From mboxrd@z Thu Jan  1 00:00:00 1970
From: hch@lst.de (Christoph Hellwig)
Date: Mon, 21 Mar 2016 16:57:36 +0100
Subject: [PATCH RFC] nvme: rewrite discard support
In-Reply-To: <20160321155138.GA19307@localhost.localdomain>
References: <1458170132-16031-1-git-send-email-mlin@kernel.org>
 <20160317153335.GB6217@localhost.lm.intel.com>
 <20160321144759.GA12934@lst.de>
 <20160321155138.GA19307@localhost.localdomain>
Message-ID: <20160321155736.GA14643@lst.de>

On Mon, Mar 21, 2016@03:51:39PM +0000, Keith Busch wrote:
> It looks like SCSI's special handling lead to what the code comments
> describe as a "horrible hack", so that's not convincing this is a good
> example to follow.

Nah, the "horrible hack" is adding a payload to the request.  We went
over and over this and everyone but Kent agrees it's the least horrible
option to handle discards in generic code.  NVMe side steps this a bit
by not trying to handle this in common code, but that only works as
long as it's a single tightly integrated driver, not for a layer
architecture like SCSI, or what NVMe is increasingly moving to.