From c70f59a2a007c57843195a93c3b7308204e0a5ab Mon Sep 17 00:00:00 2001 From: Ido Yariv Date: Tue, 29 Jul 2014 15:39:14 +0300 Subject: mac80211: don't resize skbs needlessly Header-less cloned skbs with sufficient headroom need not be cloned unless the tailroom is going to be modified. Fix ieee80211_skb_resize so it would only resize cloned skbs if either the header isn't released or the tailroom is going to be modified. Some drivers might have assumed that skbs are never cloned, so add a HW flag that explicitly permits cloned TX skbs. Drivers which do not modify TX skbs should set this flag to avoid copying skbs. Signed-off-by: Ido Yariv Signed-off-by: Emmanuel Grumbach Signed-off-by: Johannes Berg --- net/mac80211/tx.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-) (limited to 'net/mac80211') diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c index 2051cc6..925c39f 100644 --- a/net/mac80211/tx.c +++ b/net/mac80211/tx.c @@ -1478,7 +1478,10 @@ static int ieee80211_skb_resize(struct ieee80211_sub_if_data *sdata, tail_need = max_t(int, tail_need, 0); } - if (skb_cloned(skb)) + if (skb_cloned(skb) && + (!(local->hw.flags & IEEE80211_HW_SUPPORTS_CLONED_SKBS) || + !skb_clone_writable(skb, ETH_HLEN) || + sdata->crypto_tx_tailroom_needed_cnt)) I802_DEBUG_INC(local->tx_expand_skb_head_cloned); else if (head_need || tail_need) I802_DEBUG_INC(local->tx_expand_skb_head); -- cgit v1.1