mac80211: Add define for TX headroom reserved by mac80211 itself. (d24deb25) · Commits · 戴 / test

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@gmail.com> Acked-by:

Johannes Berg <johannes@sipsolutions.net> Signed-off-by:

John W. Linville <linville@tuxdriver.com>

include/net/mac80211.h

+6 −0

Original line number	Diff line number	Diff line
		@@ -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
		*

net/mac80211/main.c

+2 −0

Original line number	Diff line number	Diff line
		@@ -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));

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