From: Gertjan van Wingerde Date: Fri, 4 Dec 2009 22:46:54 +0000 (+0100) Subject: mac80211: Add define for TX headroom reserved by mac80211 itself. X-Git-Tag: firefly_0821_release~9833^2~3125^2~1^2~88 X-Git-Url: http://demsky.eecs.uci.edu/git/?a=commitdiff_plain;h=d24deb2580823ab0b8425790c6f5d18e2ff749d8;p=firefly-linux-kernel-4.4.55.git mac80211: Add define for TX headroom reserved by mac80211 itself. 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 --- diff --git a/include/net/mac80211.h b/include/net/mac80211.h index 2aff4906b2ae..538d6b761887 100644 --- a/include/net/mac80211.h +++ b/include/net/mac80211.h @@ -1737,6 +1737,12 @@ static inline void ieee80211_rx_ni(struct ieee80211_hw *hw, local_bh_enable(); } +/* + * 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 8116d1a96a4a..0d2d94881f1f 100644 --- a/net/mac80211/main.c +++ b/net/mac80211/main.c @@ -515,6 +515,8 @@ 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));