• Toke Høiland-Jørgensen's avatar
    mac80211: Move reorder-sensitive TX handlers to after TXQ dequeue · bb42f2d1
    Toke Høiland-Jørgensen authored
    The TXQ intermediate queues can cause packet reordering when more than
    one flow is active to a single station. Since some of the wifi-specific
    packet handling (notably sequence number and encryption handling) is
    sensitive to re-ordering, things break if they are applied before the
    TXQ.
    
    This splits up the TX handlers and fast_xmit logic into two parts: An
    early part and a late part. The former is applied before TXQ enqueue,
    and the latter after dequeue. The non-TXQ path just applies both parts
    at once.
    
    Because fragments shouldn't be split up or reordered, the fragmentation
    handler is run after dequeue. Any fragments are then kept in the TXQ and
    on subsequent dequeues they take precedence over dequeueing from the FQ
    structure.
    
    This approach avoids having to scatter special cases all over the place
    for when TXQ is enabled, at the cost of making the fast_xmit and TX
    handler code slightly more complex.
    Signed-off-by: default avatarToke Høiland-Jørgensen <toke@toke.dk>
    [fix a few code-style nits, make ieee80211_xmit_fast_finish void,
     remove a useless txq->sta check]
    Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
    bb42f2d1
tx.c 121 KB