linux-kernel - [patch] hangcheck-timer: cleanup casting in hangcheck

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Message-ID: <20141029084250.GA8939@mwanda>
Date:	Wed, 29 Oct 2014 11:42:50 +0300
From:	Dan Carpenter <dan.carpenter@...cle.com>
To:	Arnd Bergmann <arnd@...db.de>
Cc:	Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
	linux-kernel@...r.kernel.org, kernel-janitors@...r.kernel.org
Subject: [patch] hangcheck-timer: cleanup casting in hangcheck_init()

The 32 bit addition "(hangcheck_margin + hangcheck_tick)" could
potentially overflow.  It triggers a static checker warning to have an
overflowed addition followed by a no-op cast.  I have moved the cast so
that the addition can't overflow.

Also I removed the unneeded cast on the following line since both
"hangcheck_tsc_margin" and "TIMER_FREQ" are already 64 bit types.

Signed-off-by: Dan Carpenter <dan.carpenter@...cle.com>

diff --git a/drivers/char/hangcheck-timer.c b/drivers/char/hangcheck-timer.c
index ebc4c73..a7c5c59 100644
--- a/drivers/char/hangcheck-timer.c
+++ b/drivers/char/hangcheck-timer.c
@@ -168,8 +168,8 @@ static int __init hangcheck_init(void)
 	printk("Hangcheck: starting hangcheck timer %s (tick is %d seconds, margin is %d seconds).\n",
 	       VERSION_STR, hangcheck_tick, hangcheck_margin);
 	hangcheck_tsc_margin =
-		(unsigned long long)(hangcheck_margin + hangcheck_tick);
-	hangcheck_tsc_margin *= (unsigned long long)TIMER_FREQ;
+		(unsigned long long)hangcheck_margin + hangcheck_tick;
+	hangcheck_tsc_margin *= TIMER_FREQ;
 
 	hangcheck_tsc = ktime_get_ns();
 	mod_timer(&hangcheck_ticktock, jiffies + (hangcheck_tick*HZ));
--
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