From: hch@lst.de (Christoph Hellwig)
Subject: [PATCH] nvme: support bi-directional commands
Date: Wed, 7 Dec 2016 18:44:27 +0100 [thread overview]
Message-ID: <20161207174427.GA25211@lst.de> (raw)
In-Reply-To: <20161207175049.GD29574@localhost.localdomain>
On Wed, Dec 07, 2016@12:50:50PM -0500, Keith Busch wrote:
> NVMe defines this capability, so why would we want to make it unreachable
> in Linux?
NVMe defines no user of it, so that defintion is entirely theoretical
and it's a giant mess, and your implementation does not actually work
for the general case.
> SG_DXFER_TO_FROM_DEV does bidi commands in one request for
> SCSI using the same rq_map_data method this patch proposes to use.
SG_DXFER_TO_FROM_DEV does not actually work, for SCSI bidi support
you need bsg with the crazy next_rq linked block layer bidi support.
next prev parent reply other threads:[~2016-12-07 17:44 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-12-07 17:39 [PATCH] nvme: support bi-directional commands Keith Busch
2016-12-07 17:33 ` Christoph Hellwig
2016-12-07 17:50 ` Keith Busch
2016-12-07 17:44 ` Christoph Hellwig [this message]
2016-12-07 18:07 ` Keith Busch
2016-12-07 17:59 ` Christoph Hellwig
2016-12-07 18:15 ` Keith Busch
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