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Commit 2e3049b7 authored by Karl Beldan's avatar Karl Beldan Committed by Johannes Berg
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mac80211: do not compute offset from ssn in Rx AMPDU reordering buffer 



Currently, frames that go into the reordering buffer are stored at
index ieee80211_sn_sub(sn, tid_rx->ssn) % tid_rx->buf_size.

The offset calculation to the starting sequence number (SSN) is
useless and just adds overhead so simply use sn % tid_rx->buf_size.

This means the reordering buffer will start to be filled somewhere
in the middle (at SSN % buf_size) and continue to get used from
there, but there's no reason to start from the beginning.

Signed-off-by: default avatarKarl Beldan <karl.beldan@rivierawaves.com>
[rewrite commit message]
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent 8fe02e16

net/mac80211/rx.c

+5 −13
Original line number Diff line number Diff line
@@ -729,9 +729,7 @@ static void ieee80211_release_reorder_frames(struct ieee80211_sub_if_data *sdata 
	lockdep_assert_held(&tid_agg_rx->reorder_lock);



	while (ieee80211_sn_less(tid_agg_rx->head_seq_num, head_seq_num)) {

		index = ieee80211_sn_sub(tid_agg_rx->head_seq_num,

					 tid_agg_rx->ssn) %

							tid_agg_rx->buf_size;

		index = tid_agg_rx->head_seq_num % tid_agg_rx->buf_size;

		ieee80211_release_reorder_frame(sdata, tid_agg_rx, index,

						frames);

	}
@@ -757,8 +755,7 @@ static void ieee80211_sta_reorder_release(struct ieee80211_sub_if_data *sdata, 
	lockdep_assert_held(&tid_agg_rx->reorder_lock);



	/* release the buffer until next missing frame */

	index = ieee80211_sn_sub(tid_agg_rx->head_seq_num,

				 tid_agg_rx->ssn) % tid_agg_rx->buf_size;

	index = tid_agg_rx->head_seq_num % tid_agg_rx->buf_size;

	if (!tid_agg_rx->reorder_buf[index] &&

	    tid_agg_rx->stored_mpdu_num) {

		/*
@@ -793,15 +790,11 @@ static void ieee80211_sta_reorder_release(struct ieee80211_sub_if_data *sdata, 
	} else while (tid_agg_rx->reorder_buf[index]) {

		ieee80211_release_reorder_frame(sdata, tid_agg_rx, index,

						frames);

		index =	ieee80211_sn_sub(tid_agg_rx->head_seq_num,

					 tid_agg_rx->ssn) %

							tid_agg_rx->buf_size;

		index =	tid_agg_rx->head_seq_num % tid_agg_rx->buf_size;

	}



	if (tid_agg_rx->stored_mpdu_num) {

		j = index = ieee80211_sn_sub(tid_agg_rx->head_seq_num,

					     tid_agg_rx->ssn) %

							tid_agg_rx->buf_size;

		j = index = tid_agg_rx->head_seq_num % tid_agg_rx->buf_size;



		for (; j != (index - 1) % tid_agg_rx->buf_size;

		     j = (j + 1) % tid_agg_rx->buf_size) {
@@ -861,8 +854,7 @@ static bool ieee80211_sta_manage_reorder_buf(struct ieee80211_sub_if_data *sdata 


	/* Now the new frame is always in the range of the reordering buffer */



	index = ieee80211_sn_sub(mpdu_seq_num,

				 tid_agg_rx->ssn) % tid_agg_rx->buf_size;

	index = mpdu_seq_num % tid_agg_rx->buf_size;



	/* check if we already stored this frame */

	if (tid_agg_rx->reorder_buf[index]) {