On Thu, Jul 24, 2008 at 12:41 AM, Tomas Winkler <tomasw@xxxxxxxxx> wrote:
> Here is the scenario. This is happening with what we have in
> wireless-testing code
>
> When hw queue get full we call
> ieeee80211_stop_queue(dev, q);
>
> When this is happens in the middle of the fragmentation . This is
> easiest to reproduces with fragmentation but probably happens also in
> other cases.
>
> int __ieee80211_tx()
> ....
>
> if (netif_subqueue_stopped(local->mdev,
> tx->extra_frag[i]))
> return IEEE80211_TX_FRAG_AGAIN;
>
>
> The fragment should stored into local->queues_pending[queue]
> (Actually I'm not sure it is)
>
> now when we HW queue got cleared a bit we call wake queues where
> tx_pending_tasklet is woken up ( queue is not woken up here)
>
> void ieee80211_wake_queue(struct ieee80211_hw *hw, int queue)
> {
> struct ieee80211_local *local = hw_to_local(hw);
>
> if (test_bit(queue, local->queues_pending)) {
> tasklet_schedule(&local->tx_pending_tasklet);
> }
> ..... <snip>
> }
>
> The check if the queue is open causes that queue is actually never
> woken up so traffic is stalled. However removing this line causes some
> other panic I didn't have time to process.
>
> void ieee80211_tx_pending(unsigned long data)
> {
> <snip>
>
> netif_tx_lock_bh(dev);
> for (i = 0; i < ieee80211_num_regular_queues(&local->hw); i++) {
> /* Check that this queue is ok */
> if (__netif_subqueue_stopped(local->mdev, i))
> --- This line causes that fact that the actual wake queue is never
> called.
> continue;
>
> if (!test_bit(i, local->queues_pending)) {
> ieee80211_wake_queue(&local->hw, i);
> continue;
> }
> </snip>
This patch solves the problem. Just I'm not sure about not locking a cross
netif_start_subqueue(local->mdev, queue);
pending assumes that no new packets are to be transmitted before
pending packets are cleared out.
This patch make mac80211 transmit correctly fragmented packet after
stopping queues.
Signed-off-by: Tomas Winkler <tomas.winkler@xxxxxxxxx>
---
net/mac80211/tx.c | 8 +++++---
net/mac80211/util.c | 7 +++++++
2 files changed, 12 insertions(+), 3 deletions(-)
diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 2b912cf..db6540e 100644
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -1061,13 +1061,15 @@ static int ieee80211_tx_prepare(struct
ieee80211_tx_data *tx,
static int __ieee80211_tx(struct ieee80211_local *local, struct sk_buff *skb,
struct ieee80211_tx_data *tx)
{
- struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
+ struct ieee80211_tx_info *info;
int ret, i;
- if (netif_subqueue_stopped(local->mdev, skb))
- return IEEE80211_TX_AGAIN;
if (skb) {
+ if (netif_subqueue_stopped(local->mdev, skb))
+ return IEEE80211_TX_AGAIN;
+ info = IEEE80211_SKB_CB(skb);
+
ieee80211_dump_frame(wiphy_name(local->hw.wiphy),
"TX to low-level driver", skb);
ret = local->ops->tx(local_to_hw(local), skb);
diff --git a/net/mac80211/util.c b/net/mac80211/util.c
index 89ce4e0..8028744 100644
--- a/net/mac80211/util.c
+++ b/net/mac80211/util.c
@@ -361,6 +361,13 @@ void ieee80211_wake_queue(struct ieee80211_hw
*hw, int queue)
struct ieee80211_local *local = hw_to_local(hw);
if (test_bit(queue, local->queues_pending)) {
+ /* don't call scheduler just open the queue */
+ if (ieee80211_is_multiqueue(local)) {
+ netif_start_subqueue(local->mdev, queue);
+ } else {
+ WARN_ON(queue != 0);
+ netif_start_queue(local->mdev);
+ }
tasklet_schedule(&local->tx_pending_tasklet);
} else {
if (ieee80211_is_multiqueue(local)) {
Tomas
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