Hi,
On 04/02/25 13:27, Gustavo A. R. Silva wrote:
-Wflex-array-member-not-at-end was introduced in GCC-14, and we are
getting ready to enable it, globally.
So, in order to avoid ending up with a flexible-array member in the
middle of other structs, we use the `struct_group_tagged()` helper
to create a new tagged `struct mlx5e_umr_wqe_hdr`. This structure
groups together all the members of the flexible `struct mlx5e_umr_wqe`
except the flexible array.
As a result, the array is effectively separated from the rest of the
members without modifying the memory layout of the flexible structure.
We then change the type of the middle struct member currently causing
trouble from `struct mlx5e_umr_wqe` to `struct mlx5e_umr_wqe_hdr`.
We also want to ensure that when new members need to be added to the
flexible structure, they are always included within the newly created
tagged struct. For this, we use `static_assert()`. This ensures that the
memory layout for both the flexible structure and the new tagged struct
is the same after any changes.
This approach avoids having to implement `struct mlx5e_umr_wqe_hdr` as
a completely separate structure, thus preventing having to maintain two
independent but basically identical structures, closing the door to
potential bugs in the future.
We also use `container_of()` whenever we need to retrieve a pointer to
the flexible structure, through which we can access the flexible-array
member, if necessary.
So, with these changes, fix 124 of the following warnings:
drivers/net/ethernet/mellanox/mlx5/core/en.h:664:48: warning: structure containing a flexible array member is not at the end of another structure [-Wflex-array-member-not-at-end]
Signed-off-by: Gustavo A. R. Silva <gustavoars@xxxxxxxxxx>
---
drivers/net/ethernet/mellanox/mlx5/core/en.h | 13 +++++++++----
drivers/net/ethernet/mellanox/mlx5/core/en_main.c | 4 +++-
2 files changed, 12 insertions(+), 5 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h b/drivers/net/ethernet/mellanox/mlx5/core/en.h
index 979fc56205e1..c30c64eb346f 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h
@@ -233,15 +233,20 @@ struct mlx5e_rx_wqe_cyc {
};
struct mlx5e_umr_wqe {
- struct mlx5_wqe_ctrl_seg ctrl;
- struct mlx5_wqe_umr_ctrl_seg uctrl;
- struct mlx5_mkey_seg mkc;
+ /* New members MUST be added within the struct_group() macro below. */
+ struct_group_tagged(mlx5e_umr_wqe_hdr, hdr,
+ struct mlx5_wqe_ctrl_seg ctrl;
+ struct mlx5_wqe_umr_ctrl_seg uctrl;
+ struct mlx5_mkey_seg mkc;
+ );
union {
DECLARE_FLEX_ARRAY(struct mlx5_mtt, inline_mtts);
DECLARE_FLEX_ARRAY(struct mlx5_klm, inline_klms);
DECLARE_FLEX_ARRAY(struct mlx5_ksm, inline_ksms);
};
};
+static_assert(offsetof(struct mlx5e_umr_wqe, inline_mtts) == sizeof(struct mlx5e_umr_wqe_hdr),
+ "struct member likely outside of struct_group_tagged()");
enum mlx5e_priv_flag {
MLX5E_PFLAG_RX_CQE_BASED_MODER,
@@ -660,7 +665,7 @@ struct mlx5e_rq {
} wqe;
struct {
struct mlx5_wq_ll wq;
- struct mlx5e_umr_wqe umr_wqe;
+ struct mlx5e_umr_wqe_hdr umr_wqe;
struct mlx5e_mpw_info *info;
mlx5e_fp_skb_from_cqe_mpwrq skb_from_cqe_mpwrq;
