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authorGertjan van Wingerde <gwingerde@gmail.com>2010-10-10 19:25:33 +0100
committerGreg Kroah-Hartman <gregkh@suse.de>2011-05-09 15:55:22 -0700
commit2b5f7f94872ef2ed281783017e1a6ac787b8c107 (patch)
treec4b62532a8d4526168b97660f31b3a14cb53b3d2
parent5e93019e4a06ade55e91010371ee22a218190567 (diff)
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 <gwingerde@gmail.com> Acked-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com> [bwh: Adjust context for 2.6.32] Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
-rw-r--r--include/net/mac80211.h6
-rw-r--r--net/mac80211/main.c2
2 files changed, 8 insertions, 0 deletions
diff --git a/include/net/mac80211.h b/include/net/mac80211.h
index c39ed0792948..a2bd2f98b63f 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 19fbd25a705b..2dfe1768e2ab 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));