mac80211: fix fast_tx header alignment

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")
Cc: stable@vger.kernel.org
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/sta_info.h b/net/mac80211/sta_info.h
index c8b8ccc..78b0ef3 100644 (file)
--- a/net/mac80211/sta_info.h
+++ b/net/mac80211/sta_info.h
@@ -280,7 +280,7 @@ 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;
 };