[PATCH] [net-next] net/mlx5e: xsk: dynamically allocate mlx5e_channel_param

[PATCH] [net-next] net/mlx5e: xsk: dynamically allocate mlx5e_channel_param

[Arnd Bergmann]

The structure is too large to put on the stack, resulting in a
warning on 32-bit ARM:

drivers/net/ethernet/mellanox/mlx5/core/en/xsk/setup.c:59:5: error: stack frame size of 1344 bytes in function
      'mlx5e_open_xsk' [-Werror,-Wframe-larger-than=]

Use kzalloc() instead.

Fixes: a038e9794541 ("net/mlx5e: Add XSK zero-copy support")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 .../mellanox/mlx5/core/en/xsk/setup.c         | 25 ++++++++++++-------
 1 file changed, 16 insertions(+), 9 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/setup.c b/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/setup.c
index aaffa6f68dc0..db9bbec68dbf 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/setup.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/setup.c
@@ -60,24 +60,28 @@ int mlx5e_open_xsk(struct mlx5e_priv *priv, struct mlx5e_params *params,
 		   struct mlx5e_xsk_param *xsk, struct xdp_umem *umem,
 		   struct mlx5e_channel *c)
 {
-	struct mlx5e_channel_param cparam = {};
+	struct mlx5e_channel_param *cparam;
 	struct dim_cq_moder icocq_moder = {};
 	int err;
 
 	if (!mlx5e_validate_xsk_param(params, xsk, priv->mdev))
 		return -EINVAL;
 
-	mlx5e_build_xsk_cparam(priv, params, xsk, &cparam);
+	cparam = kzalloc(sizeof(*cparam), GFP_KERNEL);
+	if (!cparam)
+		return -ENOMEM;
 
-	err = mlx5e_open_cq(c, params->rx_cq_moderation, &cparam.rx_cq, &c->xskrq.cq);
+	mlx5e_build_xsk_cparam(priv, params, xsk, cparam);
+
+	err = mlx5e_open_cq(c, params->rx_cq_moderation, &cparam->rx_cq, &c->xskrq.cq);
 	if (unlikely(err))
-		return err;
+		goto err_kfree_cparam;
 
-	err = mlx5e_open_rq(c, params, &cparam.rq, xsk, umem, &c->xskrq);
+	err = mlx5e_open_rq(c, params, &cparam->rq, xsk, umem, &c->xskrq);
 	if (unlikely(err))
 		goto err_close_rx_cq;
 
-	err = mlx5e_open_cq(c, params->tx_cq_moderation, &cparam.tx_cq, &c->xsksq.cq);
+	err = mlx5e_open_cq(c, params->tx_cq_moderation, &cparam->tx_cq, &c->xsksq.cq);
 	if (unlikely(err))
 		goto err_close_rq;
 
@@ -87,18 +91,18 @@ int mlx5e_open_xsk(struct mlx5e_priv *priv, struct mlx5e_params *params,
 	 * is disabled and then reenabled, but the SQ continues receiving CQEs
 	 * from the old UMEM.
 	 */
-	err = mlx5e_open_xdpsq(c, params, &cparam.xdp_sq, umem, &c->xsksq, true);
+	err = mlx5e_open_xdpsq(c, params, &cparam->xdp_sq, umem, &c->xsksq, true);
 	if (unlikely(err))
 		goto err_close_tx_cq;
 
-	err = mlx5e_open_cq(c, icocq_moder, &cparam.icosq_cq, &c->xskicosq.cq);
+	err = mlx5e_open_cq(c, icocq_moder, &cparam->icosq_cq, &c->xskicosq.cq);
 	if (unlikely(err))
 		goto err_close_sq;
 
 	/* Create a dedicated SQ for posting NOPs whenever we need an IRQ to be
 	 * triggered and NAPI to be called on the correct CPU.
 	 */
-	err = mlx5e_open_icosq(c, params, &cparam.icosq, &c->xskicosq);
+	err = mlx5e_open_icosq(c, params, &cparam->icosq, &c->xskicosq);
 	if (unlikely(err))
 		goto err_close_icocq;
 
