On 26 Feb 13:47, 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 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@xxxxxxxxxx> --- Changes in v3: - Update error message in the assertion. - 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), 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. - Link: https://lore.kernel.org/linux-hardening/Z76FE8oZO2Ssuj9T@kspp/ 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 --git a/drivers/net/ethernet/mellanox/mlx5/core/en.h b/drivers/net/ethernet/mellanox/mlx5/core/en.h index 979fc56205e1..90de40521029 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;
You missed or ignored my comment on v0, anyway: Can we have struct mlx5e_umr_wq_hdr defined anonymously within mlx5e_umr_wqe? Let's avoid namespace pollution.
