1 files changed, 72 insertions, 13 deletions

diff --git a/tools/lib/bpf/ringbuf.c b/tools/lib/bpf/ringbuf.c
index 02199364db13..aacb64278a01 100644
--- a/tools/lib/bpf/ringbuf.c
+++ b/tools/lib/bpf/ringbuf.c
@@ -34,7 +34,7 @@ struct ring {
 
 struct ring_buffer {
 	struct epoll_event *events;
-	struct ring *rings;
+	struct ring **rings;
 	size_t page_size;
 	int epoll_fd;
 	int ring_cnt;
@@ -57,7 +57,7 @@ struct ringbuf_hdr {
 	__u32 pad;
 };
 
-static void ringbuf_unmap_ring(struct ring_buffer *rb, struct ring *r)
+static void ringbuf_free_ring(struct ring_buffer *rb, struct ring *r)
 {
 	if (r->consumer_pos) {
 		munmap(r->consumer_pos, rb->page_size);
@@ -67,6 +67,8 @@ static void ringbuf_unmap_ring(struct ring_buffer *rb, struct ring *r)
 		munmap(r->producer_pos, rb->page_size + 2 * (r->mask + 1));
 		r->producer_pos = NULL;
 	}
+
+	free(r);
 }
 
 /* Add extra RINGBUF maps to this ring buffer manager */
@@ -107,8 +109,10 @@ int ring_buffer__add(struct ring_buffer *rb, int map_fd,
 		return libbpf_err(-ENOMEM);
 	rb->events = tmp;
 
-	r = &rb->rings[rb->ring_cnt];
-	memset(r, 0, sizeof(*r));
+	r = calloc(1, sizeof(*r));
+	if (!r)
+		return libbpf_err(-ENOMEM);
+	rb->rings[rb->ring_cnt] = r;
 
 	r->map_fd = map_fd;
 	r->sample_cb = sample_cb;
@@ -121,7 +125,7 @@ int ring_buffer__add(struct ring_buffer *rb, int map_fd,
 		err = -errno;
 		pr_warn("ringbuf: failed to mmap consumer page for map fd=%d: %d\n",
 			map_fd, err);
-		return libbpf_err(err);
+		goto err_out;
 	}
 	r->consumer_pos = tmp;
 
@@ -131,16 +135,16 @@ int ring_buffer__add(struct ring_buffer *rb, int map_fd,
 	 */
 	mmap_sz = rb->page_size + 2 * (__u64)info.max_entries;
 	if (mmap_sz != (__u64)(size_t)mmap_sz) {
+		err = -E2BIG;
 		pr_warn("ringbuf: ring buffer size (%u) is too big\n", info.max_entries);
-		return libbpf_err(-E2BIG);
+		goto err_out;
 	}
 	tmp = mmap(NULL, (size_t)mmap_sz, PROT_READ, MAP_SHARED, map_fd, rb->page_size);
 	if (tmp == MAP_FAILED) {
 		err = -errno;
-		ringbuf_unmap_ring(rb, r);
 		pr_warn("ringbuf: failed to mmap data pages for map fd=%d: %d\n",
 			map_fd, err);
-		return libbpf_err(err);
+		goto err_out;
 	}
 	r->producer_pos = tmp;
 	r->data = tmp + rb->page_size;
@@ -152,14 +156,17 @@ int ring_buffer__add(struct ring_buffer *rb, int map_fd,
 	e->data.fd = rb->ring_cnt;
 	if (epoll_ctl(rb->epoll_fd, EPOLL_CTL_ADD, map_fd, e) < 0) {
 		err = -errno;
-		ringbuf_unmap_ring(rb, r);
 		pr_warn("ringbuf: failed to epoll add map fd=%d: %d\n",
 			map_fd, err);
-		return libbpf_err(err);
+		goto err_out;
 	}
 
 	rb->ring_cnt++;
 	return 0;
+
+err_out:
+	ringbuf_free_ring(rb, r);
+	return libbpf_err(err);
 }
 
 void ring_buffer__free(struct ring_buffer *rb)
@@ -170,7 +177,7 @@ void ring_buffer__free(struct ring_buffer *rb)
 		return;
 
 	for (i = 0; i < rb->ring_cnt; ++i)
-		ringbuf_unmap_ring(rb, &rb->rings[i]);
+		ringbuf_free_ring(rb, rb->rings[i]);
 	if (rb->epoll_fd >= 0)
 		close(rb->epoll_fd);
 
@@ -278,7 +285,7 @@ int ring_buffer__consume(struct ring_buffer *rb)
 	int i;
 
 	for (i = 0; i < rb->ring_cnt; i++) {
-		struct ring *ring = &rb->rings[i];
+		struct ring *ring = rb->rings[i];
 
 		err = ringbuf_process_ring(ring);
 		if (err < 0)
@@ -305,7 +312,7 @@ int ring_buffer__poll(struct ring_buffer *rb, int timeout_ms)
 
 	for (i = 0; i < cnt; i++) {
 		__u32 ring_id = rb->events[i].data.fd;
-		struct ring *ring = &rb->rings[ring_id];
+		struct ring *ring = rb->rings[ring_id];
 
 		err = ringbuf_process_ring(ring);
 		if (err < 0)
@@ -323,6 +330,58 @@ int ring_buffer__epoll_fd(const struct ring_buffer *rb)
 	return rb->epoll_fd;
 }
 
+struct ring *ring_buffer__ring(struct ring_buffer *rb, unsigned int idx)
+{
+	if (idx >= rb->ring_cnt)
+		return errno = ERANGE, NULL;
+
+	return rb->rings[idx];
+}
+
+unsigned long ring__consumer_pos(const struct ring *r)
+{
+	/* Synchronizes with smp_store_release() in ringbuf_process_ring(). */
+	return smp_load_acquire(r->consumer_pos);
+}
+
+unsigned long ring__producer_pos(const struct ring *r)
+{
+	/* Synchronizes with smp_store_release() in __bpf_ringbuf_reserve() in
+	 * the kernel.
+	 */
+	return smp_load_acquire(r->producer_pos);
+}
+
+size_t ring__avail_data_size(const struct ring *r)
+{
+	unsigned long cons_pos, prod_pos;
+
+	cons_pos = ring__consumer_pos(r);
+	prod_pos = ring__producer_pos(r);
+	return prod_pos - cons_pos;
+}
+
+size_t ring__size(const struct ring *r)
+{
+	return r->mask + 1;
+}
+
+int ring__map_fd(const struct ring *r)
+{
+	return r->map_fd;
+}
+
+int ring__consume(struct ring *r)
+{
+	int64_t res;
+
+	res = ringbuf_process_ring(r);
+	if (res < 0)
+		return libbpf_err(res);
+
+	return res > INT_MAX ? INT_MAX : res;
+}
+
 static void user_ringbuf_unmap_ring(struct user_ring_buffer *rb)
 {
 	if (rb->consumer_pos) {