From: Felix Fietkau <nbd@nbd.name>
Date: Thu, 19 May 2016 15:34:38 +0000 (+0200)
Subject: mac80211: fix fast_tx header alignment
X-Git-Tag: v4.6.5~202
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=84119a97162460f5ff796ada1756abab8dba187b;p=thirdparty%2Fkernel%2Fstable.git

mac80211: fix fast_tx header alignment

commit 6fe04128f158c5ad27e7504bfdf1b12e63331bc9 upstream.

The header field is defined as u8[] but also accessed as struct
ieee80211_hdr. Enforce an alignment of 2 to prevent unnecessary
unaligned accesses, which can be very harmful for performance on many
platforms.

Fixes: e495c24731a2 ("mac80211: extend fast-xmit for more ciphers")
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---

diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index 62193f4bc37bb..ba7ce53ec6153 100644
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -275,7 +275,7 @@ struct ieee80211_fast_tx {
 	u8 sa_offs, da_offs, pn_offs;
 	u8 band;
 	u8 hdr[30 + 2 + IEEE80211_FAST_XMIT_MAX_IV +
-	       sizeof(rfc1042_header)];
+	       sizeof(rfc1042_header)] __aligned(2);
 
 	struct rcu_head rcu_head;
 };