[063/200] mac80211: fix rts threshold check

[Greg KH]

2.6.34-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Shanyu Zhao <shanyu.zhao@xxxxxxxxx>

commit a2c40249a36d0b4d76d1caf6bf806e4ae5b06e8a upstream.

Currently whenever rts thresold is set, every packet will use RTS
protection no matter its size exceeds the threshold or not. This is
due to a bug in the rts threshold check.
	if (len > tx->local->hw.wiphy->rts_threshold) {
		txrc.rts = rts = true;
	}
Basically it is comparing an int (len) and a u32 (rts_threshold),
and the variable len is assigned as:
	len = min_t(int, tx->skb->len + FCS_LEN,
			 tx->local->hw.wiphy->frag_threshold);
However, when frag_threshold is "-1", len is always "-1", which is
0xffffffff therefore rts is always set to true.

Signed-off-by: Shanyu Zhao <shanyu.zhao@xxxxxxxxx>
Reviewed-by: Johannes Berg <johannes@xxxxxxxxxxxxxxxx>
Signed-off-by: John W. Linville <linville@xxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
 net/mac80211/tx.c |    5 +++--
 1 file changed, 3 insertions(+), 2 deletions(-)

--- a/net/mac80211/tx.c
+++ b/net/mac80211/tx.c
@@ -584,7 +584,8 @@ ieee80211_tx_h_rate_ctrl(struct ieee8021
 	struct ieee80211_hdr *hdr = (void *)tx->skb->data;
 	struct ieee80211_supported_band *sband;
 	struct ieee80211_rate *rate;
-	int i, len;
+	int i;
+	u32 len;
 	bool inval = false, rts = false, short_preamble = false;
 	struct ieee80211_tx_rate_control txrc;
 	u32 sta_flags;
@@ -593,7 +594,7 @@ ieee80211_tx_h_rate_ctrl(struct ieee8021
 
 	sband = tx->local->hw.wiphy->bands[tx->channel->band];
 
-	len = min_t(int, tx->skb->len + FCS_LEN,
+	len = min_t(u32, tx->skb->len + FCS_LEN,
 			 tx->local->hw.wiphy->frag_threshold);
 
 	/* set up the tx rate control struct we give the RC algo */


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