1 /* 2 * Copyright (c) 2019-2020 Jonathan Gray <jsg@openbsd.org> 3 * Copyright (c) 2020 François Tigeot <ftigeot@wolfpond.org> 4 * 5 * Permission is hereby granted, free of charge, to any person obtaining a 6 * copy of this software and associated documentation files (the "Software"), 7 * to deal in the Software without restriction, including without limitation 8 * the rights to use, copy, modify, merge, publish, distribute, sublicense, 9 * and/or sell copies of the Software, and to permit persons to whom the 10 * Software is furnished to do so, subject to the following conditions: 11 * 12 * The above copyright notice and this permission notice (including the next 13 * paragraph) shall be included in all copies or substantial portions of the 14 * Software. 15 * 16 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR 17 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, 18 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL 19 * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER 20 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, 21 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE 22 * SOFTWARE. 23 */ 24 25 #ifndef _LINUX_LLIST_H_ 26 #define _LINUX_LLIST_H_ 27 28 #include <linux/atomic.h> 29 #include <linux/kernel.h> 30 31 struct llist_node { 32 struct llist_node *next; 33 }; 34 35 struct llist_head { 36 struct llist_node *first; 37 }; 38 39 #define llist_entry(ptr, type, member) \ 40 ((ptr) ? container_of(ptr, type, member) : NULL) 41 42 static inline struct llist_node * 43 llist_del_all(struct llist_head *head) 44 { 45 return atomic_swap_ptr((void *)&head->first, NULL); 46 } 47 48 static inline struct llist_node * 49 llist_del_first(struct llist_head *head) 50 { 51 struct llist_node *first, *next; 52 53 do { 54 first = head->first; 55 if (first == NULL) 56 return NULL; 57 next = first->next; 58 } while (atomic_cas_ptr(&head->first, first, next) != first); 59 60 return first; 61 } 62 63 static inline bool 64 llist_add(struct llist_node *new, struct llist_head *head) 65 { 66 struct llist_node *first = READ_ONCE(head->first); 67 68 do { 69 new->next = first; 70 } while (cmpxchg(&head->first, first, new) != first); 71 72 return (first == NULL); 73 } 74 75 static inline void 76 init_llist_head(struct llist_head *head) 77 { 78 head->first = NULL; 79 } 80 81 static inline bool 82 llist_empty(struct llist_head *head) 83 { 84 return (head->first == NULL); 85 } 86 87 #define llist_for_each_entry_safe(pos, n, node, member) \ 88 for (pos = llist_entry((node), __typeof(*pos), member); \ 89 pos != NULL && \ 90 (n = llist_entry(pos->member.next, __typeof(*pos), member), pos); \ 91 pos = n) 92 93 #define llist_for_each_entry(pos, node, member) \ 94 for ((pos) = llist_entry((node), __typeof(*(pos)), member); \ 95 (pos) != NULL; \ 96 (pos) = llist_entry((pos)->member.next, __typeof(*(pos)), member)) 97 98 #endif /* _LINUX_LLIST_H_ */ 99