On Tue, Mar 5, 2024, at 03:01, Mina Almasry wrote:
> --- a/arch/alpha/include/uapi/asm/socket.h
> +++ b/arch/alpha/include/uapi/asm/socket.h
> #define SO_PEERPIDFD 77
> +#define SO_DEVMEM_LINEAR 79
> +#define SO_DEVMEM_DMABUF 80
> --- a/arch/mips/include/uapi/asm/socket.h
> +++ b/arch/mips/include/uapi/asm/socket.h
> #define SO_PEERPIDFD 77
> +#define SO_DEVMEM_LINEAR 79
> +#define SO_DEVMEM_DMABUF 80
> --- a/arch/parisc/include/uapi/asm/socket.h
> +++ b/arch/parisc/include/uapi/asm/socket.h
> #define SO_PEERPIDFD 0x404B
> +#define SO_DEVMEM_LINEAR 98
> +#define SO_DEVMEM_DMABUF 99
> --- a/arch/sparc/include/uapi/asm/socket.h
> +++ b/arch/sparc/include/uapi/asm/socket.h
> #define SO_PEERPIDFD 0x0056
> +#define SO_DEVMEM_LINEAR 0x0058
> +#define SO_DEVMEM_DMABUF 0x0059
> --- a/include/uapi/asm-generic/socket.h
> +++ b/include/uapi/asm-generic/socket.h
> @@ -135,6 +135,11 @@
> #define SO_PEERPIDFD 77
> +#define SO_DEVMEM_LINEAR 98
> +#define SO_DEVMEM_DMABUF 99
These look inconsistent. I can see how you picked the
alpha and mips numbers, but how did you come up with
the generic and parisc ones? Can you follow the existing
scheme instead?
> diff --git a/include/uapi/linux/uio.h b/include/uapi/linux/uio.h
> index 059b1a9147f4..ad92e37699da 100644
> --- a/include/uapi/linux/uio.h
> +++ b/include/uapi/linux/uio.h
> @@ -20,6 +20,16 @@ struct iovec
> __kernel_size_t iov_len; /* Must be size_t (1003.1g) */
> };
>
> +struct dmabuf_cmsg {
> + __u64 frag_offset; /* offset into the dmabuf where the frag starts.
> + */
> + __u32 frag_size; /* size of the frag. */
> + __u32 frag_token; /* token representing this frag for
> + * DEVMEM_DONTNEED.
> + */
> + __u32 dmabuf_id; /* dmabuf id this frag belongs to. */
> +};
This structure requires a special compat handler to run
x86-32 binaries on x86-64 because of the different alignment
requirements. Any uapi-visible structures should be defined
to avoid this and just have no holes in them. Maybe extend
one of the __u32 members to __u64 or add another 32-bit padding field?
Arnd
