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From:   Charles Machalow <csm10495@gmail.com>
Date:   Mon, 4 Nov 2019 07:20:43 -0800
Message-ID: <CANSCoS9A1XY4DzdBwGU4+oT-uKvpohxhyWxdJ1ySJ6QKv6moKw@mail.gmail.com>
Subject: Re: [PATCH] nvme: change nvme_passthru_cmd64's result field.
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>
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The thing with that structure is if you use it with the old IOCTL, the
result will go into rsvd2 instead of the first 32 bits of result.

- Charlie Scott Machalow

On Mon, Nov 4, 2019 at 7:16 AM Marta Rybczynska <mrybczyn@kalray.eu> wrote:
>
>
>
> ----- On 4 Nov, 2019, at 16:01, Charles Machalow csm10495@gmail.com wrote:
>
> > Yes. The idea is just to change the 64 IOCTL structure so it lines up
> > with the old ones so that the same struct can be used from userspace.
> > Right now the first 32 of 64's result doesn't line up with the old
> > result field.
> >
> > - Charlie Scott Machalow
>
> OK, then this will work on all architectures I know:
>
> struct nvme_passthru_cmd64 {
>         __u8    opcode;
>         __u8    flags;
>         __u16   rsvd1;
>         __u32   nsid;
>         __u32   cdw2;
>         __u32   cdw3;
>         __u64   metadata;
>         __u64   addr;
>         __u32   metadata_len;
>         __u32   data_len;
>         __u32   cdw10;
>         __u32   cdw11;
>         __u32   cdw12;
>         __u32   cdw13;
>         __u32   cdw14;
>         __u32   cdw15;
>         __u32   timeout_ms;
>         __u32   rsvd2;
>         __u64   result;
> };
>
> Marta