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mac80211: support reporting A-MSDU subframes individually

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Some devices may not be able to report A-MSDUs in
single buffers. Drivers for such devices were
forced to re-assemble A-MSDUs which would then
be eventually disassembled by mac80211. This could
lead to CPU cache thrashing and poor performance.

Since A-MSDU has a single sequence number all
subframes share it. This was in conflict with
retransmission/duplication recovery
(IEEE802.11-2012: 9.3.2.10).

Patch introduces a new flag that is meant to be
set for all individually reported A-MSDU subframes
except the last one. This ensures the
last_seq_ctrl is updated after the last subframe
is processed. If an A-MSDU is actually a duplicate
transmission all reported subframes will be
properly discarded.

Signed-off-by: Michal Kazior <michal.kazior@tieto.com>
[johannes: add braces that were missing even before]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
This commit is contained in:
Michal Kazior
2013-09-23 15:34:38 +02:00
committed by Johannes Berg
parent 15e230abaa
commit 0cfcefef19
2 changed files with 12 additions and 1 deletions
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3
net/mac80211/rx.c
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@@ -995,8 +995,9 @@ ieee80211_rx_h_check(struct ieee80211_rx_data *rx)
rx->sta->num_duplicates++;
}
return RX_DROP_UNUSABLE;
} else
} else if (!(status->flag & RX_FLAG_AMSDU_MORE)) {
rx->sta->last_seq_ctrl[rx->seqno_idx] = hdr->seq_ctrl;
}
}
if (unlikely(rx->skb->len < 16)) {