2021-03-08 15:35:35

by Arnd Bergmann

[permalink] [raw]
Subject: [PATCH] net/mlx5e: allocate 'indirection_rqt' buffer dynamically

From: Arnd Bergmann <[email protected]>

Increasing the size of the indirection_rqt array from 128 to 256 bytes
pushed the stack usage of the mlx5e_hairpin_fill_rqt_rqns() function
over the warning limit when building with clang and CONFIG_KASAN:

drivers/net/ethernet/mellanox/mlx5/core/en_tc.c:970:1: error: stack frame size of 1180 bytes in function 'mlx5e_tc_add_nic_flow' [-Werror,-Wframe-larger-than=]

Using dynamic allocation here is safe because the caller does the
same, and it reduces the stack usage of the function to just a few
bytes.

Fixes: 1dd55ba2fb70 ("net/mlx5e: Increase indirection RQ table size to 256")
Signed-off-by: Arnd Bergmann <[email protected]>
---
drivers/net/ethernet/mellanox/mlx5/core/en_tc.c | 16 +++++++++++++---
1 file changed, 13 insertions(+), 3 deletions(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
index 0da69b98f38f..66f98618dc13 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
@@ -445,12 +445,16 @@ static void mlx5e_hairpin_destroy_transport(struct mlx5e_hairpin *hp)
mlx5_core_dealloc_transport_domain(hp->func_mdev, hp->tdn);
}

-static void mlx5e_hairpin_fill_rqt_rqns(struct mlx5e_hairpin *hp, void *rqtc)
+static int mlx5e_hairpin_fill_rqt_rqns(struct mlx5e_hairpin *hp, void *rqtc)
{
- u32 indirection_rqt[MLX5E_INDIR_RQT_SIZE], rqn;
+ u32 *indirection_rqt, rqn;
struct mlx5e_priv *priv = hp->func_priv;
int i, ix, sz = MLX5E_INDIR_RQT_SIZE;

+ indirection_rqt = kzalloc(sz, GFP_KERNEL);
+ if (!indirection_rqt)
+ return -ENOMEM;
+
mlx5e_build_default_indir_rqt(indirection_rqt, sz,
hp->num_channels);

@@ -462,6 +466,9 @@ static void mlx5e_hairpin_fill_rqt_rqns(struct mlx5e_hairpin *hp, void *rqtc)
rqn = hp->pair->rqn[ix];
MLX5_SET(rqtc, rqtc, rq_num[i], rqn);
}
+
+ kfree(indirection_rqt);
+ return 0;
}

static int mlx5e_hairpin_create_indirect_rqt(struct mlx5e_hairpin *hp)
@@ -482,12 +489,15 @@ static int mlx5e_hairpin_create_indirect_rqt(struct mlx5e_hairpin *hp)
MLX5_SET(rqtc, rqtc, rqt_actual_size, sz);
MLX5_SET(rqtc, rqtc, rqt_max_size, sz);

- mlx5e_hairpin_fill_rqt_rqns(hp, rqtc);
+ err = mlx5e_hairpin_fill_rqt_rqns(hp, rqtc);
+ if (err)
+ goto out;

err = mlx5_core_create_rqt(mdev, in, inlen, &hp->indir_rqt.rqtn);
if (!err)
hp->indir_rqt.enabled = true;

+out:
kvfree(in);
return err;
}
--
2.29.2


2021-03-08 16:30:43

by Tariq Toukan

[permalink] [raw]
Subject: Re: [PATCH] net/mlx5e: allocate 'indirection_rqt' buffer dynamically



On 3/8/2021 5:32 PM, Arnd Bergmann wrote:
> From: Arnd Bergmann <[email protected]>
>
> Increasing the size of the indirection_rqt array from 128 to 256 bytes
> pushed the stack usage of the mlx5e_hairpin_fill_rqt_rqns() function
> over the warning limit when building with clang and CONFIG_KASAN:
>
> drivers/net/ethernet/mellanox/mlx5/core/en_tc.c:970:1: error: stack frame size of 1180 bytes in function 'mlx5e_tc_add_nic_flow' [-Werror,-Wframe-larger-than=]
>
> Using dynamic allocation here is safe because the caller does the
> same, and it reduces the stack usage of the function to just a few
> bytes.
>
> Fixes: 1dd55ba2fb70 ("net/mlx5e: Increase indirection RQ table size to 256")
> Signed-off-by: Arnd Bergmann <[email protected]>
> ---
> drivers/net/ethernet/mellanox/mlx5/core/en_tc.c | 16 +++++++++++++---
> 1 file changed, 13 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
> index 0da69b98f38f..66f98618dc13 100644
> --- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
> +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
> @@ -445,12 +445,16 @@ static void mlx5e_hairpin_destroy_transport(struct mlx5e_hairpin *hp)
> mlx5_core_dealloc_transport_domain(hp->func_mdev, hp->tdn);
> }
>
> -static void mlx5e_hairpin_fill_rqt_rqns(struct mlx5e_hairpin *hp, void *rqtc)
> +static int mlx5e_hairpin_fill_rqt_rqns(struct mlx5e_hairpin *hp, void *rqtc)
> {
> - u32 indirection_rqt[MLX5E_INDIR_RQT_SIZE], rqn;
> + u32 *indirection_rqt, rqn;
> struct mlx5e_priv *priv = hp->func_priv;
> int i, ix, sz = MLX5E_INDIR_RQT_SIZE;
>
> + indirection_rqt = kzalloc(sz, GFP_KERNEL);
> + if (!indirection_rqt)
> + return -ENOMEM;
> +
> mlx5e_build_default_indir_rqt(indirection_rqt, sz,
> hp->num_channels);
>
> @@ -462,6 +466,9 @@ static void mlx5e_hairpin_fill_rqt_rqns(struct mlx5e_hairpin *hp, void *rqtc)
> rqn = hp->pair->rqn[ix];
> MLX5_SET(rqtc, rqtc, rq_num[i], rqn);
> }
> +
> + kfree(indirection_rqt);
> + return 0;
> }
>
> static int mlx5e_hairpin_create_indirect_rqt(struct mlx5e_hairpin *hp)
> @@ -482,12 +489,15 @@ static int mlx5e_hairpin_create_indirect_rqt(struct mlx5e_hairpin *hp)
> MLX5_SET(rqtc, rqtc, rqt_actual_size, sz);
> MLX5_SET(rqtc, rqtc, rqt_max_size, sz);
>
> - mlx5e_hairpin_fill_rqt_rqns(hp, rqtc);
> + err = mlx5e_hairpin_fill_rqt_rqns(hp, rqtc);
> + if (err)
> + goto out;
>
> err = mlx5_core_create_rqt(mdev, in, inlen, &hp->indir_rqt.rqtn);
> if (!err)
> hp->indir_rqt.enabled = true;
>
> +out:
> kvfree(in);
> return err;
> }
>

