Date: Mon, 11 Jan 1999 15:10:14 -0800 (PST) From: Matthew Jacob <mjacob@feral.com> To: Julian Elischer <julian@whistle.com> Cc: freebsd-hackers@FreeBSD.ORG Subject: Re: what is the meaning of this useless code? Message-ID: <Pine.LNX.4.04.9901111508370.18573-100000@feral-gw> In-Reply-To: <Pine.BSF.3.95.990111145306.395B-100000@current1.whistle.com>
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On Mon, 11 Jan 1999, Julian Elischer wrote: > > > On Mon, 11 Jan 1999, Matthew Jacob wrote: > > > > > if (resid > maxio) > > resid = maxio; > > > > return getpbuf(); > > } > > > > > > why is resid being truyncaated and maxio being set when this has no > > effect? > > I think resid was originally an agument to getpbuf > but mechanical edits have turned it all into a NOP. > Good catch.. Okay. > > However there is a related problem.. > > the maximum IO size allowed for a device is kept in the > cdevsw entry, which is the WRONG place, because > it cannot correctly reflect the case when there are two differnt devices > with different limits on the same controller (e.g. two different drives > or even two differend controllers on one driver). > Well, there are a number of limits- some are device specific, some are bus specific and some are VM/OS specific. It's a bit confusing which applies here. I'm going to ponder this as time permits. I'm trying to track down a hang on alpha with larget I/Os and this led me to try and follow the raw I/O path which led to this... To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-hackers" in the body of the message
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