mac80211: correct fragmentation threshold check

The fragmentation threshold is defined to be including the
FCS, and the code that sets the TX_FRAGMENTED flag correctly
accounts for those four bytes. The code that verifies this
doesn't though, which could lead to spurious warnings and
frames being dropped although everything is ok. Correct the
code by accounting for the FCS.

(JWL -- The problem is described here:
 http://article.gmane.org/gmane.linux.kernel.wireless.general/32205 )

Signed-off-by: Johannes Berg <johannes@sipsolutions.net>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

diff --git a/net/mac80211/tx.c b/net/mac80211/tx.c
index 3fb04a86444d959d980f5e7d3e0ce1a2c779a63a..63656266d567e50f5b2d82bc4580d7abdfbf65b4 100644 (file)
--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -772,7 +772,7 @@ ieee80211_tx_h_fragment(struct ieee80211_tx_data *tx)
        hdrlen = ieee80211_hdrlen(hdr->frame_control);
 
        /* internal error, why is TX_FRAGMENTED set? */
-       if (WARN_ON(skb->len <= frag_threshold))
+       if (WARN_ON(skb->len + FCS_LEN <= frag_threshold))
                return TX_DROP;
 
        /*