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| author | Michal Kazior <michal.kazior@tieto.com> | 2013-09-23 15:34:38 +0200 |
|---|---|---|
| committer | Johannes Berg <johannes.berg@intel.com> | 2013-10-01 12:22:03 +0200 |
| commit | 0cfcefef1945c6d3f24bce1c22937cfeae07eae8 (patch) | |
| tree | 9fc8c7953e38b65832f831114df5fc0df7b83d97 | |
| parent | 15e230abaaa5a79feb25d1ef29b380e8b63aea0c (diff) | |
| download | op-kernel-dev-0cfcefef1945c6d3f24bce1c22937cfeae07eae8.zip op-kernel-dev-0cfcefef1945c6d3f24bce1c22937cfeae07eae8.tar.gz | |
mac80211: support reporting A-MSDU subframes individually
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>
| -rw-r--r-- | include/net/mac80211.h | 10 | ||||
| -rw-r--r-- | net/mac80211/rx.c | 3 |
2 files changed, 12 insertions, 1 deletions
diff --git a/include/net/mac80211.h b/include/net/mac80211.h index 8cff800..da80119 100644 --- a/include/net/mac80211.h +++ b/include/net/mac80211.h @@ -829,6 +829,15 @@ ieee80211_tx_info_clear_status(struct ieee80211_tx_info *info) * @RX_FLAG_STBC_MASK: STBC 2 bit bitmask. 1 - Nss=1, 2 - Nss=2, 3 - Nss=3 * @RX_FLAG_10MHZ: 10 MHz (half channel) was used * @RX_FLAG_5MHZ: 5 MHz (quarter channel) was used + * @RX_FLAG_AMSDU_MORE: Some drivers may prefer to report separate A-MSDU + * subframes instead of a one huge frame for performance reasons. + * All, but the last MSDU from an A-MSDU should have this flag set. E.g. + * if an A-MSDU has 3 frames, the first 2 must have the flag set, while + * the 3rd (last) one must not have this flag set. The flag is used to + * deal with retransmission/duplication recovery properly since A-MSDU + * subframes share the same sequence number. Reported subframes can be + * either regular MSDU or singly A-MSDUs. Subframes must not be + * interleaved with other frames. */ enum mac80211_rx_flags { RX_FLAG_MMIC_ERROR = BIT(0), @@ -859,6 +868,7 @@ enum mac80211_rx_flags { RX_FLAG_STBC_MASK = BIT(26) | BIT(27), RX_FLAG_10MHZ = BIT(28), RX_FLAG_5MHZ = BIT(29), + RX_FLAG_AMSDU_MORE = BIT(30), }; #define RX_FLAG_STBC_SHIFT 26 diff --git a/net/mac80211/rx.c b/net/mac80211/rx.c index 8e908e1..f0247a4 100644 --- a/net/mac80211/rx.c +++ b/net/mac80211/rx.c @@ -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)) { |
