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STRUCT TID_AMPDU_TX(9) Internals STRUCT TID_AMPDU_TX(9)

NAME

struct_tid_ampdu_tx - TID aggregation information (Tx).

SYNOPSIS

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;
};

MEMBERS

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

DESCRIPTION

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.

AUTHOR

Johannes Berg <johannes@sipsolutions.net>
Author.

COPYRIGHT

May 2018 Kernel Hackers Manual 3.16