package/kernel/mac80211/patches/319-mac80211-avoid-extra-memcpy-in-A-MSDU-head-creation.patch

   1 From: Michael Braun <michael-dev@fami-braun.de>
   2 Date: Sat, 15 Oct 2016 13:28:18 +0200
   3 Subject: [PATCH] mac80211: avoid extra memcpy in A-MSDU head creation
   4
   5 Signed-off-by: Michael Braun <michael-dev@fami-braun.de>
   6 Signed-off-by: Johannes Berg <johannes.berg@intel.com>
   7 ---
   8
   9 --- a/net/mac80211/tx.c
  10 +++ b/net/mac80211/tx.c
  11 @@ -3069,11 +3069,11 @@ static bool ieee80211_amsdu_prepare_head
  12         struct ieee80211_local *local = sdata->local;
  13         struct ieee80211_tx_info *info = IEEE80211_SKB_CB(skb);
  14         struct ieee80211_hdr *hdr;
  15 -       struct ethhdr amsdu_hdr;
  16 +       struct ethhdr *amsdu_hdr;
  17         int hdr_len = fast_tx->hdr_len - sizeof(rfc1042_header);
  18         int subframe_len = skb->len - hdr_len;
  19         void *data;
  20 -       u8 *qc;
  21 +       u8 *qc, *h_80211_src, *h_80211_dst;
  22
  23         if (info->flags & IEEE80211_TX_CTL_RATE_CTRL_PROBE)
  24                 return false;
  25 @@ -3081,19 +3081,22 @@ static bool ieee80211_amsdu_prepare_head
  26         if (info->control.flags & IEEE80211_TX_CTRL_AMSDU)
  27                 return true;
  28
  29 -       if (!ieee80211_amsdu_realloc_pad(local, skb, sizeof(amsdu_hdr),
  30 +       if (!ieee80211_amsdu_realloc_pad(local, skb, sizeof(*amsdu_hdr),
  31                                          &subframe_len))
  32                 return false;
  33
  34 -       amsdu_hdr.h_proto = cpu_to_be16(subframe_len);
  35 -       memcpy(amsdu_hdr.h_source, skb->data + fast_tx->sa_offs, ETH_ALEN);
  36 -       memcpy(amsdu_hdr.h_dest, skb->data + fast_tx->da_offs, ETH_ALEN);
  37 -
  38 -       data = skb_push(skb, sizeof(amsdu_hdr));
  39 -       memmove(data, data + sizeof(amsdu_hdr), hdr_len);
  40 -       memcpy(data + hdr_len, &amsdu_hdr, sizeof(amsdu_hdr));
  41 -
  42 +       data = skb_push(skb, sizeof(*amsdu_hdr));
  43 +       memmove(data, data + sizeof(*amsdu_hdr), hdr_len);
  44         hdr = data;
  45 +       amsdu_hdr = data + hdr_len;
  46 +       /* h_80211_src/dst is addr* field within hdr */
  47 +       h_80211_src = data + fast_tx->sa_offs;
  48 +       h_80211_dst = data + fast_tx->da_offs;
  49 +
  50 +       amsdu_hdr->h_proto = cpu_to_be16(subframe_len);
  51 +       ether_addr_copy(amsdu_hdr->h_source, h_80211_src);
  52 +       ether_addr_copy(amsdu_hdr->h_dest, h_80211_dst);
  53 +
  54         qc = ieee80211_get_qos_ctl(hdr);
  55         *qc |= IEEE80211_QOS_CTL_A_MSDU_PRESENT;
  56