From: Andrzej Hajda Date: Mon, 21 Sep 2015 13:33:49 +0000 (+0200) Subject: isdn: hisax: fix frame calculation X-Git-Tag: v4.9.8~3303^2~301 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=8f89642fa10bb6ec02feaa8e3d1d62df671d0207;p=platform%2Fkernel%2Flinux-rpi3.git isdn: hisax: fix frame calculation Difference of unsigned values is also unsigned so it does not make sense to check its sign. 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 Signed-off-by: David S. Miller --- diff --git a/drivers/isdn/hisax/hfc4s8s_l1.c b/drivers/isdn/hisax/hfc4s8s_l1.c index 0e5d673..9600cd7 100644 --- a/drivers/isdn/hisax/hfc4s8s_l1.c +++ b/drivers/isdn/hisax/hfc4s8s_l1.c @@ -646,14 +646,14 @@ rx_d_frame(struct hfc4s8s_l1 *l1p, int ech) f1 = Read_hfc8_stable(l1p->hw, A_F1); f2 = Read_hfc8(l1p->hw, A_F2); - df = f1 - f2; - if ((f1 - f2) < 0) - df = f1 - f2 + MAX_F_CNT + 1; + if (f1 < f2) + df = MAX_F_CNT + 1 + f1 - f2; + else + df = f1 - f2; - if (!df) { + if (!df) return; /* no complete frame in fifo */ - } z1 = Read_hfc16_stable(l1p->hw, A_Z1); z2 = Read_hfc16(l1p->hw, A_Z2);