__be32 umr_mkey_be;
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index bd41b75d246e..4ff4ff2342cf 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -373,6 +373,8 @@ static void mlx5e_rq_shampo_hd_info_free(struct mlx5e_rq *rq)
static int mlx5e_rq_alloc_mpwqe_info(struct mlx5e_rq *rq, int node)
{
+ struct mlx5e_umr_wqe *umr_wqe =
+ container_of(&rq->mpwqe.umr_wqe, struct mlx5e_umr_wqe, hdr);
int wq_sz = mlx5_wq_ll_get_size(&rq->mpwqe.wq);
size_t alloc_size;
@@ -393,7 +395,7 @@ static int mlx5e_rq_alloc_mpwqe_info(struct mlx5e_rq *rq, int node)
bitmap_fill(wi->skip_release_bitmap, rq->mpwqe.pages_per_wqe);
}
- mlx5e_build_umr_wqe(rq, rq->icosq, &rq->mpwqe.umr_wqe);
+ mlx5e_build_umr_wqe(rq, rq->icosq, umr_wqe);
return 0;
}
Here is another alternative for this. And similarly to the struct_group_tagged()
change above, no struct members should be added before or after `struct
mlx5e_umr_wqe_hdr hdr;` in `struct mlx5e_umr_wqe`:
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h b/drivers/net/ethernet/mellanox/mlx5/core/en.h
index 979fc56205e1..912b97eeb4d6 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h
@@ -232,10 +232,13 @@ struct mlx5e_rx_wqe_cyc {
DECLARE_FLEX_ARRAY(struct mlx5_wqe_data_seg, data);
};
-struct mlx5e_umr_wqe {
+struct mlx5e_umr_wqe_hdr {
struct mlx5_wqe_ctrl_seg ctrl;
struct mlx5_wqe_umr_ctrl_seg uctrl;
struct mlx5_mkey_seg mkc;
+};
+struct mlx5e_umr_wqe {
+ struct mlx5e_umr_wqe_hdr hdr;
union {
DECLARE_FLEX_ARRAY(struct mlx5_mtt, inline_mtts);
DECLARE_FLEX_ARRAY(struct mlx5_klm, inline_klms);
@@ -660,7 +663,7 @@ struct mlx5e_rq {
} wqe;
struct {
struct mlx5_wq_ll wq;
- struct mlx5e_umr_wqe umr_wqe;
+ struct mlx5e_umr_wqe_hdr umr_wqe;
struct mlx5e_mpw_info *info;
mlx5e_fp_skb_from_cqe_mpwrq skb_from_cqe_mpwrq;
__be32 umr_mkey_be;
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c b/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c
index 1b7132fa70de..2b05536d564a 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en/xsk/rx.c
@@ -123,7 +123,7 @@ int mlx5e_xsk_alloc_rx_mpwqe(struct mlx5e_rq *rq, u16 ix)
bitmap_zero(wi->skip_release_bitmap, rq->mpwqe.pages_per_wqe);
wi->consumed_strides = 0;
- umr_wqe->ctrl.opmod_idx_opcode =
+ umr_wqe->hdr.ctrl.opmod_idx_opcode =
cpu_to_be32((icosq->pc << MLX5_WQE_CTRL_WQE_INDEX_SHIFT) | MLX5_OPCODE_UMR);
/* Optimized for speed: keep in sync with mlx5e_mpwrq_umr_entry_size. */
@@ -134,7 +134,7 @@ int mlx5e_xsk_alloc_rx_mpwqe(struct mlx5e_rq *rq, u16 ix)
offset = offset * sizeof(struct mlx5_klm) * 2 / MLX5_OCTWORD;
else if (unlikely(rq->mpwqe.umr_mode == MLX5E_MPWRQ_UMR_MODE_TRIPLE))
offset = offset * sizeof(struct mlx5_ksm) * 4 / MLX5_OCTWORD;
- umr_wqe->uctrl.xlt_offset = cpu_to_be16(offset);
+ umr_wqe->hdr.uctrl.xlt_offset = cpu_to_be16(offset);
icosq->db.wqe_info[pi] = (struct mlx5e_icosq_wqe_info) {
.wqe_type = MLX5E_ICOSQ_WQE_UMR_RX,
@@ -144,7 +144,7 @@ int mlx5e_xsk_alloc_rx_mpwqe(struct mlx5e_rq *rq, u16 ix)
icosq->pc += rq->mpwqe.umr_wqebbs;
- icosq->doorbell_cseg = &umr_wqe->ctrl;
+ icosq->doorbell_cseg = &umr_wqe->hdr.ctrl;
return 0;
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
index a814b63ed97e..bbd0b888d237 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_main.c
