From: Johannes Thumshirn <jthumshirn@suse.de>
To: Bart Van Assche <Bart.VanAssche@sandisk.com>
Cc: "Martin K . Petersen" <martin.petersen@oracle.com>,
James Bottomley <jejb@linux.vnet.ibm.com>,
Hannes Reinecke <hare@suse.de>,
Christoph Hellwig <hch@infradead.org>,
Linux SCSI Mailinglist <linux-scsi@vger.kernel.org>,
Linux Kernel Mailinglist <linux-kernel@vger.kernel.org>,
Arnd Bergmann <arnd@arndb.de>
Subject: Re: [PATCH] libfc: fix seconds_since_last_reset miscalculation
Date: Tue, 15 Nov 2016 10:18:40 +0100 [thread overview]
Message-ID: <20161115091840.7cldqui4dpi7nrz5@linux-x5ow.site> (raw)
In-Reply-To: <BLUPR02MB16830DECB29262BACBA94FA681A60@BLUPR02MB1683.namprd02.prod.outlook.com>
On Tue, Nov 08, 2016 at 03:04:43PM +0000, Bart Van Assche wrote:
[...]
> Hello Johannes,
>
> I think the above code will miscalculate seconds_since_last_reset if
> 'jiffies' wraps around after an lport has been created and before
> seconds_since_last_reset is computed. Shouldn't seconds_since_last_reset
> be computed as follows?
>
> fc_stats->seconds_since_last_reset = (jiffies - boot_time) / HZ;
But what happens when jiffies - boot_time becomes negative? Then we
reintroduce the bug again and have 'fcoeadm -s' show weird values.
Byte,
Johannes
--
Johannes Thumshirn Storage
jthumshirn@suse.de +49 911 74053 689
SUSE LINUX GmbH, Maxfeldstr. 5, 90409 Nürnberg
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next prev parent reply other threads:[~2016-11-15 9:18 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-11-08 8:44 [PATCH] libfc: fix seconds_since_last_reset miscalculation Johannes Thumshirn
2016-11-08 15:04 ` Bart Van Assche
2016-11-15 9:18 ` Johannes Thumshirn [this message]
2016-11-15 14:50 ` Bart Van Assche
2016-11-15 15:05 ` Johannes Thumshirn
2016-11-16 16:58 ` Arnd Bergmann
2016-11-17 8:12 ` Johannes Thumshirn
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