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yaml
---
r: 203007
b: refs/heads/master
c: a6a67db
h: refs/heads/master
i:
  203005: 9f50604
  203003: ab40f3b
  202999: c30214b
  202991: 71c0051
  202975: 24c292a
  202943: bd4a035
  202879: ad9a131
  202751: 09c99c4
v: v3
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Johannes Berg authored and John W. Linville committed Jun 14, 2010
1 parent e45057c commit e8902f6
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Showing 4 changed files with 52 additions and 41 deletions.
2 changes: 1 addition & 1 deletion [refs]
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Original file line number Diff line number Diff line change
@@ -1,2 +1,2 @@
---
refs/heads/master: 5d22c89b9bea17a0e48e7534a9b237885e2c0809
refs/heads/master: a6a67db2bc89d2b1ff07e0817f11235c20d2c329
77 changes: 47 additions & 30 deletions trunk/net/mac80211/agg-tx.c
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Original file line number Diff line number Diff line change
Expand Up @@ -220,6 +220,41 @@ static inline int ieee80211_ac_from_tid(int tid)
return ieee802_1d_to_ac[tid & 7];
}

/*
* When multiple aggregation sessions on multiple stations
* are being created/destroyed simultaneously, we need to
* refcount the global queue stop caused by that in order
* to not get into a situation where one of the aggregation
* setup or teardown re-enables queues before the other is
* ready to handle that.
*
* These two functions take care of this issue by keeping
* a global "agg_queue_stop" refcount.
*/
static void __acquires(agg_queue)
ieee80211_stop_queue_agg(struct ieee80211_local *local, int tid)
{
int queue = ieee80211_ac_from_tid(tid);

if (atomic_inc_return(&local->agg_queue_stop[queue]) == 1)
ieee80211_stop_queue_by_reason(
&local->hw, queue,
IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
__acquire(agg_queue);
}

static void __releases(agg_queue)
ieee80211_wake_queue_agg(struct ieee80211_local *local, int tid)
{
int queue = ieee80211_ac_from_tid(tid);

if (atomic_dec_return(&local->agg_queue_stop[queue]) == 0)
ieee80211_wake_queue_by_reason(
&local->hw, queue,
IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
__release(agg_queue);
}

int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
{
struct sta_info *sta = container_of(pubsta, struct sta_info, sta);
Expand Down Expand Up @@ -263,7 +298,6 @@ int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
}

spin_lock_bh(&sta->lock);
spin_lock(&local->ampdu_lock);

/* we have tried too many times, receiver does not want A-MPDU */
if (sta->ampdu_mlme.addba_req_num[tid] > HT_AGG_MAX_RETRIES) {
Expand All @@ -289,9 +323,7 @@ int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
* which would require us to put them to the AC pending
* afterwards which just makes the code more complex.
*/
ieee80211_stop_queue_by_reason(
&local->hw, ieee80211_ac_from_tid(tid),
IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
ieee80211_stop_queue_agg(local, tid);

/* prepare A-MPDU MLME for Tx aggregation */
tid_tx = kzalloc(sizeof(struct tid_ampdu_tx), GFP_ATOMIC);
Expand Down Expand Up @@ -327,11 +359,7 @@ int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
rcu_assign_pointer(sta->ampdu_mlme.tid_tx[tid], tid_tx);

/* Driver vetoed or OKed, but we can take packets again now */
ieee80211_wake_queue_by_reason(
&local->hw, ieee80211_ac_from_tid(tid),
IEEE80211_QUEUE_STOP_REASON_AGGREGATION);

spin_unlock(&local->ampdu_lock);
ieee80211_wake_queue_agg(local, tid);

/* activate the timer for the recipient's addBA response */
tid_tx->addba_resp_timer.expires = jiffies + ADDBA_RESP_INTERVAL;
Expand All @@ -358,31 +386,25 @@ int ieee80211_start_tx_ba_session(struct ieee80211_sta *pubsta, u16 tid)
err_free:
kfree(tid_tx);
err_wake_queue:
ieee80211_wake_queue_by_reason(
&local->hw, ieee80211_ac_from_tid(tid),
IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
ieee80211_wake_queue_agg(local, tid);
err_unlock_sta:
spin_unlock(&local->ampdu_lock);
spin_unlock_bh(&sta->lock);
return ret;
}
EXPORT_SYMBOL(ieee80211_start_tx_ba_session);