@@ -311,8 +311,8 @@ static inline void mlx5e_build_umr_wqe(struct mlx5e_rq *rq,
struct mlx5e_icosq *sq,
struct mlx5e_umr_wqe *wqe)
{
- struct mlx5_wqe_ctrl_seg *cseg = &wqe->ctrl;
- struct mlx5_wqe_umr_ctrl_seg *ucseg = &wqe->uctrl;
+ struct mlx5_wqe_ctrl_seg *cseg = &wqe->hdr.ctrl;
+ struct mlx5_wqe_umr_ctrl_seg *ucseg = &wqe->hdr.uctrl;
u16 octowords;
u8 ds_cnt;
@@ -393,7 +393,9 @@ static int mlx5e_rq_alloc_mpwqe_info(struct mlx5e_rq *rq, int node)
bitmap_fill(wi->skip_release_bitmap, rq->mpwqe.pages_per_wqe);
}
- mlx5e_build_umr_wqe(rq, rq->icosq, &rq->mpwqe.umr_wqe);
+ mlx5e_build_umr_wqe(rq, rq->icosq,
+ container_of(&rq->mpwqe.umr_wqe,
+ struct mlx5e_umr_wqe, hdr));
return 0;
}
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
index 1963bc5adb18..5fd70b4d55be 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rx.c
@@ -631,16 +631,16 @@ static void build_ksm_umr(struct mlx5e_icosq *sq, struct mlx5e_umr_wqe *umr_wqe,
__be32 key, u16 offset, u16 ksm_len)
{
memset(umr_wqe, 0, offsetof(struct mlx5e_umr_wqe, inline_ksms));
- umr_wqe->ctrl.opmod_idx_opcode =
+ umr_wqe->hdr.ctrl.opmod_idx_opcode =
cpu_to_be32((sq->pc << MLX5_WQE_CTRL_WQE_INDEX_SHIFT) |
MLX5_OPCODE_UMR);
- umr_wqe->ctrl.umr_mkey = key;
- umr_wqe->ctrl.qpn_ds = cpu_to_be32((sq->sqn << MLX5_WQE_CTRL_QPN_SHIFT)
+ umr_wqe->hdr.ctrl.umr_mkey = key;
+ umr_wqe->hdr.ctrl.qpn_ds = cpu_to_be32((sq->sqn << MLX5_WQE_CTRL_QPN_SHIFT)
| MLX5E_KSM_UMR_DS_CNT(ksm_len));
- umr_wqe->uctrl.flags = MLX5_UMR_TRANSLATION_OFFSET_EN | MLX5_UMR_INLINE;
- umr_wqe->uctrl.xlt_offset = cpu_to_be16(offset);
- umr_wqe->uctrl.xlt_octowords = cpu_to_be16(ksm_len);
- umr_wqe->uctrl.mkey_mask = cpu_to_be64(MLX5_MKEY_MASK_FREE);
+ umr_wqe->hdr.uctrl.flags = MLX5_UMR_TRANSLATION_OFFSET_EN | MLX5_UMR_INLINE;
+ umr_wqe->hdr.uctrl.xlt_offset = cpu_to_be16(offset);
+ umr_wqe->hdr.uctrl.xlt_octowords = cpu_to_be16(ksm_len);
+ umr_wqe->hdr.uctrl.mkey_mask = cpu_to_be64(MLX5_MKEY_MASK_FREE);
}
static struct mlx5e_frag_page *mlx5e_shampo_hd_to_frag_page(struct mlx5e_rq *rq, int header_index)
@@ -704,7 +704,7 @@ static int mlx5e_build_shampo_hd_umr(struct mlx5e_rq *rq,
shampo->pi = (shampo->pi + ksm_entries) & (shampo->hd_per_wq - 1);
sq->pc += wqe_bbs;
- sq->doorbell_cseg = &umr_wqe->ctrl;
+ sq->doorbell_cseg = &umr_wqe->hdr.ctrl;
return 0;
@@ -814,12 +814,12 @@ static int mlx5e_alloc_rx_mpwqe(struct mlx5e_rq *rq, u16 ix)
bitmap_zero(wi->skip_release_bitmap, rq->mpwqe.pages_per_wqe);
wi->consumed_strides = 0;
- umr_wqe->ctrl.opmod_idx_opcode =
+ umr_wqe->hdr.ctrl.opmod_idx_opcode =
cpu_to_be32((sq->pc << MLX5_WQE_CTRL_WQE_INDEX_SHIFT) |
MLX5_OPCODE_UMR);
offset = (ix * rq->mpwqe.mtts_per_wqe) * sizeof(struct mlx5_mtt) / MLX5_OCTWORD;
- umr_wqe->uctrl.xlt_offset = cpu_to_be16(offset);
+ umr_wqe->hdr.uctrl.xlt_offset = cpu_to_be16(offset);
sq->db.wqe_info[pi] = (struct mlx5e_icosq_wqe_info) {
.wqe_type = MLX5E_ICOSQ_WQE_UMR_RX,
@@ -829,7 +829,7 @@ static int mlx5e_alloc_rx_mpwqe(struct mlx5e_rq *rq, u16 ix)
sq->pc += rq->mpwqe.umr_wqebbs;
- sq->doorbell_cseg = &umr_wqe->ctrl;
+ sq->doorbell_cseg = &umr_wqe->hdr.ctrl;
return 0;
Thanks
--
Gustavo
