[PATCH] net/mlx5: fix external Rx and Tx queues access

[Thomas Monjalon]

18/08/2025 08:32, Raslan Darawsheh:
> On 31/07/2025 9:08 AM, Gregory Etelson wrote:
> > mlx5_ext_rxq_get() and mlx5_ext_txq_get() functions did not return
> > NULL value if query index was not referencing external queue.
> > 
> > As a result, calling functions did not expect the NULL on return.

It is not clear what is the problem.


> > External Rx queue:
> > 
> > - In mlx5_ext_rxq_get() remove assert and return NULL if a queue index
> >    does not point to a valid external queue.
> > 
> > - In mlx5_ext_rxq_verify() validate that probed queue index references
> >    a valid extern queue.
> > 
> > External Tx queue:
> > 
> > -  In mlx5_ext_txq_get() remove assert and return NULL if a queue index
> >     does not point to a valid external queue.
> > 
> > - In mlx5_ext_txq_verify() validate that probed queue index references
> >    a valid extern queue.
> > 
> > Fixes: 311b17e669ab ("net/mlx5: support queue/RSS actions for external Rx queue")
> > 
> > Signed-off-by: Gregory Etelson <getelson at nvidia.com>
> > Acked-by: Dariusz Sosnowski <dsosnowski at nvidia.com>
> 
> Patch applied to next-net-mlx,

The patch is returning NULL but it is not handled in calling functions.
Thus MinGW compiler detects a problem:

In function 'mlx5_ext_rxq_ref',
    inlined from 'mlx5_rxqs_ref' at ../../dpdk/drivers/net/mlx5/mlx5_rxq.c:2303:8:
../../dpdk/lib/eal/include/rte_stdatomic.h:155:9: error: '__atomic_fetch_add_4' writing 4 bytes into a region of size 0 overflows the destination [-Werror=stringop-overflow=]
  155 |         __atomic_fetch_add(ptr, val, memorder)
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
../../dpdk/drivers/net/mlx5/mlx5_rxq.c:2215:9: note: in expansion of macro 'rte_atomic_fetch_add_explicit'
 2215 |         rte_atomic_fetch_add_explicit(&rxq->refcnt, 1, rte_memory_order_relaxed);
      |         ^~~~~~~~~~~~~~~~~~~~~~~~~~~~~
In function 'mlx5_rxqs_ref':
cc1: note: destination object is likely at address zero

I dropped this patch while pulling next-net-mlx into main.

Please provide a new version of the patch addressing these issues.
Thanks