[PATCH v4] nvme: add vectored-io support for user-passthru

[Kanchan Joshi]

On Mon, Feb 28, 2022 at 5:18 PM Christoph Hellwig <hch at lst.de> wrote:
>
> Btw, I noticed this is not wired up for the /dev/ngX character device.
> Can you send a follow on patch for that?

Err, do you see that it is not working? I actually tested it over both
block and char.
My test utility did write-vectored to /dev/nvme0n1 followed by
read-vectored from /dev/ng0n1, and did data-comparison. It passed.

Code wise, the handler for NVME_IOCTL_IO64_CMD_VEC is added insided
nvme_ns_ioctl().
- for non-multipath char node:
nvme_ns_chr_ioctl -> __nvme_ioctl -> nvme_ns_ioctl
- for multipath char node:
 nvme_ns_head_chr_ioctl -> nvme_ns_ioctl

Please let me know how I can produce the failure that you see.

Thanks,
-- 
Joshi