From 7236fe29fd72d17074574ba312e7f1bb9d10abaa Mon Sep 17 00:00:00 2001 From: Johannes Berg Date: Mon, 22 Mar 2010 13:42:43 -0700 Subject: [PATCH] mac80211: move netdev queue enabling to correct spot "mac80211: fix skb buffering issue" still left a race between enabling the hardware queues and the virtual interface queues. In hindsight it's totally obvious that enabling the netdev queues for a hardware queue when the hardware queue is enabled is wrong, because it could well possible that we can fill the hw queue with packets we already have pending. Thus, we must only enable the netdev queues once all the pending packets have been processed and sent off to the device. In testing, I haven't been able to trigger this race condition, but it's clearly there, possibly only when aggregation is being enabled. Signed-off-by: Johannes Berg Cc: stable@kernel.org Signed-off-by: John W. Linville --- net/mac80211/tx.c | 6 ++++++ net/mac80211/util.c | 12 ++++++------ 2 files changed, 12 insertions(+), 6 deletions(-) diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c index cbe53ed..cfc473e 100644 --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -1991,6 +1991,7 @@ static bool ieee80211_tx_pending_skb(struct ieee80211_local *local, void ieee80211_tx_pending(unsigned long data) { struct ieee80211_local *local = (struct ieee80211_local *)data; + struct ieee80211_sub_if_data *sdata; unsigned long flags; int i; bool txok; @@ -2029,6 +2030,11 @@ void ieee80211_tx_pending(unsigned long data) if (!txok) break; } + + if (skb_queue_empty(&local->pending[i])) + list_for_each_entry_rcu(sdata, &local->interfaces, list) + netif_tx_wake_queue( + netdev_get_tx_queue(sdata->dev, i)); } spin_unlock_irqrestore(&local->queue_stop_reason_lock, flags); diff --git a/net/mac80211/util.c b/net/mac80211/util.c index e6b1fba..53af570 100644 --- a/net/mac80211/util.c +++ b/net/mac80211/util.c @@ -279,13 +279,13 @@ static void __ieee80211_wake_queue(struct ieee80211_hw *hw, int queue, /* someone still has this queue stopped */ return; - if (!skb_queue_empty(&local->pending[queue])) + if (skb_queue_empty(&local->pending[queue])) { + rcu_read_lock(); + list_for_each_entry_rcu(sdata, &local->interfaces, list) + netif_tx_wake_queue(netdev_get_tx_queue(sdata->dev, queue)); + rcu_read_unlock(); + } else tasklet_schedule(&local->tx_pending_tasklet); - - rcu_read_lock(); - list_for_each_entry_rcu(sdata, &local->interfaces, list) - netif_tx_wake_queue(netdev_get_tx_queue(sdata->dev, queue)); - rcu_read_unlock(); } void ieee80211_wake_queue_by_reason(struct ieee80211_hw *hw, int queue, -- 2.7.4