Re: [PATCH][next] RDMA/rxe: Avoid -Wflex-array-member-not-at-end warnings

[Zhu Yanjun]

在 2025/12/18 21:48, Gustavo A. R. Silva 写道:
> > The struct rxe_recv_wqe is as below.
> >
> > struct rxe_recv_wqe {
> >      __aligned_u64       wr_id;
> >      __u32           reserved;
> >      __u32           padding;
> >      struct rxe_dma_info dma;
>
> Expand struct rxe_dma_info here.

Thanks. In struct rxe_dma_info, the struct is

struct rxe_sge {
       __aligned_u64 addr;
       __u32   length;
       __u32   lkey;
};

But in your commit, struct ib_sge is used.

struct ib_sge {
    u64 addr;
    u32 length;
    u32 lkey;
};
__aligned_u64 is a 64-bit integer with a guaranteed 8-byte alignment,

used to preserve ABI correctness across architectures and between

userspace and kernel, while u64 has architecture-dependent alignment.

I am not sure if we can treate "struct rxe_sge" as the same with "struct 
ib_sge".


Leon and Jason, please comment on it.


Yanjun.Zhu

> > };
> >
> > But I can not find dma.sge in the above struct. Can you explain it?
> >
> > To be honest, I read your original commit for several times, but I 
> > can not get it.  Can you explain the MACRO TRAILING_OVERLAP? And how 
> > can it replace the following struct?
>
> This is clearly explained in the changelog text. I think what you're
> missing will be clear once you understand how nested structures
> work. See my comment above.
>
> -Gustavo