Re: [PATCH v1 2/2] fuse: support io-uring registered buffers

[Joanne Koong <joannelkoong@gmail.com>]

> diff --git a/fs/fuse/dev_uring_i.h b/fs/fuse/dev_uring_i.h
> index 51a563922ce1..748c87e325f5 100644
> --- a/fs/fuse/dev_uring_i.h
> +++ b/fs/fuse/dev_uring_i.h
> @@ -38,9 +38,20 @@ enum fuse_ring_req_state {
>
>  /** A fuse ring entry, part of the ring queue */
>  struct fuse_ring_ent {
> -       /* userspace buffer */
> -       struct fuse_uring_req_header __user *headers;
> -       void __user *payload;
> +       /* True if daemon has registered its buffers ahead of time */
> +       bool is_fixed_buffer;
> +       union {
> +               /* userspace buffer */
> +               struct {
> +                       struct fuse_uring_req_header __user *headers;
> +                       void __user *payload;
> +               } user;
> +
> +               struct {
> +                       struct iov_iter payload_iter;
> +                       struct iov_iter headers_iter;
> +               } fixed_buffer;
> +       };

The iters need to be reconstructed instead of recycling the same one
since the buffer could be unregistered by userspace even while the
server is running, even if libfuse doesn't do that. I'll account for
this in v2.

Thanks,
Joanne

>
>         /* the ring queue that owns the request */
>         struct fuse_ring_queue *queue;
> --
> 2.47.3
>