Re: [PATCH 0/3] implement direct IO with integrity

[Jens Axboe <axboe@kernel.dk>]

On 10/28/21 5:24 AM, Alexander V. Buev wrote:
> This series of patches makes possible to do direct block IO
> with integrity payload using io uring kernel interface.
> Userspace app can utilize READV/WRITEV operation with a new 
> (unused before) flag in sqe struct to mark IO request as 
> "request with integrity payload". 
> When this flag is set, the last of provided iovecs
> must contain pointer and length of this integrity payload.
> 
> Alexander V. Buev (3):
>   block: bio-integrity: add PI iovec to bio
>   block: io_uring: add IO_WITH_PI flag to SQE
>   block: fops: handle IOCB_USE_PI in direct IO
> 
>  block/bio-integrity.c         | 124 +++++++++++++++++++++++++++++++++-
>  block/fops.c                  |  71 +++++++++++++++++++
>  fs/io_uring.c                 |  32 ++++++++-
>  include/linux/bio.h           |   8 +++
>  include/linux/fs.h            |   1 +
>  include/uapi/linux/io_uring.h |   3 +
>  6 files changed, 235 insertions(+), 4 deletions(-)

A couple of suggestions on this:

1) Don't think we need an IOSQE flag, those are mostly reserved for
   modifiers that apply to (mostly) all kinds of requests
2) I think this would be cleaner as a separate command, rather than
   need odd adjustments and iov assumptions. That also gets it out
   of the fast path.

I'd add IORING_OP_READV_PI and IORING_OP_WRITEV_PI for this, I think
you'd end up with a much cleaner implementation that way.

-- 
Jens Axboe