/*
* splice packets from the STA's pending to the local pending,
* requires a call to ieee80211_agg_splice_finish and holding
* local->ampdu_lock across both calls.
* requires a call to ieee80211_agg_splice_finish later
*/
static void ieee80211_agg_splice_packets(struct ieee80211_local *local,
struct tid_ampdu_tx *tid_tx,
u16 tid)
static void __acquires(agg_queue)
ieee80211_agg_splice_packets(struct ieee80211_local *local,
struct tid_ampdu_tx *tid_tx, u16 tid)
{
int queue = ieee80211_ac_from_tid(tid);
unsigned long flags;
u16 queue = ieee80211_ac_from_tid(tid);

ieee80211_stop_queue_by_reason(
&local->hw, queue,
IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
ieee80211_stop_queue_agg(local, tid);

if (WARN(!tid_tx, "TID %d gone but expected when splicing aggregates"
" from the pending queue\n", tid))
Expand All @@ -397,11 +419,10 @@ static void ieee80211_agg_splice_packets(struct ieee80211_local *local,
}
}

static void ieee80211_agg_splice_finish(struct ieee80211_local *local, u16 tid)
static void __releases(agg_queue)
ieee80211_agg_splice_finish(struct ieee80211_local *local, u16 tid)
{
ieee80211_wake_queue_by_reason(
&local->hw, ieee80211_ac_from_tid(tid),
IEEE80211_QUEUE_STOP_REASON_AGGREGATION);
ieee80211_wake_queue_agg(local, tid);
}

/* caller must hold sta->lock */
Expand All @@ -414,7 +435,6 @@ static void ieee80211_agg_tx_operational(struct ieee80211_local *local,
printk(KERN_DEBUG "Aggregation is on for tid %d\n", tid);
#endif

spin_lock(&local->ampdu_lock);
ieee80211_agg_splice_packets(local, sta->ampdu_mlme.tid_tx[tid], tid);
/*
* Now mark as operational. This will be visible
Expand All @@ -423,7 +443,6 @@ static void ieee80211_agg_tx_operational(struct ieee80211_local *local,
*/
set_bit(HT_AGG_STATE_OPERATIONAL, &sta->ampdu_mlme.tid_tx[tid]->state);
ieee80211_agg_splice_finish(local, tid);
spin_unlock(&local->ampdu_lock);

drv_ampdu_action(local, sta->sdata,
IEEE80211_AMPDU_TX_OPERATIONAL,
Expand Down Expand Up @@ -604,7 +623,6 @@ void ieee80211_stop_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u8 tid)
* more.
*/

spin_lock(&local->ampdu_lock);
ieee80211_agg_splice_packets(local, tid_tx, tid);

/* future packets must not find the tid_tx struct any more */
Expand All @@ -613,7 +631,6 @@ void ieee80211_stop_tx_ba_cb(struct ieee80211_vif *vif, u8 *ra, u8 tid)
ieee80211_agg_splice_finish(local, tid);

call_rcu(&tid_tx->rcu_head, kfree_tid_tx);
spin_unlock(&local->ampdu_lock);

spin_unlock_bh(&sta->lock);
rcu_read_unlock();
Expand Down
8 changes: 1 addition & 7 deletions trunk/net/mac80211/ieee80211_i.h
View file
Original file line number Diff line number Diff line change
Expand Up @@ -723,13 +723,7 @@ struct ieee80211_local {
struct sk_buff_head pending[IEEE80211_MAX_QUEUES];
struct tasklet_struct tx_pending_tasklet;

/*
* This lock is used to prevent concurrent A-MPDU
* session start/stop processing, this thus also
* synchronises the ->ampdu_action() callback to
* drivers and limits it to one at a time.
*/
spinlock_t ampdu_lock;
atomic_t agg_queue_stop[IEEE80211_MAX_QUEUES];

/* number of interfaces with corresponding IFF_ flags */
atomic_t iff_allmultis, iff_promiscs;
Expand Down
6 changes: 3 additions & 3 deletions trunk/net/mac80211/main.c
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Original file line number Diff line number Diff line change
Expand Up @@ -463,8 +463,10 @@ struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,

sta_info_init(local);

for (i = 0; i < IEEE80211_MAX_QUEUES; i++)
for (i = 0; i < IEEE80211_MAX_QUEUES; i++) {
skb_queue_head_init(&local->pending[i]);
atomic_set(&local->agg_queue_stop[i], 0);
}
tasklet_init(&local->tx_pending_tasklet, ieee80211_tx_pending,
(unsigned long)local);

Expand All @@ -475,8 +477,6 @@ struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,
skb_queue_head_init(&local->skb_queue);
skb_queue_head_init(&local->skb_queue_unreliable);

spin_lock_init(&local->ampdu_lock);

return local_to_hw(local);
}
EXPORT_SYMBOL(ieee80211_alloc_hw);
Expand Down

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