net/mlx5e: RX, Remove alloc unit layout constraint for legacy rq

The mlx5e_alloc_unit union is conveniently used to store arrays of
pointers to struct page or struct xdp_buff (for xsk). The union is
currently expected to have the size of a pointer for xsk batch
allocations to work. This is conveniet for the current state of the
code but makes it impossible to add a structure of a different size
to the alloc unit.

A further patch in the series will add the mlx5e_frag_page struct for
which the described size constraint will no longer hold.

This change removes the usage of mlx5e_alloc_unit union for legacy rq:

- A union of arrays is introduced (mlx5e_alloc_units) to replace the
  array of unions to allow structures of different sizes.

- Each fragment has a pointer to a unit in the mlx5e_alloc_units array.

Signed-off-by: Dragos Tatulea <dtatulea@nvidia.com>
Reviewed-by: Tariq Toukan <tariqt@nvidia.com>
Signed-off-by: Saeed Mahameed <saeedm@nvidia.com>

1 files changed, 10 insertions, 2 deletions

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h b/drivers/net/ethernet/mellanox/mlx5/core/en.h
index 02237e630d13..32036f23d962 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h
@@ -606,11 +606,19 @@ struct mlx5e_icosq {
 } ____cacheline_aligned_in_smp;
 
 struct mlx5e_wqe_frag_info {
-	union mlx5e_alloc_unit *au;
+	union {
+		struct page **pagep;
+		struct xdp_buff **xskp;
+	};
 	u32 offset;
 	bool last_in_page;
 };
 
+union mlx5e_alloc_units {
+	DECLARE_FLEX_ARRAY(struct page *, pages);
+	DECLARE_FLEX_ARRAY(struct xdp_buff *, xsk_buffs);
+};
+
 struct mlx5e_mpw_info {
 	u16 consumed_strides;
 	DECLARE_BITMAP(xdp_xmit_bitmap, MLX5_MPWRQ_MAX_PAGES_PER_WQE);
@@ -702,7 +710,7 @@ struct mlx5e_rq {
 		struct {
 			struct mlx5_wq_cyc          wq;
 			struct mlx5e_wqe_frag_info *frags;
-			union mlx5e_alloc_unit     *alloc_units;
+			union mlx5e_alloc_units    *alloc_units;
 			struct mlx5e_rq_frags_info  info;
 			mlx5e_fp_skb_from_cqe       skb_from_cqe;
 		} wqe;