Re: [PATCH v3 08/13] io_uring: implement fixed buffers registration similar to fixed files

[Pavel Begunkov <asml.silence@gmail.com>]

On 08/01/2021 01:53, Bijan Mottahedeh wrote:
> 
>> Forgot to mention, I failed to find where you do
>> io_set_resource_node() in v4 for fixed reads/writes.
>> Also, it should be done during submission, io_prep_rw()
>> is the right place for that.
> 
> Would something like below be ok?  I renamed io_set_resource_node() to io_get_fixed_rsrc_ref() to make its function more clear and also distinguish it from io_sqe_rsrc_set_node().

looks good

> 
> diff --git a/fs/io_uring.c b/fs/io_uring.c
> index bd55d11..a9b9881 100644
> --- a/fs/io_uring.c
> +++ b/fs/io_uring.c
> @@ -1083,12 +1083,11 @@ static inline void io_clean_op(struct io_kiocb *req)
>                 __io_clean_op(req);
>  }
> 
> -static inline void io_set_resource_node(struct io_kiocb *req)
> +static inline void io_get_fixed_rsrc_ref(struct io_kiocb *req,
> +                                        struct fixed_rsrc_data *rsrc_data)
>  {
> -       struct io_ring_ctx *ctx = req->ctx;
> -
>         if (!req->fixed_rsrc_refs) {
> -               req->fixed_rsrc_refs = &ctx->file_data->node->refs;
> +               req->fixed_rsrc_refs = &rsrc_data->node->refs;
>                 percpu_ref_get(req->fixed_rsrc_refs);
>         }
>  }
> @@ -2928,6 +2927,9 @@ static int io_prep_rw(struct io_kiocb *req, const struct i
>         req->rw.addr = READ_ONCE(sqe->addr);
>         req->rw.len = READ_ONCE(sqe->len);
>         req->buf_index = READ_ONCE(sqe->buf_index);
> +       if (req->opcode == IORING_OP_READ_FIXED ||
> +           req->opcode == IORING_OP_WRITE_FIXED)
> +               io_get_fixed_rsrc_ref(req, ctx->buf_data);
>         return 0;
>  }
> 
> @@ -6452,7 +6454,7 @@ static struct file *io_file_get(struct io_submit_state *st
>                         return NULL;
>                 fd = array_index_nospec(fd, ctx->nr_user_files);
>                 file = io_file_from_index(ctx, fd);
> -               io_set_resource_node(req);
> +               io_get_fixed_rsrc_ref(req, ctx->file_data);
>         } else {
>                 trace_io_uring_file_get(ctx, fd);
>                 file = __io_file_get(state, fd);
> 

-- 
Pavel Begunkov