linux-kernel - Re: [PATCH] fix msecs_to_jiffies() to not return values greater than MAX_JIFFY

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Message-Id: <6206394.oTpczxkaEM@donald.sf-tec.de>
Date:	Tue, 29 Mar 2011 23:03:47 +0200
From:	Rolf Eike Beer <eike-kernel@...tec.de>
To:	Thomas Gleixner <tglx@...utronix.de>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	John Stultz <johnstul@...ibm.com>,
	"H. Peter Anvin" <hpa@...or.com>
Subject: Re: [PATCH] fix msecs_to_jiffies() to not return values greater than MAX_JIFFY_OFFSET

Am Dienstag, 29. M�rz 2011, 21:42:59 schrieb Thomas Gleixner:
> On Tue, 29 Mar 2011, Rolf Eike Beer wrote:

> > @@ -467,9 +468,10 @@ unsigned long msecs_to_jiffies(const unsigned int m)
> > 
> >  	if (HZ > MSEC_PER_SEC && m > jiffies_to_msecs(MAX_JIFFY_OFFSET))
> >  	
> >  		return MAX_JIFFY_OFFSET;
> 
> Hmm, this check is silly. MUL32 is chosen, so that we cannot overflow.

IMHO the second part of the check should be enough, no? If m is greater than 
j2m(MAX) then it's irrelevant what's up else, it's too big. Period.

Eike
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