RE: [dpdk-dev] [PATCH v2 2/2] net/mlx5: fix resource leak when releasing a drop action

[Slava Ovsiienko <viacheslavo@nvidia.com>]

Hi, Yunjian

We have drop action in mlx5.
To create/destroy drop action we have 
mlx5_drop_action_create/ mlx5_drop_action_destroy common routines.

As PMD supports operation either over FW (Verbs in rdma_core) or SW/HW steering
with DevX objects the "virtual" methods are used for objects:

priv->obj_ops.drop_action_create(dev) - create drop action
   a) mlx5_ibv_drop_action_create()- use Verbs (dv-flow_en == 0)
   b) mlx5_devx_drop_action_create() - use DevX (dv-flow_en != 0)

priv->obj_ops.drop_action_destroy(dev) - destroy drop action
   a) mlx5_ibv_drop_action_destroy()- use Verbs (dv-flow_en == 0)
   b) mlx5_devx_drop_action_destroy() - use DevX (dv-flow_en != 0)


Let's consider DevX case.
mlx5_devx_drop_action_create()
    mlx5_rxq_devx_obj_drop_create()
    mlx5_devx_ind_table_new()
    mlx5_devx_hrxq_new()
         xxx_create_dest_tir()
         xxx_action_create_dest_tir()


mlx5_devx_drop_action_destroy()
    /* It seems action destroy is missing here */
    mlx5_devx_tir_destroy()
    mlx5_devx_ind_table_destroy()
    mlx5_rxq_devx_obj_drop_release()

So, yes, I agree. There is missing action destroy, it seems we have leakage.

Let's look at 
__mlx5_hrxq_remove()
   destroy_action()
   priv->obj_ops.hrxq_destroy();


And there we have a problem.
obj_ops.hrxq_destroy() - not always mlx5_devx_tir_destroy() is called.
It might be mlx5_ibv_qp_destroy() (for Verbas) and patch would not work.

So, instead of fixing __mlx5_hrxq_remove() and mlx5_devx_tir_destroy()
I would consider patching:
- mlx5_devx_drop_action_destroy()
- mlx5_ibv_drop_action_destroy
by adding action desatroying.

With best regards,
Slava


> -----Original Message-----
> From: wangyunjian <wangyunjian@huawei.com>
> Sent: Friday, September 23, 2022 12:32
> To: dev@dpdk.org
> Cc: Matan Azrad <matan@nvidia.com>; Raslan Darawsheh <rasland@nvidia.com>;
> Slava Ovsiienko <viacheslavo@nvidia.com>; Dmitry Kozlyuk
> <dkozlyuk@nvidia.com>; Huangshaozhang <huangshaozhang@huawei.com>;
> stable@dpdk.org
> Subject: RE: [dpdk-dev] [PATCH v2 2/2] net/mlx5: fix resource leak when
> releasing a drop action
> 
> Friendly ping.
> 
> > -----Original Message-----
> > From: wangyunjian
> > Sent: Tuesday, August 23, 2022 2:46 PM
> > To: dev@dpdk.org
> > Cc: matan@nvidia.com; rasland@nvidia.com; viacheslavo@nvidia.com;
> > dkozlyuk@nvidia.com; Huangshaozhang <huangshaozhang@huawei.com>;
> > wangyunjian <wangyunjian@huawei.com>; stable@dpdk.org
> > Subject: [dpdk-dev] [PATCH v2 2/2] net/mlx5: fix resource leak when
> > releasing a drop action
> >
> > Currently, the resources for hrxq->action are allocated in
> > mlx5_devx_hrxq_new(). But it was not being freed when the drop action
> > was released in mlx5_devx_drop_action_destroy().
> > So, fix is to free the resources in mlx5_devx_tir_destroy().
> >
> > Fixes: bc5bee028ebc ("net/mlx5: create drop queue using DevX")
> > Cc: stable@dpdk.org
> >
> > Signed-off-by: Yunjian Wang <wangyunjian@huawei.com>
> > ---
> >  drivers/net/mlx5/mlx5_devx.c | 7 +++++++  drivers/net/mlx5/mlx5_rxq.c
> > |
> > 6 ------
> >  2 files changed, 7 insertions(+), 6 deletions(-)
> >
> > diff --git a/drivers/net/mlx5/mlx5_devx.c
> > b/drivers/net/mlx5/mlx5_devx.c index
> > 6886ae1f22..09c8856f05 100644
> > --- a/drivers/net/mlx5/mlx5_devx.c
> > +++ b/drivers/net/mlx5/mlx5_devx.c
> > @@ -907,6 +907,13 @@ mlx5_devx_hrxq_new(struct rte_eth_dev *dev,
> > struct mlx5_hrxq *hrxq,  static void  mlx5_devx_tir_destroy(struct
> > mlx5_hrxq *hrxq)  {
> > +#if defined(HAVE_IBV_FLOW_DV_SUPPORT)
> > || !defined(HAVE_INFINIBAND_VERBS_H)
> > +	if (hrxq->hws_flags)
> > +		mlx5dr_action_destroy(hrxq->action);
> > +	else
> > +		mlx5_flow_os_destroy_flow_action(hrxq->action);
> > +	hrxq->action = NULL;
> > +#endif
> >  	claim_zero(mlx5_devx_cmd_destroy(hrxq->tir));
> >  }
> >
> > diff --git a/drivers/net/mlx5/mlx5_rxq.c b/drivers/net/mlx5/mlx5_rxq.c
> > index eaf23d0df4..e518fe9bfd 100644
> > --- a/drivers/net/mlx5/mlx5_rxq.c
> > +++ b/drivers/net/mlx5/mlx5_rxq.c
> > @@ -2861,12 +2861,6 @@ __mlx5_hrxq_remove(struct rte_eth_dev *dev,
> > struct mlx5_hrxq *hrxq)  {
> >  	struct mlx5_priv *priv = dev->data->dev_private;
> >
> > -#ifdef HAVE_IBV_FLOW_DV_SUPPORT
> > -	if (hrxq->hws_flags)
> > -		mlx5dr_action_destroy(hrxq->action);
> > -	else
> > -		mlx5_glue->destroy_flow_action(hrxq->action);
> > -#endif
> >  	priv->obj_ops.hrxq_destroy(hrxq);
> >  	if (!hrxq->standalone) {
> >  		mlx5_ind_table_obj_release(dev, hrxq->ind_table,
> > --
> > 2.27.0