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

[Juanlu Herrero <juanlu@fastmail.com>]

On Mon, Jul 27, 2026 at 06:36:13PM -0600, Jakub Kicinski wrote:
> 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.


Thanks for the review and makes sense. I will fix these things in v4.