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From: Charles Machalow <csm10495@gmail.com>
To: Marta Rybczynska <mrybczyn@kalray.eu>
Cc: Christoph Hellwig <hch@lst.de>,
	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 06:51:08 -0800	[thread overview]
Message-ID: <CANSCoS-2k08Si3a4b+h-4QTR86EfZHZx_oaGAHWorsYkdp35Bg@mail.gmail.com> (raw)
In-Reply-To: <1977598237.90293761.1572878080625.JavaMail.zimbra@kalray.eu>

For this one yes, UAPI size changes. Though I believe this IOCTL
hasn't been in a released Kernel yet (just RC). Technically it may be
changeable as a fix until the next Kernel is released. I do think its
a useful enough
change to warrant a late fix.

- Charlie Scott Machalow

On Mon, Nov 4, 2019 at 6:34 AM Marta Rybczynska <mrybczyn@kalray.eu> wrote:
>
>
>
> ----- 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

  reply	other threads:[~2019-11-04 14:51 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
2019-11-04 14:51     ` Charles Machalow [this message]
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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