@@ -123,6 +127,9 @@ int mlx5e_open_xsk(struct mlx5e_priv *priv, struct mlx5e_params *params,
 err_close_rx_cq:
 	mlx5e_close_cq(&c->xskrq.cq);
 
+err_kfree_cparam:
+	kfree(cparam);
+
 	return err;
 }
 
-- 
2.20.0

Re: [PATCH] [net-next] net/mlx5e: xsk: dynamically allocate mlx5e_channel_param

[Maxim Mikityanskiy]

On 2019-07-08 15:55, Arnd Bergmann wrote:
> The structure is too large to put on the stack, resulting in a
> warning on 32-bit ARM:
> 
> drivers/net/ethernet/mellanox/mlx5/core/en/xsk/setup.c:59:5: error: stack frame size of 1344 bytes in function
>        'mlx5e_open_xsk' [-Werror,-Wframe-larger-than=]
> 
> Use kzalloc() instead.
> 
> Fixes: a038e9794541 ("net/mlx5e: Add XSK zero-copy support")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
>   .../mellanox/mlx5/core/en/xsk/setup.c         | 25 ++++++++++++-------
>   1 file changed, 16 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/setup.c b/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/setup.c
> index aaffa6f68dc0..db9bbec68dbf 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/setup.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/setup.c
> @@ -60,24 +60,28 @@ int mlx5e_open_xsk(struct mlx5e_priv *priv, struct mlx5e_params *params,
>   		   struct mlx5e_xsk_param *xsk, struct xdp_umem *umem,
>   		   struct mlx5e_channel *c)
>   {
> -	struct mlx5e_channel_param cparam = {};
> +	struct mlx5e_channel_param *cparam;
>   	struct dim_cq_moder icocq_moder = {};
>   	int err;
>   
>   	if (!mlx5e_validate_xsk_param(params, xsk, priv->mdev))
>   		return -EINVAL;
>   
> -	mlx5e_build_xsk_cparam(priv, params, xsk, &cparam);
> +	cparam = kzalloc(sizeof(*cparam), GFP_KERNEL);

Similar code in mlx5e_open_channels (en_main.c) uses kvzalloc. Although 
the struct is currently smaller than a page anyway, and there should be 
no difference in behavior now, I suggest using the same alloc function 
to keep code uniform.

> +	if (!cparam)
> +		return -ENOMEM;
>   
> -	err = mlx5e_open_cq(c, params->rx_cq_moderation, &cparam.rx_cq, &c->xskrq.cq);
> +	mlx5e_build_xsk_cparam(priv, params, xsk, cparam);
> +
> +	err = mlx5e_open_cq(c, params->rx_cq_moderation, &cparam->rx_cq, &c->xskrq.cq);
>   	if (unlikely(err))
> -		return err;
> +		goto err_kfree_cparam;
>   
> -	err = mlx5e_open_rq(c, params, &cparam.rq, xsk, umem, &c->xskrq);
> +	err = mlx5e_open_rq(c, params, &cparam->rq, xsk, umem, &c->xskrq);
>   	if (unlikely(err))
>   		goto err_close_rx_cq;
>   
> -	err = mlx5e_open_cq(c, params->tx_cq_moderation, &cparam.tx_cq, &c->xsksq.cq);
> +	err = mlx5e_open_cq(c, params->tx_cq_moderation, &cparam->tx_cq, &c->xsksq.cq);
>   	if (unlikely(err))
>   		goto err_close_rq;
>   
> @@ -87,18 +91,18 @@ int mlx5e_open_xsk(struct mlx5e_priv *priv, struct mlx5e_params *params,
>   	 * is disabled and then reenabled, but the SQ continues receiving CQEs
>   	 * from the old UMEM.
>   	 */
> -	err = mlx5e_open_xdpsq(c, params, &cparam.xdp_sq, umem, &c->xsksq, true);
> +	err = mlx5e_open_xdpsq(c, params, &cparam->xdp_sq, umem, &c->xsksq, true);
>   	if (unlikely(err))
>   		goto err_close_tx_cq;
>   
> -	err = mlx5e_open_cq(c, icocq_moder, &cparam.icosq_cq, &c->xskicosq.cq);
> +	err = mlx5e_open_cq(c, icocq_moder, &cparam->icosq_cq, &c->xskicosq.cq);
>   	if (unlikely(err))
>   		goto err_close_sq;
>   
>   	/* Create a dedicated SQ for posting NOPs whenever we need an IRQ to be
>   	 * triggered and NAPI to be called on the correct CPU.
>   	 */
> -	err = mlx5e_open_icosq(c, params, &cparam.icosq, &c->xskicosq);
> +	err = mlx5e_open_icosq(c, params, &cparam->icosq, &c->xskicosq);
>   	if (unlikely(err))
>   		goto err_close_icocq;
>   

