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-rw-r--r--tools/lib/bpf/xsk.h13
1 files changed, 11 insertions, 2 deletions
diff --git a/tools/lib/bpf/xsk.h b/tools/lib/bpf/xsk.h
index a497f00e2962..1b35c40dff73 100644
--- a/tools/lib/bpf/xsk.h
+++ b/tools/lib/bpf/xsk.h
@@ -36,6 +36,10 @@ struct name { \
DEFINE_XSK_RING(xsk_ring_prod);
DEFINE_XSK_RING(xsk_ring_cons);
+/* For a detailed explanation on the memory barriers associated with the
+ * ring, please take a look at net/xdp/xsk_queue.h.
+ */
+
struct xsk_umem;
struct xsk_socket;
@@ -116,8 +120,8 @@ static inline size_t xsk_ring_prod__reserve(struct xsk_ring_prod *prod,
static inline void xsk_ring_prod__submit(struct xsk_ring_prod *prod, size_t nb)
{
- /* Make sure everything has been written to the ring before signalling
- * this to the kernel.
+ /* Make sure everything has been written to the ring before indicating
+ * this to the kernel by writing the producer pointer.
*/
smp_wmb();
@@ -144,6 +148,11 @@ static inline size_t xsk_ring_cons__peek(struct xsk_ring_cons *cons,
static inline void xsk_ring_cons__release(struct xsk_ring_cons *cons, size_t nb)
{
+ /* Make sure data has been read before indicating we are done
+ * with the entries by updating the consumer pointer.
+ */
+ smp_mb();
+
*cons->consumer += nb;
}