Re: [PATCH] io_uring: return void from io_put_kbuf_comp()

[Jens Axboe <axboe@kernel.dk>]

On 3/29/24 9:50 AM, Ming Lei wrote:
> The two callers don't handle the return value of io_put_kbuf_comp(), so
> change its return type into void.

We might want to consider changing the name of it too, it's a bit
different in that it's just recyling/dropping this kbuf rather than
posting a completion on behalf of it.

Maybe io_kbuf_drop() would be better. Would distuingish it from the
normal use cases of "drop this kbuf and return the cflags representation
of it, as I'm posting a completionw ith it".

> Signed-off-by: Ming Lei <ming.lei@redhat.com>
> ---
>  io_uring/kbuf.h | 12 +++---------
>  1 file changed, 3 insertions(+), 9 deletions(-)
> 
> diff --git a/io_uring/kbuf.h b/io_uring/kbuf.h
> index 1c7b654ee726..86931fa655ad 100644
> --- a/io_uring/kbuf.h
> +++ b/io_uring/kbuf.h
> @@ -119,18 +119,12 @@ static inline void __io_put_kbuf_list(struct io_kiocb *req,
>  	}
>  }
>  
> -static inline unsigned int io_put_kbuf_comp(struct io_kiocb *req)
> +static inline void io_put_kbuf_comp(struct io_kiocb *req)
>  {
> -	unsigned int ret;
> -
>  	lockdep_assert_held(&req->ctx->completion_lock);
>  
> -	if (!(req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING)))
> -		return 0;
> -
> -	ret = IORING_CQE_F_BUFFER | (req->buf_index << IORING_CQE_BUFFER_SHIFT);
> -	__io_put_kbuf_list(req, &req->ctx->io_buffers_comp);
> -	return ret;
> +	if (req->flags & (REQ_F_BUFFER_SELECTED|REQ_F_BUFFER_RING))
> +		__io_put_kbuf_list(req, &req->ctx->io_buffers_comp);
>  }

If you post a v2 with the above suggestion, let's please just keep the
flags checking how it is. It's consistent with what we do elsewhere.

-- 
Jens Axboe