Re: [PATCH] block/blkio: Make driver nvme-io_uring take a "path" instead of a "filename"

[Stefano Garzarella]

On Sat, Oct 29, 2022 at 12:38:54AM +0100, Alberto Faria wrote:
> The nvme-io_uring driver expects a character special file such as
> /dev/ng0n1. Follow the convention of having a "filename" option when a
> regular file is expected, and a "path" option otherwise.
>
> This makes io_uring the only libblkio-based driver with a "filename"
> option, as it accepts a regular file (even though it can also take a
> block special file).
>
> Signed-off-by: Alberto Faria <afaria@redhat.com>
> ---
> block/blkio.c        | 12 ++++++++----
> qapi/block-core.json |  4 ++--
> 2 files changed, 10 insertions(+), 6 deletions(-)
>
> diff --git a/block/blkio.c b/block/blkio.c
> index 82f26eedd2..5f600e5e9e 100644
> --- a/block/blkio.c
> +++ b/block/blkio.c
> @@ -639,12 +639,17 @@ static int blkio_io_uring_open(BlockDriverState *bs, 
> QDict *options, int flags,
> static int blkio_nvme_io_uring(BlockDriverState *bs, QDict *options, int flags,
>                                Error **errp)
> {
> -    const char *filename = qdict_get_str(options, "filename");
> +    const char *path = qdict_get_try_str(options, "path");
>     BDRVBlkioState *s = bs->opaque;
>     int ret;
>
> -    ret = blkio_set_str(s->blkio, "path", filename);
> -    qdict_del(options, "filename");
> +    if (!path) {
> +        error_setg(errp, "missing 'path' option");
> +        return -EINVAL;
> +    }
> +
> +    ret = blkio_set_str(s->blkio, "path", path);
> +    qdict_del(options, "path");
>     if (ret < 0) {
>         error_setg_errno(errp, -ret, "failed to set path: %s",
>                          blkio_get_error_msg());
> @@ -986,7 +991,6 @@ static BlockDriver bdrv_io_uring = BLKIO_DRIVER(
>
> static BlockDriver bdrv_nvme_io_uring = BLKIO_DRIVER(
>     DRIVER_NVME_IO_URING,
> -    .bdrv_needs_filename = true,
> );
>
> static BlockDriver bdrv_virtio_blk_vhost_user = BLKIO_DRIVER(
> diff --git a/qapi/block-core.json b/qapi/block-core.json
> index cb5079e645..6d36c0ed8b 100644
> --- a/qapi/block-core.json
> +++ b/qapi/block-core.json
> @@ -3703,12 +3703,12 @@
> #
> # Driver specific block device options for the nvme-io_uring backend.
> #
> -# @filename: path to the image file
> +# @path: path to the image file

Maybe we can update the "path" description with something similar to 
what we have in the libblkio docs:
  path to the NVMe namespace's character device (e.g., `/dev/ng0n1`).

Thanks,
Stefano