Re: [PATCH net-next v3 5/6] selftests: net: add multithread server support to iou-zcrx

[Jakub Kicinski <kuba@kernel.org>]

On Wed, 22 Jul 2026 15:39:49 -0500 Juanlu Herrero wrote:
> Run the iou-zcrx server as N worker threads, each owning one receive
> queue with its own io_uring and zero-copy receive (zcrx) ifq, so the
> test can exercise multi-queue zero-copy receive.
> 
> The main thread owns the listening socket, accepts connections, and
> dispatches each to the worker owning the queue it landed on by matching
> SO_INCOMING_NAPI_ID against per-queue NAPI IDs.
> 
> Assisted-by: Claude:claude-opus-4-8
> Signed-off-by: Juanlu Herrero <juanlu@fastmail.com>
> ---
>  .../testing/selftests/drivers/net/hw/Makefile |   8 +-
>  .../selftests/drivers/net/hw/iou-zcrx.c       | 297 ++++++++++++++----
>  2 files changed, 237 insertions(+), 68 deletions(-)
> 
> diff --git a/tools/testing/selftests/drivers/net/hw/Makefile b/tools/testing/selftests/drivers/net/hw/Makefile
> index 3cab3b4adbb2e..946938371c763 100644
> --- a/tools/testing/selftests/drivers/net/hw/Makefile
> +++ b/tools/testing/selftests/drivers/net/hw/Makefile
> @@ -7,14 +7,11 @@ HAS_IOURING_ZCRX := $(shell \
>  	     'int main() {return 0;}' | \
>  	$(CC) -luring -x c - -o /dev/null 2>&1 && echo y)
>  
> -ifeq ($(HAS_IOURING_ZCRX),y)
> -COND_GEN_FILES += iou-zcrx
> -else
> +ifneq ($(HAS_IOURING_ZCRX),y)
>  $(warning excluding iouring tests, liburing not installed or too old)
>  endif

why not move this down together with the if condition?

>  TEST_GEN_FILES := \
> -	$(COND_GEN_FILES) \
>  # end of TEST_GEN_FILES

This is now empty, why keep it?

>  TEST_PROGS = \
> @@ -72,6 +69,9 @@ YNL_GEN_FILES := \
>  	ncdevmem \
>  	toeplitz \
>  # end of YNL_GEN_FILES
> +ifeq ($(HAS_IOURING_ZCRX),y)
> +YNL_GEN_FILES += iou-zcrx

Follow the 

BLA := \
	something \
# end of BLA

formatting for the variables, please

> +endif
>  TEST_GEN_FILES += $(YNL_GEN_FILES)
>  TEST_GEN_FILES += $(patsubst %.c,%.o,$(wildcard *.bpf.c))
>  

> +	{
> +		int conns_per_thread = cfg_num_threads > 1 ?
> +				       CONNS_PER_THREAD : 1;
> +		int total_conns = conns_per_thread * cfg_num_threads;
> +		int accepted = 0;
> +		int connfd;

Floating code blocks like this are considered poor coding style in the
kernel.