tx4938ide: Avoid underflow on calculation of a wait cycle
Make 'wt' variable signed while it can be negative during calculation.
Suggested-by: Sergei Shtylyov <sshtylyov@ru.mvista.com>
Signed-off-by: Atsushi Nemoto <anemo@mba.ocn.ne.jp>
Cc: sshtylyov@ru.mvista.com
Signed-off-by: Bartlomiej Zolnierkiewicz <bzolnier@gmail.com>
diff --git a/drivers/ide/tx4938ide.c b/drivers/ide/tx4938ide.c
index 796289c..9120063 100644
--- a/drivers/ide/tx4938ide.c
+++ b/drivers/ide/tx4938ide.c
@@ -26,12 +26,13 @@
unsigned int sp = (cr >> 4) & 3;
unsigned int clock = gbus_clock / (4 - sp);
unsigned int cycle = 1000000000 / clock;
- unsigned int wt, shwt;
+ unsigned int shwt;
+ int wt;
/* Minimum DIOx- active time */
wt = DIV_ROUND_UP(t->act8b, cycle) - 2;
/* IORDY setup time: 35ns */
- wt = max(wt, DIV_ROUND_UP(35, cycle));
+ wt = max_t(int, wt, DIV_ROUND_UP(35, cycle));
/* actual wait-cycle is max(wt & ~1, 1) */
if (wt > 2 && (wt & 1))
wt++;
