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b6a37eac MD |
1 | #ifndef _URCU_RCULFSTACK_STATIC_H |
2 | #define _URCU_RCULFSTACK_STATIC_H | |
3 | ||
4 | /* | |
5 | * rculfstack-static.h | |
6 | * | |
7 | * Userspace RCU library - Lock-Free RCU Stack | |
8 | * | |
9 | * Copyright 2010 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
10 | * | |
11 | * TO BE INCLUDED ONLY IN LGPL-COMPATIBLE CODE. See rculfstack.h for linking | |
12 | * dynamically with the userspace rcu library. | |
13 | * | |
14 | * This library is free software; you can redistribute it and/or | |
15 | * modify it under the terms of the GNU Lesser General Public | |
16 | * License as published by the Free Software Foundation; either | |
17 | * version 2.1 of the License, or (at your option) any later version. | |
18 | * | |
19 | * This library is distributed in the hope that it will be useful, | |
20 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
21 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
22 | * Lesser General Public License for more details. | |
23 | * | |
24 | * You should have received a copy of the GNU Lesser General Public | |
25 | * License along with this library; if not, write to the Free Software | |
26 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
27 | */ | |
28 | ||
a2e7bf9c | 29 | #include <urcu/uatomic.h> |
b6a37eac MD |
30 | /* A urcu implementation header should be already included. */ |
31 | ||
32 | #ifdef __cplusplus | |
33 | extern "C" { | |
34 | #endif | |
35 | ||
16aa9ee8 | 36 | void _cds_lfs_node_init_rcu(struct cds_lfs_node_rcu *node) |
b6a37eac MD |
37 | { |
38 | } | |
39 | ||
16aa9ee8 | 40 | void _cds_lfs_init_rcu(struct cds_lfs_stack_rcu *s) |
b6a37eac MD |
41 | { |
42 | s->head = NULL; | |
43 | } | |
44 | ||
16aa9ee8 | 45 | void _cds_lfs_push_rcu(struct cds_lfs_stack_rcu *s, struct cds_lfs_node_rcu *node) |
b6a37eac | 46 | { |
16aa9ee8 | 47 | struct cds_lfs_node_rcu *head = NULL; |
75202035 | 48 | |
b6a37eac | 49 | for (;;) { |
16aa9ee8 | 50 | struct cds_lfs_node_rcu *old_head = head; |
b6a37eac | 51 | |
b6a37eac MD |
52 | node->next = head; |
53 | /* | |
54 | * uatomic_cmpxchg() implicit memory barrier orders earlier | |
55 | * stores to node before publication. | |
56 | */ | |
75202035 MD |
57 | head = uatomic_cmpxchg(&s->head, old_head, node); |
58 | if (old_head == head) | |
59 | break; | |
b6a37eac MD |
60 | } |
61 | } | |
62 | ||
63 | /* | |
d9b52143 MD |
64 | * Should be called under rcu read-side lock. |
65 | * | |
b6a37eac | 66 | * The caller must wait for a grace period to pass before freeing the returned |
16aa9ee8 | 67 | * node or modifying the cds_lfs_node_rcu structure. |
b6a37eac MD |
68 | * Returns NULL if stack is empty. |
69 | */ | |
16aa9ee8 DG |
70 | struct cds_lfs_node_rcu * |
71 | _cds_lfs_pop_rcu(struct cds_lfs_stack_rcu *s) | |
b6a37eac MD |
72 | { |
73 | for (;;) { | |
16aa9ee8 | 74 | struct cds_lfs_node_rcu *head; |
b6a37eac | 75 | |
4fc06b7f MD |
76 | head = rcu_dereference(s->head); |
77 | if (head) { | |
16aa9ee8 | 78 | struct cds_lfs_node_rcu *next = rcu_dereference(head->next); |
b6a37eac | 79 | |
4fc06b7f | 80 | if (uatomic_cmpxchg(&s->head, head, next) == head) { |
4fc06b7f MD |
81 | return head; |
82 | } else { | |
83 | /* Concurrent modification. Retry. */ | |
4fc06b7f MD |
84 | continue; |
85 | } | |
86 | } else { | |
87 | /* Empty stack */ | |
4fc06b7f MD |
88 | return NULL; |
89 | } | |
b6a37eac MD |
90 | } |
91 | } | |
92 | ||
93 | #ifdef __cplusplus | |
94 | } | |
95 | #endif | |
96 | ||
97 | #endif /* _URCU_RCULFSTACK_STATIC_H */ |