diff mbox series

[v2,next] net/mlx5e: Avoid a hundred -Wflex-array-member-not-at-end warnings

Message ID Z76FE8oZO2Ssuj9T@kspp (mailing list archive)
State Superseded
Delegated to: Netdev Maintainers
Headers show
Series [v2,next] net/mlx5e: Avoid a hundred -Wflex-array-member-not-at-end warnings | expand

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Context Check Description
netdev/series_format warning Single patches do not need cover letters; Target tree name not specified in the subject
netdev/tree_selection success Guessed tree name to be net-next
netdev/ynl success Generated files up to date; no warnings/errors; no diff in generated;
netdev/fixes_present success Fixes tag not required for -next series
netdev/header_inline success No static functions without inline keyword in header files
netdev/build_32bit success Errors and warnings before: 0 this patch: 0
netdev/build_tools success No tools touched, skip
netdev/cc_maintainers warning 1 maintainers not CCed: aleksander.lobakin@intel.com
netdev/build_clang success Errors and warnings before: 0 this patch: 0
netdev/verify_signedoff success Signed-off-by tag matches author and committer
netdev/deprecated_api success None detected
netdev/check_selftest success No net selftest shell script
netdev/verify_fixes success No Fixes tag
netdev/build_allmodconfig_warn success Errors and warnings before: 1 this patch: 1
netdev/checkpatch warning CHECK: Please use a blank line after function/struct/union/enum declarations WARNING: line length of 83 exceeds 80 columns WARNING: line length of 84 exceeds 80 columns WARNING: line length of 94 exceeds 80 columns
netdev/build_clang_rust success No Rust files in patch. Skipping build
netdev/kdoc success Errors and warnings before: 0 this patch: 0
netdev/source_inline success Was 0 now: 0

Commit Message

Gustavo A. R. Silva Feb. 26, 2025, 3:05 a.m. UTC
-Wflex-array-member-not-at-end was introduced in GCC-14, and we are
getting ready to enable it, globally.

So, in this particular case, we create a new `struct mlx5e_umr_wqe_hdr`
to enclose the header part of flexible structure `struct mlx5e_umr_wqe`.
This is, all the members except the flexible arrays `inline_mtts`,
`inline_klms` and `inline_ksms` in the anonymous union. We then replace
the header part with `struct mlx5e_umr_wqe_hdr hdr;` in `struct
mlx5e_umr_wqe`, and change the type of the object currently causing
trouble `umr_wqe` from `struct mlx5e_umr_wqe` to `struct
mlx5e_umr_wqe_hdr` --this last bit gets rid of the flex-array-in-the-middle
part and avoid the warnings.

Also, no new members should be added to `struct mlx5e_umr_wqe`, instead
any new members must be included in the header structure `struct
mlx5e_umr_wqe_hdr`. To enforce this, we use `static_assert()`, ensuring
that the memory layout of both the flexible structure and the newly
created header struct remain consistent.

The next step is to refactor the rest of the related code accordingly,
which means adding a bunch of `hdr.` wherever needed.

Lastly, we use `container_of()` whenever we need to retrieve a pointer
to the flexible structure `struct mlx5e_umr_wqe`.

So, with these changes, fix 125 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@kernel.org>
---
Changes in v2:
 - Split the header members of `struct mlx5e_umr_wqe` into a
   separate `struct mlx5e_umr_wqe_hdr`, and refactor the code
   accordingly. (Jakub)
 - Update the changelog text.
 - Also, this part is intentionally left as-is (to keep the assertion
   as close as possible to the flex struct):

| CHECK: Please use a blank line after function/struct/union/enum declarations
| #63: FILE: drivers/net/ethernet/mellanox/mlx5/core/en.h:249:
| };
| +static_assert(offsetof(struct mlx5e_umr_wqe, inline_mtts) == sizeof(struct mlx5e_umr_wqe_hdr),

v1:
 - Link: https://lore.kernel.org/linux-hardening/Z6GCJY8G9EzASrwQ@kspp/

 drivers/net/ethernet/mellanox/mlx5/core/en.h  | 10 +++++++--
 .../ethernet/mellanox/mlx5/core/en/xsk/rx.c   |  6 ++---
 .../net/ethernet/mellanox/mlx5/core/en_main.c |  8 ++++---
 .../net/ethernet/mellanox/mlx5/core/en_rx.c   | 22 +++++++++----------
 4 files changed, 27 insertions(+), 19 deletions(-)
diff mbox series

Patch

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h b/drivers/net/ethernet/mellanox/mlx5/core/en.h
index 979fc56205e1..0e8f4ace8b87 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en.h
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en.h
@@ -232,16 +232,22 @@  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);
 		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 +666,7 @@  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 2fdc86432ac0..9abc6ce13ac9 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;