Re: [PATCH]: jiffies wrap in ll_rw_blk.c

Alan Cox (alan@lxorguk.ukuu.org.uk)
20 Nov 2002 21:19:33 +0000


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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