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From: Christoph Hellwig <hch@infradead.org>
To: "Nicholas A. Bellinger" <nab@linux-iscsi.org>
Cc: Christoph Hellwig <hch@infradead.org>,
	"Nicholas A. Bellinger" <nab@daterainc.com>,
	target-devel <target-devel@vger.kernel.org>,
	lkml <linux-kernel@vger.kernel.org>,
	linux-scsi <linux-scsi@vger.kernel.org>,
	Christoph Hellwig <hch@lst.de>, Hannes Reinecke <hare@suse.de>,
	Martin Petersen <martin.petersen@oracle.com>,
	Chris Mason <chris.mason@fusionio.com>,
	James Bottomley <JBottomley@Parallels.com>,
	Giridhar Malavali <giridhar.malavali@qlogic.com>,
	Chad Dupuis <chad.dupuis@qlogic.com>
Subject: Re: [PATCH 9/9] tcm_qla2xxx: Add special case for COMPARE_AND_WRITE data_direction
Date: Wed, 21 Aug 2013 09:04:50 -0700	[thread overview]
Message-ID: <20130821160450.GA30848@infradead.org> (raw)
In-Reply-To: <1377070267.32763.26.camel@haakon3.risingtidesystems.com>

On Wed, Aug 21, 2013 at 12:31:07AM -0700, Nicholas A. Bellinger wrote:
> Is it really worth having two se_cmd_flags for COMPARE_AND_WRITE..?

Not leaking the abstraction into the driver is always worth the effort.

But looking at the other patches I haven't reviewed yet I think the
issue is more severe anyway, see my next reply.

> > Also it might make sense to lift this helper to get a dma direction from
> > a command into common code.
> > 
> 
> Mmm, perhaps.  I don't recall of the top of my head why tcm_qla2xxx
> actually needed to reverse it's dma direction (I'm sure that Roland
> knows, CC'ed), but IIRC it was a tcm_qla2xxx specific thing..?

It's the same issue for any hardware driver that directly maps a
se_cmd - the direction the target expects is reversed to what the
driver expects, in addition any BIDI or other special meanings will
need handling.


  reply	other threads:[~2013-08-21 16:04 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-08-20 20:07 [PATCH 0/9] target: Add support for COMPARE_AND_WRITE (VAAI) emulation Nicholas A. Bellinger
2013-08-20 20:07 ` [PATCH 1/9] scsi: Add CDB definition for COMPARE_AND_WRITE Nicholas A. Bellinger
2013-08-21  6:30   ` Christoph Hellwig
2013-08-20 20:07 ` [PATCH 2/9] target: Add return for se_cmd->transport_complete_callback Nicholas A. Bellinger
2013-08-20 20:07 ` [PATCH 3/9] target: Add memory allocation for bidirectional commands Nicholas A. Bellinger
2013-08-20 20:07 ` [PATCH 4/9] target: Add TCM_MISCOMPARE_VERIFY sense handling Nicholas A. Bellinger
2013-08-20 20:07 ` [PATCH 5/9] target: Skip ->queue_data_in() callbacks for COMPARE_AND_WRITE Nicholas A. Bellinger
2013-08-21  6:32   ` Christoph Hellwig
2013-08-21  7:20     ` Nicholas A. Bellinger
2013-08-20 20:07 ` [PATCH 6/9] target: Allow sbc_ops->execute_rw() to accept SGLs + data_direction Nicholas A. Bellinger
2013-08-21  6:35   ` Christoph Hellwig
2013-08-21  7:26     ` Nicholas A. Bellinger
2013-08-20 20:07 ` [PATCH 7/9] target: Add transport_reset_sgl_orig() for COMPARE_AND_WRITE Nicholas A. Bellinger
2013-08-20 20:07 ` [PATCH 8/9] target: Add support for COMPARE_AND_WRITE emulation Nicholas A. Bellinger
2013-08-21 16:14   ` Christoph Hellwig
2013-08-21 17:47     ` Nicholas A. Bellinger
2013-08-20 20:08 ` [PATCH 9/9] tcm_qla2xxx: Add special case for COMPARE_AND_WRITE data_direction Nicholas A. Bellinger
2013-08-21  6:37   ` Christoph Hellwig
2013-08-21  7:31     ` Nicholas A. Bellinger
2013-08-21 16:04       ` Christoph Hellwig [this message]
2013-08-21 14:38   ` Roland Dreier
2013-08-21 15:53     ` Christoph Hellwig
2013-08-21 17:52       ` Nicholas A. Bellinger
2013-08-21 16:47     ` Roland Dreier
2013-08-20 21:29 ` [PATCH 0/9] target: Add support for COMPARE_AND_WRITE (VAAI) emulation Christoph Hellwig
2013-08-20 21:53   ` Nicholas A. Bellinger
2013-08-20 22:01     ` Douglas Gilbert
2013-08-20 22:19       ` Nicholas A. Bellinger

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