On Sun, 31 May 2020 23:46:49 +0200
Lorenzo Bianconi <lore...@kernel.org> wrote:
> diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c
> index 57402276d8af..24ab0a6b9772 100644
> --- a/kernel/bpf/cpumap.c
> +++ b/kernel/bpf/cpumap.c
> @@ -51,6 +51,10 @@ struct xdp_bulk_queue {
> /* CPUMAP value */
> struct bpf_cpumap_val {
> u32 qsize; /* queue size */
> + union {
> + int fd; /* program file descriptor */
> + u32 id; /* program id */
> + } prog;
> };
Please name the union 'bpf_prog' and not 'prog'.
We should match what David Ahern did for devmap.
Even-though we are NOT exposing this in the UAPI header-file, this still
becomes a UAPI interface (actually kABI). The struct member names are
still important, even-though this is a binary layout, because the BTF
info is basically documenting this API.
Notice when kernel is compiled with BTF info, you (or end-user) can use
pahole to "reverse" the struct layout (comments don't survive, so we
need descriptive member names):
$ pahole bpf_devmap_val
struct bpf_devmap_val {
__u32 ifindex; /* 0 4 */
union {
int fd; /* 4 4 */
__u32 id; /* 4 4 */
} bpf_prog; /* 4 4 */
struct {
unsigned char data[24]; /* 8 24 */
} storage; /* 8 24 */
/* size: 32, cachelines: 1, members: 3 */
/* last cacheline: 32 bytes */
};
--
Best regards,
Jesper Dangaard Brouer
MSc.CS, Principal Kernel Engineer at Red Hat
LinkedIn: http://www.linkedin.com/in/brouer
$ bpftool btf dump file /sys/kernel/btf/vmlinux format c | grep -A10 'struct
bpf_devmap_val {'
struct bpf_devmap_val {
__u32 ifindex;
union {
int fd;
__u32 id;
} bpf_prog;
struct {
unsigned char data[24];
} storage;
};
