On 23/3/26 10:18, Menglong Dong wrote: > Add the testing to access the bpf_ringbuf with the map pointer. > "consumer_pos" and "producer_pos" is accessed in this testing. We reserve > 128 bytes in the ringbuf to test the producer_pos, which should be > "128 + 8", and the "8" is BPF_RINGBUF_HDR_SZ. > > It will be helpful if we want to evaluate the usage of the ringbuf in bpf > prog with the consumer and producer position. >
128 is a plain test for ringbuf, like those in ringbuf_overwrite_mode_subtest(). The reserved size can be 0; however, a test for it is missing. It would be better to add a test against 0-size here or there. > Signed-off-by: Menglong Dong <[email protected]> > Reviewed-by: Emil Tsalapatis <[email protected]> Acked-by: Leon Hwang <[email protected]> One nit below. > --- > v2: > - don't set the max_entries for the ringbuf map > - add comment for the producer_pos > --- > .../testing/selftests/bpf/progs/map_ptr_kern.c | 18 ++++++++++++++++++ > 1 file changed, 18 insertions(+) > > diff --git a/tools/testing/selftests/bpf/progs/map_ptr_kern.c > b/tools/testing/selftests/bpf/progs/map_ptr_kern.c > index efaf622c28dd..d7611e7018ca 100644 > --- a/tools/testing/selftests/bpf/progs/map_ptr_kern.c > +++ b/tools/testing/selftests/bpf/progs/map_ptr_kern.c > @@ -647,8 +647,14 @@ static inline int check_devmap_hash(void) > return 1; > } > > +struct bpf_ringbuf { > + unsigned long consumer_pos; > + unsigned long producer_pos; > +} __attribute__((preserve_access_index)); > + > struct bpf_ringbuf_map { > struct bpf_map map; > + struct bpf_ringbuf *rb; > } __attribute__((preserve_access_index)); > > struct { > @@ -659,9 +665,21 @@ static inline int check_ringbuf(void) > { > struct bpf_ringbuf_map *ringbuf = (struct bpf_ringbuf_map *)&m_ringbuf; > struct bpf_map *map = (struct bpf_map *)&m_ringbuf; > + struct bpf_ringbuf *rb; > + void *ptr; > > VERIFY(check(&ringbuf->map, map, 0, 0, page_size)); > > + ptr = bpf_ringbuf_reserve(&m_ringbuf, 128, 0); > + VERIFY(ptr); > + > + bpf_ringbuf_discard(ptr, 0); > + rb = ringbuf->rb; > + VERIFY(rb); > + VERIFY(rb->consumer_pos == 0); > + /* The "8" here is BPF_RINGBUF_HDR_SZ */ > + VERIFY(rb->producer_pos == 128 + 8); > + NIT: Use BPF_RINGBUF_HDR_SZ directly. Is it missing in vmlinux.h? Thanks, Leon > return 1; > } >
