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Commit 73a72a81 authored by Johannes Berg's avatar Johannes Berg Committed by John W. Linville
Browse files

mac80211: update aggregation documentation 



Even before the recent changes, the documentation
for TX aggregation was somewhat out of date. Update
it and also add documentation for the RX side.

Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
parent 85ad181e

net/mac80211/agg-rx.c

+23 −0
Original line number Diff line number Diff line
@@ -13,6 +13,29 @@ 
 * published by the Free Software Foundation.

 */



/**

 * DOC: RX A-MPDU aggregation

 *

 * Aggregation on the RX side requires only implementing the

 * @ampdu_action callback that is invoked to start/stop any

 * block-ack sessions for RX aggregation.

 *

 * When RX aggregation is started by the peer, the driver is

 * notified via @ampdu_action function, with the

 * %IEEE80211_AMPDU_RX_START action, and may reject the request

 * in which case a negative response is sent to the peer, if it

 * accepts it a positive response is sent.

 *

 * While the session is active, the device/driver are required

 * to de-aggregate frames and pass them up one by one to mac80211,

 * which will handle the reorder buffer.

 *

 * When the aggregation session is stopped again by the peer or

 * ourselves, the driver's @ampdu_action function will be called

 * with the action %IEEE80211_AMPDU_RX_STOP. In this case, the

 * call must not fail.

 */



#include <linux/ieee80211.h>

#include <linux/slab.h>

#include <net/mac80211.h>

net/mac80211/agg-tx.c

+27 −16
Original line number Diff line number Diff line
@@ -21,28 +21,39 @@ 
#include "wme.h"



/**

 * DOC: TX aggregation

 * DOC: TX A-MPDU aggregation

 *

 * Aggregation on the TX side requires setting the hardware flag

 * %IEEE80211_HW_AMPDU_AGGREGATION as well as, if present, the @ampdu_queues

 * hardware parameter to the number of hardware AMPDU queues. If there are no

 * hardware queues then the driver will (currently) have to do all frame

 * buffering.

 * %IEEE80211_HW_AMPDU_AGGREGATION. The driver will then be handed

 * packets with a flag indicating A-MPDU aggregation. The driver

 * or device is responsible for actually aggregating the frames,

 * as well as deciding how many and which to aggregate.

 *

 * When TX aggregation is started by some subsystem (usually the rate control

 * algorithm would be appropriate) by calling the

 * ieee80211_start_tx_ba_session() function, the driver will be notified via

 * its @ampdu_action function, with the %IEEE80211_AMPDU_TX_START action.

 * When TX aggregation is started by some subsystem (usually the rate

 * control algorithm would be appropriate) by calling the

 * ieee80211_start_tx_ba_session() function, the driver will be

 * notified via its @ampdu_action function, with the

 * %IEEE80211_AMPDU_TX_START action.

 *

 * In response to that, the driver is later required to call the

 * ieee80211_start_tx_ba_cb() (or ieee80211_start_tx_ba_cb_irqsafe())

 * function, which will start the aggregation session.

 * ieee80211_start_tx_ba_cb_irqsafe() function, which will really

 * start the aggregation session after the peer has also responded.

 * If the peer responds negatively, the session will be stopped

 * again right away. Note that it is possible for the aggregation

 * session to be stopped before the driver has indicated that it

 * is done setting it up, in which case it must not indicate the

 * setup completion.

 *

 * Similarly, when the aggregation session is stopped by

 * ieee80211_stop_tx_ba_session(), the driver's @ampdu_action function will

 * be called with the action %IEEE80211_AMPDU_TX_STOP. In this case, the

 * call must not fail, and the driver must later call ieee80211_stop_tx_ba_cb()

 * (or ieee80211_stop_tx_ba_cb_irqsafe()).

 * Also note that, since we also need to wait for a response from

 * the peer, the driver is notified of the completion of the

 * handshake by the %IEEE80211_AMPDU_TX_OPERATIONAL action to the

 * @ampdu_action callback.

 *

 * Similarly, when the aggregation session is stopped by the peer

 * or something calling ieee80211_stop_tx_ba_session(), the driver's

 * @ampdu_action function will be called with the action

 * %IEEE80211_AMPDU_TX_STOP. In this case, the call must not fail,

 * and the driver must later call ieee80211_stop_tx_ba_cb_irqsafe().

 */



static void ieee80211_send_addba_request(struct ieee80211_sub_if_data *sdata,