Re: [PATCH 4/5] io_uring/zcrx: move zcrx region to struct io_zcrx_ifq

[David Wei <dw@davidwei.uk>]

On 2025-04-16 08:21, Pavel Begunkov wrote:
> Refill queue region is a part of zcrx and should stay in struct
> io_zcrx_ifq. We can't have multiple queues without it.
> 
> Note: ctx->ifq assignments are now protected by mmap_lock as it's in
> the mmap region look up path.
> 
> Signed-off-by: Pavel Begunkov <asml.silence@gmail.com>
> ---
>  include/linux/io_uring_types.h |  2 --
>  io_uring/zcrx.c                | 20 ++++++++++++--------
>  io_uring/zcrx.h                |  1 +
>  3 files changed, 13 insertions(+), 10 deletions(-)
> 
> diff --git a/include/linux/io_uring_types.h b/include/linux/io_uring_types.h
> index 3b467879bca8..06d722289fc5 100644
> --- a/include/linux/io_uring_types.h
> +++ b/include/linux/io_uring_types.h
> @@ -448,8 +448,6 @@ struct io_ring_ctx {
>  	struct io_mapped_region		ring_region;
>  	/* used for optimised request parameter and wait argument passing  */
>  	struct io_mapped_region		param_region;
> -	/* just one zcrx per ring for now, will move to io_zcrx_ifq eventually */
> -	struct io_mapped_region		zcrx_region;
>  };
>  
>  /*
> diff --git a/io_uring/zcrx.c b/io_uring/zcrx.c
> index 652daff0eb8d..d56665fd103d 100644
> --- a/io_uring/zcrx.c
> +++ b/io_uring/zcrx.c
> @@ -160,12 +160,11 @@ static int io_allocate_rbuf_ring(struct io_zcrx_ifq *ifq,
>  	if (size > rd->size)
>  		return -EINVAL;
>  
> -	ret = io_create_region_mmap_safe(ifq->ctx, &ifq->ctx->zcrx_region, rd,
> -					 IORING_MAP_OFF_ZCRX_REGION);
> +	ret = io_create_region(ifq->ctx, &ifq->region, rd, IORING_MAP_OFF_ZCRX_REGION);

Why is this changed to io_create_region()? I don't see the caller of
io_allocate_rbuf_ring() changing or taking mmap_lock.