait for probe responses
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 2ef0e19b..f476aa6 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -1230,6 +1230,21 @@
spin_lock_irqsave(&local->queue_stop_reason_lock, flags);
if (local->queue_stop_reasons[q] ||
(!txpending && !skb_queue_empty(&local->pending[q]))) {
+ if (unlikely(info->flags &
+ IEEE80211_TX_INTFL_OFFCHAN_TX_OK &&
+ local->queue_stop_reasons[q] &
+ ~BIT(IEEE80211_QUEUE_STOP_REASON_OFFCHANNEL))) {
+ /*
+ * Drop off-channel frames if queues are stopped
+ * for any reason other than off-channel
+ * operation. Never queue them.
+ */
+ spin_unlock_irqrestore(
+ &local->queue_stop_reason_lock, flags);
+ ieee80211_purge_tx_queue(&local->hw, skbs);
+ return true;
+ }
+
/*
* Since queue is stopped, queue up frames for later
* transmission from the tx-pending tasklet when the