1 files changed, 263 insertions, 0 deletions
diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
new file mode 100644
index 000000000..cf7cbb5dd
--- /dev/null
+++ b/net/xdp/xsk_queue.h
@@ -0,0 +1,263 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* XDP user-space ring structure
+ * Copyright(c) 2018 Intel Corporation.
+ */
+
+#ifndef _LINUX_XSK_QUEUE_H
+#define _LINUX_XSK_QUEUE_H
+
+#include <linux/types.h>
+#include <linux/if_xdp.h>
+#include <net/xdp_sock.h>
+
+#define RX_BATCH_SIZE 16
+#define LAZY_UPDATE_THRESHOLD 128
+
+struct xdp_ring {
+	u32 producer ____cacheline_aligned_in_smp;
+	u32 consumer ____cacheline_aligned_in_smp;
+};
+
+/* Used for the RX and TX queues for packets */
+struct xdp_rxtx_ring {
+	struct xdp_ring ptrs;
+	struct xdp_desc desc[0] ____cacheline_aligned_in_smp;
+};
+
+/* Used for the fill and completion queues for buffers */
+struct xdp_umem_ring {
+	struct xdp_ring ptrs;
+	u64 desc[0] ____cacheline_aligned_in_smp;
+};
+
+struct xsk_queue {
+	struct xdp_umem_props umem_props;
+	u32 ring_mask;
+	u32 nentries;
+	u32 prod_head;
+	u32 prod_tail;
+	u32 cons_head;
+	u32 cons_tail;
+	struct xdp_ring *ring;
+	u64 invalid_descs;
+};
+
+/* Common functions operating for both RXTX and umem queues */
+
+static inline u64 xskq_nb_invalid_descs(struct xsk_queue *q)
+{
+	return q ? q->invalid_descs : 0;
+}
+
+static inline u32 xskq_nb_avail(struct xsk_queue *q, u32 dcnt)
+{
+	u32 entries = q->prod_tail - q->cons_tail;
+
+	if (entries == 0) {
+		/* Refresh the local pointer */
+		q->prod_tail = READ_ONCE(q->ring->producer);
+		entries = q->prod_tail - q->cons_tail;
+	}
+
+	return (entries > dcnt) ? dcnt : entries;
+}
+
+static inline u32 xskq_nb_free(struct xsk_queue *q, u32 producer, u32 dcnt)
+{
+	u32 free_entries = q->nentries - (producer - q->cons_tail);
+
+	if (free_entries >= dcnt)
+		return free_entries;
+
+	/* Refresh the local tail pointer */
+	q->cons_tail = READ_ONCE(q->ring->consumer);
+	return q->nentries - (producer - q->cons_tail);
+}
+
+/* UMEM queue */
+
+static inline bool xskq_is_valid_addr(struct xsk_queue *q, u64 addr)
+{
+	if (addr >= q->umem_props.size) {
+		q->invalid_descs++;
+		return false;
+	}
+
+	return true;
+}
+
+static inline u64 *xskq_validate_addr(struct xsk_queue *q, u64 *addr)
+{
+	while (q->cons_tail != q->cons_head) {
+		struct xdp_umem_ring *ring = (struct xdp_umem_ring *)q->ring;
+		unsigned int idx = q->cons_tail & q->ring_mask;
+
+		*addr = READ_ONCE(ring->desc[idx]) & q->umem_props.chunk_mask;
+		if (xskq_is_valid_addr(q, *addr))
+			return addr;
+
+		q->cons_tail++;
+	}
+
+	return NULL;
+}
+
+static inline u64 *xskq_peek_addr(struct xsk_queue *q, u64 *addr)
+{
+	if (q->cons_tail == q->cons_head) {
+		WRITE_ONCE(q->ring->consumer, q->cons_tail);
+		q->cons_head = q->cons_tail + xskq_nb_avail(q, RX_BATCH_SIZE);
+
+		/* Order consumer and data */
+		smp_rmb();
+	}
+
+	return xskq_validate_addr(q, addr);
+}
+
+static inline void xskq_discard_addr(struct xsk_queue *q)
+{
+	q->cons_tail++;
+}
+
+static inline int xskq_produce_addr(struct xsk_queue *q, u64 addr)
+{
+	struct xdp_umem_ring *ring = (struct xdp_umem_ring *)q->ring;
+
+	if (xskq_nb_free(q, q->prod_tail, 1) == 0)
+		return -ENOSPC;
