From: Felix Fietkau <nbd@nbd.name>
Date: Fri, 9 Feb 2018 19:46:54 +0100
Subject: [PATCH] mac80211: round IEEE80211_TX_STATUS_HEADROOM up to multiple
 of 4

This ensures that mac80211 allocated management frames are properly
aligned, which makes copying them more efficient.
For instance, mt76 uses iowrite32_copy to copy beacon frames to beacon
template memory on the chip.
Misaligned 32-bit accesses cause CPU exceptions on MIPS and should be
avoided.

Signed-off-by: Felix Fietkau <nbd@nbd.name>
---

--- a/include/net/mac80211.h
+++ b/include/net/mac80211.h
@@ -4145,7 +4145,7 @@ void ieee80211_sta_uapsd_trigger(struct
  * The TX headroom reserved by mac80211 for its own tx_status functions.
  * This is enough for the radiotap header.
  */
-#define IEEE80211_TX_STATUS_HEADROOM	14
+#define IEEE80211_TX_STATUS_HEADROOM	ALIGN(14, 4)
 
 /**
  * ieee80211_sta_set_buffered - inform mac80211 about driver-buffered frames