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Diffstat (limited to 'tools/lib/bpf/xsk.h')
-rw-r--r--tools/lib/bpf/xsk.h22
1 files changed, 16 insertions, 6 deletions
diff --git a/tools/lib/bpf/xsk.h b/tools/lib/bpf/xsk.h
index a497f00e2962..82ea71a0f3ec 100644
--- a/tools/lib/bpf/xsk.h
+++ b/tools/lib/bpf/xsk.h
@@ -16,6 +16,7 @@
#include <linux/if_xdp.h>
#include "libbpf.h"
+#include "libbpf_util.h"
#ifdef __cplusplus
extern "C" {
@@ -36,6 +37,10 @@ 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;
@@ -105,7 +110,7 @@ static inline __u32 xsk_cons_nb_avail(struct xsk_ring_cons *r, __u32 nb)
static inline size_t xsk_ring_prod__reserve(struct xsk_ring_prod *prod,
size_t nb, __u32 *idx)
{
- if (unlikely(xsk_prod_nb_free(prod, nb) < nb))
+ if (xsk_prod_nb_free(prod, nb) < nb)
return 0;
*idx = prod->cached_prod;
@@ -116,10 +121,10 @@ 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();
+ libbpf_smp_wmb();
*prod->producer += nb;
}
@@ -129,11 +134,11 @@ static inline size_t xsk_ring_cons__peek(struct xsk_ring_cons *cons,
{
size_t entries = xsk_cons_nb_avail(cons, nb);
- if (likely(entries > 0)) {
+ if (entries > 0) {
/* Make sure we do not speculatively read the data before
* we have received the packet buffers from the ring.
*/
- smp_rmb();
+ libbpf_smp_rmb();
*idx = cons->cached_cons;
cons->cached_cons += entries;
@@ -144,6 +149,11 @@ 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.
+ */
+ libbpf_smp_rwmb();
+
*cons->consumer += nb;
}