+
+	ring->desc[q->prod_tail++ & q->ring_mask] = addr;
+
+	/* Order producer and data */
+	smp_wmb();
+
+	WRITE_ONCE(q->ring->producer, q->prod_tail);
+	return 0;
+}
+
+static inline int xskq_produce_addr_lazy(struct xsk_queue *q, u64 addr)
+{
+	struct xdp_umem_ring *ring = (struct xdp_umem_ring *)q->ring;
+
+	if (xskq_nb_free(q, q->prod_head, LAZY_UPDATE_THRESHOLD) == 0)
+		return -ENOSPC;
+
+	ring->desc[q->prod_head++ & q->ring_mask] = addr;
+	return 0;
+}
+
+static inline void xskq_produce_flush_addr_n(struct xsk_queue *q,
+					     u32 nb_entries)
+{
+	/* Order producer and data */
+	smp_wmb();
+
+	q->prod_tail += nb_entries;
+	WRITE_ONCE(q->ring->producer, q->prod_tail);
+}
+
+static inline int xskq_reserve_addr(struct xsk_queue *q)
+{
+	if (xskq_nb_free(q, q->prod_head, 1) == 0)
+		return -ENOSPC;
+
+	q->prod_head++;
+	return 0;
+}
+
+/* Rx/Tx queue */
+
+static inline bool xskq_is_valid_desc(struct xsk_queue *q, struct xdp_desc *d)
+{
+	if (!xskq_is_valid_addr(q, d->addr))
+		return false;
+
+	if (((d->addr + d->len) & q->umem_props.chunk_mask) !=
+	    (d->addr & q->umem_props.chunk_mask)) {
+		q->invalid_descs++;
+		return false;
+	}
+
+	return true;
+}
+
+static inline struct xdp_desc *xskq_validate_desc(struct xsk_queue *q,
+						  struct xdp_desc *desc)
+{
+	while (q->cons_tail != q->cons_head) {
+		struct xdp_rxtx_ring *ring = (struct xdp_rxtx_ring *)q->ring;
+		unsigned int idx = q->cons_tail & q->ring_mask;
+
+		*desc = READ_ONCE(ring->desc[idx]);
+		if (xskq_is_valid_desc(q, desc))
+			return desc;
+
+		q->cons_tail++;
+	}
+
+	return NULL;
+}
+
+static inline struct xdp_desc *xskq_peek_desc(struct xsk_queue *q,
+					      struct xdp_desc *desc)
+{
+	if (q->cons_tail == q->cons_head) {
+		WRITE_ONCE(q->ring->consumer, q->cons_tail);
+		q->cons_head = q->cons_tail + xskq_nb_avail(q, RX_BATCH_SIZE);
+
+		/* Order consumer and data */
+		smp_rmb();
+	}
+
+	return xskq_validate_desc(q, desc);
+}
+
+static inline void xskq_discard_desc(struct xsk_queue *q)
+{
+	q->cons_tail++;
+}
+
+static inline int xskq_produce_batch_desc(struct xsk_queue *q,
+					  u64 addr, u32 len)
+{
+	struct xdp_rxtx_ring *ring = (struct xdp_rxtx_ring *)q->ring;
+	unsigned int idx;
+
+	if (xskq_nb_free(q, q->prod_head, 1) == 0)
+		return -ENOSPC;
+
+	idx = (q->prod_head++) & q->ring_mask;
+	ring->desc[idx].addr = addr;
+	ring->desc[idx].len = len;
+
+	return 0;
+}
+
+static inline void xskq_produce_flush_desc(struct xsk_queue *q)
+{
+	/* Order producer and data */
+	smp_wmb();
+
+	q->prod_tail = q->prod_head;
+	WRITE_ONCE(q->ring->producer, q->prod_tail);
+}
+
+static inline bool xskq_full_desc(struct xsk_queue *q)
+{
+	/* No barriers needed since data is not accessed */
+	return READ_ONCE(q->ring->producer) - READ_ONCE(q->ring->consumer) ==
+		q->nentries;
+}
+
+static inline bool xskq_empty_desc(struct xsk_queue *q)
+{
+	/* No barriers needed since data is not accessed */
+	return READ_ONCE(q->ring->consumer) == READ_ONCE(q->ring->producer);
+}
+
+void xskq_set_umem(struct xsk_queue *q, struct xdp_umem_props *umem_props);
+struct xsk_queue *xskq_create(u32 nentries, bool umem_queue);
+void xskq_destroy(struct xsk_queue *q_ops);
+
+#endif /* _LINUX_XSK_QUEUE_H */