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

[Arnd Bergmann]

From: Arnd Bergmann <a...@arndb.de>

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 <a...@arndb.de>
---
 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