Here is kfree missing. It's a memory leak in the good path.

Thanks!

> @@ -123,6 +127,9 @@ int mlx5e_open_xsk(struct mlx5e_priv *priv, struct mlx5e_params *params,
>   err_close_rx_cq:
>   	mlx5e_close_cq(&c->xskrq.cq);
>   
> +err_kfree_cparam:
> +	kfree(cparam);
> +
>   	return err;
>   }
>   
> 

Re: [PATCH] [net-next] net/mlx5e: xsk: dynamically allocate mlx5e_channel_param

[Maxim Mikityanskiy]

On 2019-07-08 18:16, Maxim Mikityanskiy wrote:
> On 2019-07-08 15:55, Arnd Bergmann wrote:
>> -	mlx5e_build_xsk_cparam(priv, params, xsk, &cparam);
>> +	cparam = kzalloc(sizeof(*cparam), GFP_KERNEL);
> 
> Similar code in mlx5e_open_channels (en_main.c) uses kvzalloc. Although
> the struct is currently smaller than a page anyway, and there should be
> no difference in behavior now, I suggest using the same alloc function
> to keep code uniform.
> 
>>    	/* Create a dedicated SQ for posting NOPs whenever we need an IRQ to be
>>    	 * triggered and NAPI to be called on the correct CPU.
>>    	 */
>> -	err = mlx5e_open_icosq(c, params, &cparam.icosq, &c->xskicosq);
>> +	err = mlx5e_open_icosq(c, params, &cparam->icosq, &c->xskicosq);
>>    	if (unlikely(err))
>>    		goto err_close_icocq;
>>    
> 
> Here is kfree missing. It's a memory leak in the good path.

Arnd, I'm going to take over your patch and respin it, addressing my own 
comments, because it's been quite a while, and we want to have this fix.

Thanks for spotting it.

Re: [PATCH] [net-next] net/mlx5e: xsk: dynamically allocate mlx5e_channel_param

[Arnd Bergmann]

On Tue, Jul 23, 2019 at 1:21 PM Maxim Mikityanskiy <maximmi@mellanox.com> wrote:
> On 2019-07-08 18:16, Maxim Mikityanskiy wrote:
> > On 2019-07-08 15:55, Arnd Bergmann wrote:
> >> -    mlx5e_build_xsk_cparam(priv, params, xsk, &cparam);
> >> +    cparam = kzalloc(sizeof(*cparam), GFP_KERNEL);
> >
> > Similar code in mlx5e_open_channels (en_main.c) uses kvzalloc. Although
> > the struct is currently smaller than a page anyway, and there should be
> > no difference in behavior now, I suggest using the same alloc function
> > to keep code uniform.
> >
> >>      /* Create a dedicated SQ for posting NOPs whenever we need an IRQ to be
> >>       * triggered and NAPI to be called on the correct CPU.
> >>       */
> >> -    err = mlx5e_open_icosq(c, params, &cparam.icosq, &c->xskicosq);
> >> +    err = mlx5e_open_icosq(c, params, &cparam->icosq, &c->xskicosq);
> >>      if (unlikely(err))
> >>              goto err_close_icocq;
> >>
> >
> > Here is kfree missing. It's a memory leak in the good path.
>
> Arnd, I'm going to take over your patch and respin it, addressing my own
> comments, because it's been quite a while, and we want to have this fix.
>
> Thanks for spotting it.

Thanks for taking care of it now. I was planning to do a respin, but
the reply got lost in the depth of my inbox so I forgot about it.

      Arnd