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From: Marta Rybczynska <mrybczyn@kalray.eu>
To: Christoph Hellwig <hch@lst.de>
Cc: Charles Machalow <csm10495@gmail.com>,
	linux-nvme <linux-nvme@lists.infradead.org>,
	kbusch <kbusch@kernel.org>, axboe <axboe@fb.com>,
	Sagi Grimberg <sagi@grimberg.me>,
	linux-kernel <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] nvme: change nvme_passthru_cmd64's result field.
Date: Mon, 4 Nov 2019 15:34:40 +0100 (CET)	[thread overview]
Message-ID: <1977598237.90293761.1572878080625.JavaMail.zimbra@kalray.eu> (raw)
In-Reply-To: <20191031133921.GA4763@lst.de>



----- On 31 Oct, 2019, at 14:39, Christoph Hellwig hch@lst.de wrote:

> On Wed, Oct 30, 2019 at 10:03:38PM -0700, Charles Machalow wrote:
>> Changing nvme_passthru_cmd64's result field to be backwards compatible
>> with the nvme_passthru_cmd/nvme_admin_cmd struct in terms of the result
>> field. With this change the first 32 bits of result in either case
>> point to CQE DW0. This allows userspace tools to use the new structure
>> when using the old ADMIN/IO_CMD ioctls or new ADMIN/IO_CMD64 ioctls.
> 
> All that casting is a pretty bad idea.  please just add an explicit
> reserved field before the result, and check that it always is zero
> in the ioctl handler.

That would change the size of a structure in UAPI, won't it? 
I wanted to avoid it when adding the *64 ioctls and that's why
I added separate ones instead of extending the ones that exist.

Marta

  parent reply	other threads:[~2019-11-04 14:34 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-10-31  5:03 [PATCH] nvme: change nvme_passthru_cmd64's result field Charles Machalow
2019-10-31 13:39 ` Christoph Hellwig
     [not found]   ` <CANSCoS8rN6g7u6iG4SRTcXjdj68cbimvX1n1Ex+FBAkhAAivJA@mail.gmail.com>
2019-10-31 13:59     ` Christoph Hellwig
2019-10-31 15:39       ` Charles Machalow
2019-10-31 13:59   ` Charles Machalow
2019-11-04 14:34   ` Marta Rybczynska [this message]
2019-11-04 14:51     ` Charles Machalow
2019-11-04 14:56       ` Marta Rybczynska
2019-11-04 15:01         ` Keith Busch
2019-11-04 15:29           ` Christoph Hellwig
2019-11-04 15:32             ` Keith Busch
2019-11-04 15:01         ` Charles Machalow
2019-11-04 15:16           ` Marta Rybczynska
2019-11-04 15:20             ` Charles Machalow
2019-11-04 15:30               ` Christoph Hellwig

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