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Subject: Re: [PATCH]: jiffies wrap in ll_rw_blk.c
From: Alan Cox <alan@lxorguk.ukuu.org.uk>
To: Luben Tuikov <luben@splentec.com>
Cc: Linux Kernel Mailing List <linux-kernel@vger.kernel.org>, axboe@suse.de
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Date: 20 Nov 2002 21:19:33 +0000
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On Wed, 2002-11-20 at 20:44, Luben Tuikov wrote:
> --- ll_rw_blk.c.old     Wed Nov 20 15:32:50 2002
> +++ ll_rw_blk.c Wed Nov 20 15:33:06 2002
> @@ -2092,7 +2092,7 @@
>                 complete(req->waiting);
>  
>         if (disk) {
> -               unsigned long duration = jiffies - req->start_time;
> +               unsigned long duration = (signed) jiffies - (signed) req->start_time;
>                 switch (rq_data_dir(req)) {

It was right before. Your patch breaks it. Think about it in unsigned
maths

              0x00000002 - 0xFFFFFFFF = 0x00000003

Alan

-
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