Instead of always consuming all items from a ring buffer in a greedy
way, allow to stop when the callback returns a value > 0.
This allows to distinguish between an error condition and an intentional
stop condition by returning a non-negative non-zero value from the ring
buffer callback.
This can be useful, for example, to consume just a single item from the
ring buffer.
Signed-off-by: Andrea Righi <andrea.righi@xxxxxxxxxxxxx>
---
tools/lib/bpf/ringbuf.c | 8 ++++++++
1 file changed, 8 insertions(+)
diff --git a/tools/lib/bpf/ringbuf.c b/tools/lib/bpf/ringbuf.c
index aacb64278a01..dd8908eb3204 100644
--- a/tools/lib/bpf/ringbuf.c
+++ b/tools/lib/bpf/ringbuf.c
@@ -265,6 +265,14 @@ static int64_t ringbuf_process_ring(struct ring *r)
return err;
}
cnt++;
+ if (err > 0) {
+ /* update consumer pos and return the
+ * total amount of items consumed.
+ */
+ smp_store_release(r->consumer_pos,
+ cons_pos);
+ goto done;
+ }
}
smp_store_release(r->consumer_pos, cons_pos);
--
2.43.0