Reviewed-by: Tariq Toukan <[email protected]>
Thanks for your patch.

Tariq

2021-03-11 22:52:59

by Saeed Mahameed

[permalink] [raw]
Subject: Re: [PATCH] net/mlx5e: allocate 'indirection_rqt' buffer dynamically

On Mon, 2021-03-08 at 18:28 +0200, Tariq Toukan wrote:
>
>
> On 3/8/2021 5:32 PM, Arnd Bergmann wrote:
> > From: Arnd Bergmann <[email protected]>
> >
> > Increasing the size of the indirection_rqt array from 128 to 256
> > bytes
> > pushed the stack usage of the mlx5e_hairpin_fill_rqt_rqns()
> > function
> > over the warning limit when building with clang and CONFIG_KASAN:
> >
> > drivers/net/ethernet/mellanox/mlx5/core/en_tc.c:970:1: error: stack
> > frame size of 1180 bytes in function 'mlx5e_tc_add_nic_flow' [-
> > Werror,-Wframe-larger-than=]
> >
> > Using dynamic allocation here is safe because the caller does the
> > same, and it reduces the stack usage of the function to just a few
> > bytes.
> >
> > Fixes: 1dd55ba2fb70 ("net/mlx5e: Increase indirection RQ table size
> > to 256")
> > Signed-off-by: Arnd Bergmann <[email protected]>
> > ---
> >   drivers/net/ethernet/mellanox/mlx5/core/en_tc.c | 16
> > +++++++++++++---
> >   1 file changed, 13 insertions(+), 3 deletions(-)
> >
> > diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
> > b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
> > index 0da69b98f38f..66f98618dc13 100644
> > --- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
> > +++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
> > @@ -445,12 +445,16 @@ static void
> > mlx5e_hairpin_destroy_transport(struct mlx5e_hairpin *hp)
> >         mlx5_core_dealloc_transport_domain(hp->func_mdev, hp->tdn);
> >   }
> >  
> > -static void mlx5e_hairpin_fill_rqt_rqns(struct mlx5e_hairpin *hp,
> > void *rqtc)
> > +static int mlx5e_hairpin_fill_rqt_rqns(struct mlx5e_hairpin *hp,
> > void *rqtc)
> >   {
> > -       u32 indirection_rqt[MLX5E_INDIR_RQT_SIZE], rqn;
> > +       u32 *indirection_rqt, rqn;
> >         struct mlx5e_priv *priv = hp->func_priv;
> >         int i, ix, sz = MLX5E_INDIR_RQT_SIZE;
> >  
> > +       indirection_rqt = kzalloc(sz, GFP_KERNEL);
> > +       if (!indirection_rqt)
> > +               return -ENOMEM;
> > +
> >         mlx5e_build_default_indir_rqt(indirection_rqt, sz,
> >                                       hp->num_channels);
> >  
> > @@ -462,6 +466,9 @@ static void mlx5e_hairpin_fill_rqt_rqns(struct
> > mlx5e_hairpin *hp, void *rqtc)
> >                 rqn = hp->pair->rqn[ix];
> >                 MLX5_SET(rqtc, rqtc, rq_num[i], rqn);
> >         }
> > +
> > +       kfree(indirection_rqt);
> > +       return 0;
> >   }
> >  
> >   static int mlx5e_hairpin_create_indirect_rqt(struct mlx5e_hairpin
> > *hp)
> > @@ -482,12 +489,15 @@ static int
> > mlx5e_hairpin_create_indirect_rqt(struct mlx5e_hairpin *hp)
> >         MLX5_SET(rqtc, rqtc, rqt_actual_size, sz);
> >         MLX5_SET(rqtc, rqtc, rqt_max_size, sz);
> >  
> > -       mlx5e_hairpin_fill_rqt_rqns(hp, rqtc);
> > +       err = mlx5e_hairpin_fill_rqt_rqns(hp, rqtc);
> > +       if (err)
> > +               goto out;
> >  
> >         err = mlx5_core_create_rqt(mdev, in, inlen, &hp-
> > >indir_rqt.rqtn);
> >         if (!err)
> >                 hp->indir_rqt.enabled = true;
> >  
> > +out:
> >         kvfree(in);
> >         return err;
> >   }
> >
>
> Reviewed-by: Tariq Toukan <[email protected]>
> Thanks for your patch.
>
> Tariq

Applied to net-next-mlx5
Thanks!