RE: [PATCH 21/38] mwifiex: fix comparison expression

From: Andrzej Hajda [mailto:a.hajda@samsung.com]
Sent: Monday, September 21, 2015 7:04 PM
To: linux-kernel@vger.kernel.org
Cc: Andrzej Hajda; Bartlomiej Zolnierkiewicz; Marek Szyprowski;
Amitkumar Karwar; Nishant Sarmukadam; Kalle Valo; linux-
wireless@vger.kernel.org; netdev@vger.kernel.org
Subject: [PATCH 21/38] mwifiex: fix comparison expression

To avoid underflows signed variables should be used in expression.

The problem has been detected using proposed semantic patch
scripts/coccinelle/tests/unsigned_lesser_than_zero.cocci [1].

[1]: http://permalink.gmane.org/gmane.linux.kernel/2038576

Signed-off-by: Andrzej Hajda <redacted>
---
 drivers/net/wireless/mwifiex/11n_rxreorder.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/net/wireless/mwifiex/11n_rxreorder.c

b/drivers/net/wireless/mwifiex/11n_rxreorder.c
index 2906cd5..b3970a8 100644

--- a/drivers/net/wireless/mwifiex/11n_rxreorder.c
+++ b/drivers/net/wireless/mwifiex/11n_rxreorder.c

@@ -615,10 +615,10 @@ int mwifiex_11n_rx_reorder_pkt(struct

mwifiex_private *priv,
 	    ((end_win > start_win) && ((seq_num > end_win) ||
 				       (seq_num < start_win)))) {
 		end_win = seq_num;
-		if (((seq_num - win_size) + 1) >= 0)
+		if (((end_win - win_size) + 1) >= 0)
 			start_win = (end_win - win_size) + 1;
 		else
-			start_win = (MAX_TID_VALUE - (win_size - seq_num)) +
1;
+			start_win = (MAX_TID_VALUE - (win_size - end_win)) +
1;
 		mwifiex_11n_dispatch_pkt_until_start_win(priv, tbl,
start_win);
 	}