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authorMartin Kelly <martin.kelly@crowdstrike.com>2023-09-25 23:50:36 +0200
committerAndrii Nakryiko <andrii@kernel.org>2023-09-26 01:22:42 +0200
commit059a8c0c5acd37ecfa64f1832e8765d30f253ce8 (patch)
tree121e16ee53c4f30fdcac2e5452510c153c6ce7aa /tools/lib
parentselftests/bpf: Add tests for ring_buffer__ring (diff)
downloadlinux-059a8c0c5acd37ecfa64f1832e8765d30f253ce8.tar.xz
linux-059a8c0c5acd37ecfa64f1832e8765d30f253ce8.zip
libbpf: Add ring__producer_pos, ring__consumer_pos
Add APIs to get the producer and consumer position for a given ringbuffer. Signed-off-by: Martin Kelly <martin.kelly@crowdstrike.com> Signed-off-by: Andrii Nakryiko <andrii@kernel.org> Link: https://lore.kernel.org/bpf/20230925215045.2375758-6-martin.kelly@crowdstrike.com
Diffstat (limited to 'tools/lib')
-rw-r--r--tools/lib/bpf/libbpf.h18
-rw-r--r--tools/lib/bpf/libbpf.map2
-rw-r--r--tools/lib/bpf/ringbuf.c14
3 files changed, 34 insertions, 0 deletions
diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
index de3ef59b9641..ab470179b7fe 100644
--- a/tools/lib/bpf/libbpf.h
+++ b/tools/lib/bpf/libbpf.h
@@ -1264,6 +1264,24 @@ LIBBPF_API int ring_buffer__epoll_fd(const struct ring_buffer *rb);
LIBBPF_API struct ring *ring_buffer__ring(struct ring_buffer *rb,
unsigned int idx);
+/**
+ * @brief **ring__consumer_pos()** returns the current consumer position in the
+ * given ringbuffer.
+ *
+ * @param r A ringbuffer object.
+ * @return The current consumer position.
+ */
+LIBBPF_API unsigned long ring__consumer_pos(const struct ring *r);
+
+/**
+ * @brief **ring__producer_pos()** returns the current producer position in the
+ * given ringbuffer.
+ *
+ * @param r A ringbuffer object.
+ * @return The current producer position.
+ */
+LIBBPF_API unsigned long ring__producer_pos(const struct ring *r);
+
struct user_ring_buffer_opts {
size_t sz; /* size of this struct, for forward/backward compatibility */
};
diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
index 7a7370c2bc25..3bec002449d5 100644
--- a/tools/lib/bpf/libbpf.map
+++ b/tools/lib/bpf/libbpf.map
@@ -400,5 +400,7 @@ LIBBPF_1.3.0 {
bpf_program__attach_netfilter;
bpf_program__attach_tcx;
bpf_program__attach_uprobe_multi;
+ ring__consumer_pos;
+ ring__producer_pos;
ring_buffer__ring;
} LIBBPF_1.2.0;
diff --git a/tools/lib/bpf/ringbuf.c b/tools/lib/bpf/ringbuf.c
index efde453395b0..d14a607f6b66 100644
--- a/tools/lib/bpf/ringbuf.c
+++ b/tools/lib/bpf/ringbuf.c
@@ -338,6 +338,20 @@ struct ring *ring_buffer__ring(struct ring_buffer *rb, unsigned int idx)
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);
+}
+
static void user_ringbuf_unmap_ring(struct user_ring_buffer *rb)
{
if (rb->consumer_pos) {