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/* 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 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);
}
/* Rx queue */
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_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 */
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