On 5/29/2018 10:56 PM, Jason Gunthorpe wrote:
On Tue, May 29, 2018 at 04:09:15PM +0300, Leon Romanovsky wrote:
diff --git a/include/uapi/rdma/mlx5-abi.h b/include/uapi/rdma/mlx5-abi.h
index 508ea8c82da7..ef3f430a7050 100644
+++ b/include/uapi/rdma/mlx5-abi.h
@@ -443,4 +443,18 @@ enum {
enum {
MLX5_IB_CLOCK_INFO_V1 = 0,
};
+
+struct mlx5_ib_flow_counters_data {
+ __aligned_u64 counters_data;
+ __u32 ncounters;
+ __u32 reserved;
+};
+
+struct mlx5_ib_create_flow {
+ __u32 ncounters_data;
+ __u32 reserved;
+ /* Following are counters data based on ncounters_data */
+ struct mlx5_ib_flow_counters_data data[];
+};
+
#endif /* MLX5_ABI_USER_H */
This uapi thing still needs to be fixed as I pointed out before.
In V3 we can go with below, no change in memory layout but it can
clarify the code/usage.
struct mlx5_ib_flow_counters_desc {
__u32 description;
__u32 index;
};
struct mlx5_ib_flow_counters_data {
RDMA_UAPI_PTR(struct mlx5_ib_flow_counters_desc *, counters_data);
__u32 ncounters;
__u32 reserved;
};
struct mlx5_ib_create_flow {
__u32 ncounters_data;
__u32 reserved;
/* Following are counters data based on ncounters_data */
struct mlx5_ib_flow_counters_data data[];
I still can't figure out why this should be a 2d array.
This comes to support the future case of multiple counters objects/specs
passed with the same flow. There is a need to differentiate mapping data
for each counters object and that is done via the 'ncounters_data' field
and the 2d array.
I think it
should be written simply as:
struct mlx5_ib_flow_counter_desc {
__u32 description;
__u32 index;
};
struct mlx5_ib_create_flow {
RDMA_UAPI_PTR(struct mlx5_ib_flow_counter_desc, counters_data);
__u32 ncounters;
__u32 reserved;
};
With the corresponding changes elsewhere.
This doesn't support the above use case.
A flex array at the end of a struct means that the struct can never be
extended again which seems like a terrible idea,
The header [1] has a fixed size and will always exist even if there will
be no counters. Future extensions [2] will be added in the memory post
the flex array which its size depends on 'ncounters_data'. This pattern
is used also in other extended APIs. [3]
struct mlx5_ib_create_flow {
__u32 ncounters_data;
__u32 reserved;
[1] /* Header is above ********
/* Following are counters data based on ncounters_data */
struct mlx5_ib_flow_counters_data data[];
[2] Future fields.
[3]
https://elixir.bootlin.com/linux/latest/source/include/uapi/rdma/ib_user_verbs.h#L1145
