Messages in this thread | | | Date | Wed, 26 Dec 2007 11:58:56 -0800 | From | "Ray Lee" <> | Subject | Re: [PATCH 1/4] fs/autofs: Use time_before, time_before_eq, etc. |
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On Dec 26, 2007 7:21 AM, Julia Lawall <julia@diku.dk> wrote: > - if (jiffies - ent->last_usage < timeout) > + if (time_before(jiffies, ent->last_usage + timeout))
I don't think this is a safe change? subtraction is always safe (if you think about it as 'distance'), addition isn't always safe unless you know the range. The time_before macro will expand that out to (effectively):
if ( (long)(ent->last_usage + timeout) - (long)(jiffies) < 0 )
which seems to introduce an overflow condition in the first term.
Dunno, I may be wrong (happens often), but at the very least what you've transformed it into is no longer obviously correct, and so it's not a great change.
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