Messages in this thread | | | Date | Fri, 18 Apr 2008 23:31:29 +0530 | From | "pradeep singh rautela" <> | Subject | Re: [PATCH 5/5] tun: vringfd xmit support. |
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On Fri, Apr 18, 2008 at 7:55 PM, Ray Lee <ray-lk@madrabbit.org> wrote: > On Fri, Apr 18, 2008 at 4:46 AM, pradeep singh rautela > <rautelap@gmail.com> wrote: > > > > On Fri, Apr 18, 2008 at 10:13 AM, Rusty Russell <rusty@rustcorp.com.au> wrote: > > > > + /* How many pages will this take? */ > > > + npages = 1 + (base + len - 1)/PAGE_SIZE - base/PAGE_SIZE; > > > > Hi Rusty, > > A trivial suggestion, how about > > npages = 1+(len -1)/PAGE_SIZE ? > > That's not the same. In particular, his version accounts for the > fractional page at the beginning, while yours doesn't.
Oh thanks for correcting me Ray. :) > > While it's tempting to use algebra to simplify things, it's not safe > to do so when the expression involves division over the integers. The > only care-free integer math in a computer is subtraction and ++.
I stand corrected.
Sorry for noise.
Thanks, -- Pradeep Singh Rautela http://eagain.wordpress.com http://emptydomain.googlepages.com
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