1 files changed, 247 insertions, 0 deletions
diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h
new file mode 100644
index 000000000000..7aa9a535db0e
--- /dev/null
+++ b/net/xdp/xsk_queue.h
@@ -0,0 +1,247 @@
+/* SPDX-License-Identifier: GPL-2.0
+ * XDP user-space ring structure
+ * Copyright(c) 2018 Intel Corporation.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ */
+
+#ifndef _LINUX_XSK_QUEUE_H
+#define _LINUX_XSK_QUEUE_H
+
+#include <linux/types.h>
+#include <linux/if_xdp.h>
+
+#include "xdp_umem_props.h"
+
+#define RX_BATCH_SIZE 16
+
+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_id(struct xsk_queue *q, u32 idx)
+{
+	if (unlikely(idx >= q->umem_props.nframes)) {
+		q->invalid_descs++;
+		return false;
+	}
+	return true;
+}
+
+static inline u32 *xskq_validate_id(struct xsk_queue *q)
+{
+	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;
+
+		if (xskq_is_valid_id(q, ring->desc[idx]))
+			return &ring->desc[idx];
+
+		q->cons_tail++;
+	}
+
+	return NULL;
+}
+
+static inline u32 *xskq_peek_id(struct xsk_queue *q)
+{
+	struct xdp_umem_ring *ring;
+
+	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_id(q);
+	}
+
+	ring = (struct xdp_umem_ring *)q->ring;
+	return &ring->desc[q->cons_tail & q->ring_mask];
+}
+
+static inline void xskq_discard_id(struct xsk_queue *q)
+{
+	q->cons_tail++;
+	(void)xskq_validate_id(q);
+}
+
+static inline int xskq_produce_id(struct xsk_queue *q, u32 id)
+{
+	struct xdp_umem_ring *ring = (struct xdp_umem_ring *)q->ring;
+
+	ring->desc[q->prod_tail++ & q->ring_mask] = id;
+
+	/* Order producer and data */
+	smp_wmb();
+
+	WRITE_ONCE(q->ring->producer, q->prod_tail);
+	return 0;
+}
+
+static inline int xskq_reserve_id(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)
+{
+	u32 buff_len;
+
+	if (unlikely(d->idx >= q->umem_props.nframes)) {
+		q->invalid_descs++;
+		return false;
+	}
+
+	buff_len = q->umem_props.frame_size;
+	if (unlikely(d->len > buff_len || d->len == 0 ||
+		     d->offset > buff_len || d->offset + d->len > buff_len)) {
+		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;
+
+		if (xskq_is_valid_desc(q, &ring->desc[idx])) {
+			if (desc)
+				*desc = ring->desc[idx];
+			return desc;
+		}
+
+		q->cons_tail++;
+	}
+
+	return NULL;
+}
+
+static inline struct xdp_desc *xskq_peek_desc(struct xsk_queue *q,
+					      struct xdp_desc *desc)
+{
+	struct xdp_rxtx_ring *ring;
+
+	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);
+	}
+
+	ring = (struct xdp_rxtx_ring *)q->ring;
+	*desc = ring->desc[q->cons_tail & q->ring_mask];
+	return desc;
+}
+
+static inline void xskq_discard_desc(struct xsk_queue *q)
+{
+	q->cons_tail++;
+	(void)xskq_validate_desc(q, NULL);
+}
+
+static inline int xskq_produce_batch_desc(struct xsk_queue *q,
+					  u32 id, u32 len, u16 offset)
+{
+	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].idx = id;
+	ring->desc[idx].len = len;
+	ring->desc[idx].offset = offset;
+
+	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)
+{
+	return (xskq_nb_avail(q, q->nentries) == q->nentries);
+}
+
+static inline bool xskq_empty_desc(struct xsk_queue *q)
+{
+	return (xskq_nb_free(q, q->prod_tail, 1) == q->nentries);
+}
+
+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 */