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 <gwingerde@xxxxxxxxx> Cc: Johannes Berg <johannes@xxxxxxxxxxxxxxxx> --- include/net/mac80211.h | 6 ++++++ net/mac80211/main.c | 2 ++ 2 files changed, 8 insertions(+), 0 deletions(-) diff --git a/include/net/mac80211.h b/include/net/mac80211.h index 3754ea4..a113458 100644 --- a/include/net/mac80211.h +++ b/include/net/mac80211.h @@ -1727,6 +1727,12 @@ 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 dd8ec8d..f35d4aa 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)); -- 1.6.5.3 -- To unsubscribe from this list: send the line "unsubscribe linux-wireless" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
