1 /* SPDX-License-Identifier: BSD-3-Clause
3 * Copyright (c) 2010-2020 Intel Corporation
4 * Copyright (c) 2007-2009 Kip Macy kmacy@freebsd.org
6 * Derived from FreeBSD's bufring.h
7 * Used as BSD-3 Licensed with permission from Kip Macy.
10 #ifndef _RTE_RING_PEEK_C11_MEM_H_
11 #define _RTE_RING_PEEK_C11_MEM_H_
14 * @file rte_ring_peek_c11_mem.h
15 * It is not recommended to include this file directly,
16 * include <rte_ring.h> instead.
17 * Contains internal helper functions for rte_ring peek API.
18 * For more information please refer to <rte_ring_peek.h>.
22 * @internal get current tail value.
23 * This function should be used only for single thread producer/consumer.
24 * Check that user didn't request to move tail above the head.
26 * - return zero, that will cause abort any pending changes and
27 * return head to its previous position.
28 * - throw an assert in debug mode.
30 static __rte_always_inline uint32_t
31 __rte_ring_st_get_tail(struct rte_ring_headtail *ht, uint32_t *tail,
41 num = (n >= num) ? num : 0;
48 * @internal set new values for head and tail.
49 * This function should be used only for single thread producer/consumer.
50 * Should be used only in conjunction with __rte_ring_st_get_tail.
52 static __rte_always_inline void
53 __rte_ring_st_set_head_tail(struct rte_ring_headtail *ht, uint32_t tail,
54 uint32_t num, uint32_t enqueue)
58 RTE_SET_USED(enqueue);
62 __atomic_store_n(&ht->tail, pos, __ATOMIC_RELEASE);
66 * @internal get current tail value.
67 * This function should be used only for producer/consumer in MT_HTS mode.
68 * Check that user didn't request to move tail above the head.
70 * - return zero, that will cause abort any pending changes and
71 * return head to its previous position.
72 * - throw an assert in debug mode.
74 static __rte_always_inline uint32_t
75 __rte_ring_hts_get_tail(struct rte_ring_hts_headtail *ht, uint32_t *tail,
79 union __rte_ring_hts_pos p;
81 p.raw = __atomic_load_n(&ht->ht.raw, __ATOMIC_RELAXED);
82 n = p.pos.head - p.pos.tail;
85 num = (n >= num) ? num : 0;
92 * @internal set new values for head and tail as one atomic 64 bit operation.
93 * This function should be used only for producer/consumer in MT_HTS mode.
94 * Should be used only in conjunction with __rte_ring_hts_get_tail.
96 static __rte_always_inline void
97 __rte_ring_hts_set_head_tail(struct rte_ring_hts_headtail *ht, uint32_t tail,
98 uint32_t num, uint32_t enqueue)
100 union __rte_ring_hts_pos p;
102 RTE_SET_USED(enqueue);
104 p.pos.head = tail + num;
105 p.pos.tail = p.pos.head;
107 __atomic_store_n(&ht->ht.raw, p.raw, __ATOMIC_RELEASE);
110 #endif /* _RTE_RING_PEEK_C11_MEM_H_ */