From: Christoph Hellwig <hch@infradead.org>
To: Hannes Reinecke <hare@suse.de>
Cc: Christoph Hellwig <hch@infradead.org>,
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, 2 Oct 2014 02:19:16 -0700 [thread overview]
Message-ID: <20141002091916.GA13227@infradead.org> (raw)
In-Reply-To: <542CF5E8.3030601@suse.de>
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.
next prev parent reply other threads:[~2014-10-02 9:19 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 [this message]
2014-10-02 9:50 ` Hannes Reinecke
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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