mac80211: Build TX radiotap header dynamically

Get rid of the ieee80211_tx_status_rtap_hdr struct and instead build the
rtap header dynamically. This makes it easier to extend the rtap header
generation in the future.

Add ieee80211_tx_radiotap_len to calculate the expected size of the
rtap header before generating it. Since we can't check if the rtap
header fits into the requested headroom during compile time anymore
add a WARN_ON_ONCE.

Also move the actual rtap header generation into its own function.

Signed-off-by: Helmut Schaa <helmut.schaa@googlemail.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 1 insertions, 5 deletions

diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 17b038aeac9b..d4ee6d234a78 100644
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -904,12 +904,8 @@ 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.
          */
-#ifndef __CHECKER__
-        BUILD_BUG_ON(IEEE80211_TX_STATUS_HEADROOM !=
-                        sizeof(struct ieee80211_tx_status_rtap_hdr));
-#endif
         local->tx_headroom = max_t(unsigned int , local->hw.extra_tx_headroom,
-                                   sizeof(struct ieee80211_tx_status_rtap_hdr));
+                                   IEEE80211_TX_STATUS_HEADROOM);
 
         debugfs_hw_add(local);