From mboxrd@z Thu Jan  1 00:00:00 1970
From: malahal@us.ibm.com
Subject: Re: [PATCH] gdth: scp timeout clean up (try #2)
Date: Tue, 13 Nov 2007 18:39:29 -0800
Message-ID: <20071114023929.GB29136@us.ibm.com>
References: <20071106065439.GA30397@us.ibm.com> <47301DA7.8000202@panasas.com> <20071106223453.GA5668@us.ibm.com> <20071107132256.GG5525@kernel.dk>
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In-Reply-To: <20071107132256.GG5525@kernel.dk>
Sender: linux-scsi-owner@vger.kernel.org
List-Id: linux-scsi@vger.kernel.org
To: Jens Axboe <jens.axboe@oracle.com>
Cc: Boaz Harrosh <bharrosh@panasas.com>, linux-scsi@vger.kernel.org, Achim_Leubner@adaptec.com

Jens Axboe [jens.axboe@oracle.com] wrote:
> +static void blk_rq_timed_out_timer(unsigned long data)
> +{
> +	struct request_queue *q = (struct request_queue *) data;
> +	unsigned long flags, next = 0;
> +	struct request *rq, *tmp;
> +
> +	spin_lock_irqsave(q->queue_lock, flags);
> +
> +	list_for_each_entry_safe(rq, tmp, &q->timeout_list, timeout_list) {
> +		if (!next || time_before(next, rq->timeout))
> +			next = rq->timeout;
> +		if (time_after_eq(jiffies, rq->timeout)) {
> +			list_del_init(&rq->timeout_list);
> +			blk_rq_timed_out(rq);
> +		}
> +	}
> +
> +	if (next)
> +		mod_timer(&q->timeout, round_jiffies(next));
> +
> +	spin_unlock_irqrestore(q->queue_lock, flags);
> +}

Is it possible that an rq->timeout could be zero, after all it is
jiffies? If so, the code may fail to schedule a timeout in such a case.