From: Gertjan van Wingerde Date: Sun, 10 Oct 2010 18:25:33 +0000 (+0100) Subject: mac80211: Add define for TX headroom reserved by mac80211 itself. X-Git-Tag: v2.6.32.40~58 X-Git-Url: http://git.ipfire.org/gitweb.cgi?a=commitdiff_plain;h=2b5f7f94872ef2ed281783017e1a6ac787b8c107;p=thirdparty%2Fkernel%2Fstable.git mac80211: Add define for TX headroom reserved by mac80211 itself. commit d24deb2580823ab0b8425790c6f5d18e2ff749d8 upstream. Add a definition of the amount of TX headroom reserved by mac80211 itself for its own purposes. Also add BUILD_BUG_ON to validate the value. This define can then be used by drivers to request additional TX headroom in the most efficient manner. Signed-off-by: Gertjan van Wingerde Acked-by: Johannes Berg Signed-off-by: John W. Linville [bwh: Adjust context for 2.6.32] Signed-off-by: Greg Kroah-Hartman --- diff --git a/include/net/mac80211.h b/include/net/mac80211.h index c39ed07929487..a2bd2f98b63f7 100644 --- a/include/net/mac80211.h +++ b/include/net/mac80211.h @@ -1700,6 +1700,12 @@ void ieee80211_rx(struct ieee80211_hw *hw, struct sk_buff *skb); */ void ieee80211_rx_irqsafe(struct ieee80211_hw *hw, struct sk_buff *skb); +/* + * The TX headroom reserved by mac80211 for its own tx_status functions. + * This is enough for the radiotap header. + */ +#define IEEE80211_TX_STATUS_HEADROOM 13 + /** * ieee80211_tx_status - transmit status callback * diff --git a/net/mac80211/main.c b/net/mac80211/main.c index 19fbd25a705b2..2dfe1768e2ab1 100644 --- a/net/mac80211/main.c +++ b/net/mac80211/main.c @@ -859,6 +859,8 @@ int ieee80211_register_hw(struct ieee80211_hw *hw) * and we need some headroom for passing the frame to monitor * interfaces, but never both at the same time. */ + BUILD_BUG_ON(IEEE80211_TX_STATUS_HEADROOM != + sizeof(struct ieee80211_tx_status_rtap_hdr)); local->tx_headroom = max_t(unsigned int , local->hw.extra_tx_headroom, sizeof(struct ieee80211_tx_status_rtap_hdr));