From: Hannes Reinecke <hare@suse.de>
To: Christoph Hellwig <hch@infradead.org>
Cc: Webb Scales <webbnh@hp.com>,
James Bottomley <jbottomley@parallels.com>,
linux-scsi@vger.kernel.org
Subject: Re: [PATCH] megaraid_sas: Enable shared tag map
Date: Thu, 02 Oct 2014 11:50:42 +0200 [thread overview]
Message-ID: <542D1FF2.1010307@suse.de> (raw)
In-Reply-To: <20141002091916.GA13227@infradead.org>
On 10/02/2014 11:19 AM, Christoph Hellwig wrote:
> On Thu, Oct 02, 2014 at 08:51:20AM +0200, Hannes Reinecke wrote:
>>
>> I'm afraid it's not _that_ easy.
>> SCSI-II tagged queueing has some specific tag values:
>>
>> #define SIMPLE_QUEUE_TAG 0x20
>> #define HEAD_OF_QUEUE_TAG 0x21
>> #define ORDERED_QUEUE_TAG 0x22
>
> These are not tag values. These are message codes set in the first byte
> of the Queue tag message, the second byte is the actual tag.
>
>> The recommendation here is to use 'scmd->request->tag' whenever
>> you want to get to the tag number, and 'scmd->tag' if you have to
>> play around with SCSI-II TCQ.
>> But if not I would strongly advise to leave 'scmd->tag' alone.
>
> Or kill off scmd->tag.. Let's see how feasible that is.
>
I'm about to.
(See my last two patches).
There are now two instances left:
NCR5380 (and derived LLDDs) and fnic.
For some weird reasons fnic decided to duplicate blk-tag
functionality. Looking into it.
And NCR5380 tag support can be safely ignored, it never worked anyway.
Cheers,
Hannes
--
Dr. Hannes Reinecke zSeries & Storage
hare@suse.de +49 911 74053 688
SUSE LINUX Products GmbH, Maxfeldstr. 5, 90409 Nürnberg
GF: J. Hawn, J. Guild, F. Imendörffer, HRB 16746 (AG Nürnberg)
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next prev parent reply other threads:[~2014-10-02 9:50 UTC|newest]
Thread overview: 16+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-09-29 11:47 [PATCH] megaraid_sas: Enable shared tag map Hannes Reinecke
2014-09-29 16:52 ` Webb Scales
2014-09-29 17:08 ` James Bottomley
2014-09-30 7:43 ` Christoph Hellwig
2014-09-30 9:08 ` Hannes Reinecke
2014-10-01 18:51 ` Webb Scales
2014-10-01 21:10 ` Christoph Hellwig
2014-10-02 6:51 ` Hannes Reinecke
2014-10-02 9:19 ` Christoph Hellwig
2014-10-02 9:50 ` Hannes Reinecke [this message]
2014-10-02 11:36 ` Christoph Hellwig
2014-10-02 12:00 ` Hannes Reinecke
2014-10-02 14:32 ` Christoph Hellwig
2014-10-02 12:05 ` James Bottomley
2014-10-02 12:14 ` Hannes Reinecke
2014-10-02 13:06 ` James Bottomley
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