struct_tid_ampdu_tx (9)

struct tid_ampdu_tx {
  struct rcu_head rcu_head;
  struct timer_list session_timer;
  struct timer_list addba_resp_timer;
  struct sk_buff_head pending;
  unsigned long state;
  unsigned long last_tx;
  u16 timeout;
  u8 dialog_token;
  u8 stop_initiator;
  bool tx_stop;
  u8 buf_size;
  u16 failed_bar_ssn;
  bool bar_pending;
};

rcu_head

rcu head for freeing structure

session_timer

check if we keep Tx-ing on the TID (by timeout value)

addba_resp_timer

timer for peer's response to addba request

pending

pending frames queue -- use sta's spinlock to protect

state

session state (see above)

last_tx

jiffies of last tx activity

timeout

session timeout value to be filled in ADDBA requests

dialog_token

dialog token for aggregation session

stop_initiator

initiator of a session stop

tx_stop

TX DelBA frame when stopping

buf_size

reorder buffer size at receiver

failed_bar_ssn

ssn of the last failed BAR tx attempt

bar_pending

BAR needs to be re-sent

This structure's lifetime is managed by RCU, assignments to the array holding it must hold the aggregation mutex.

The TX path can access it under RCU lock-free if, and only if, the state has the flag HT_AGG_STATE_OPERATIONAL set. Otherwise, the TX path must also acquire the spinlock and re-check the state, see comments in the tx code touching it.

Johannes Berg <[email protected]>

Author.