1 /* 2 * Copyright 2006, Red Hat, Inc., Dave Jones 3 * Released under the General Public License (GPL). 4 * 5 * This file contains the linked list implementations for 6 * DEBUG_LIST. 7 */ 8 9 #include <linux/export.h> 10 #include <linux/list.h> 11 #include <linux/bug.h> 12 #include <linux/kernel.h> 13 #include <linux/rculist.h> 14 15 /* 16 * Insert a new entry between two known consecutive entries. 17 * 18 * This is only for internal list manipulation where we know 19 * the prev/next entries already! 20 */ 21 22 void __list_add(struct list_head *new, 23 struct list_head *prev, 24 struct list_head *next) 25 { 26 WARN(next->prev != prev, 27 "list_add corruption. next->prev should be " 28 "prev (%p), but was %p. (next=%p).\n", 29 prev, next->prev, next); 30 WARN(prev->next != next, 31 "list_add corruption. prev->next should be " 32 "next (%p), but was %p. (prev=%p).\n", 33 next, prev->next, prev); 34 WARN(new == prev || new == next, 35 "list_add double add: new=%p, prev=%p, next=%p.\n", 36 new, prev, next); 37 next->prev = new; 38 new->next = next; 39 new->prev = prev; 40 WRITE_ONCE(prev->next, new); 41 } 42 EXPORT_SYMBOL(__list_add); 43 44 void __list_del_entry(struct list_head *entry) 45 { 46 struct list_head *prev, *next; 47 48 prev = entry->prev; 49 next = entry->next; 50 51 if (WARN(next == LIST_POISON1, 52 "list_del corruption, %p->next is LIST_POISON1 (%p)\n", 53 entry, LIST_POISON1) || 54 WARN(prev == LIST_POISON2, 55 "list_del corruption, %p->prev is LIST_POISON2 (%p)\n", 56 entry, LIST_POISON2) || 57 WARN(prev->next != entry, 58 "list_del corruption. prev->next should be %p, " 59 "but was %p\n", entry, prev->next) || 60 WARN(next->prev != entry, 61 "list_del corruption. next->prev should be %p, " 62 "but was %p\n", entry, next->prev)) 63 return; 64 65 __list_del(prev, next); 66 } 67 EXPORT_SYMBOL(__list_del_entry); 68 69 /** 70 * list_del - deletes entry from list. 71 * @entry: the element to delete from the list. 72 * Note: list_empty on entry does not return true after this, the entry is 73 * in an undefined state. 74 */ 75 void list_del(struct list_head *entry) 76 { 77 __list_del_entry(entry); 78 entry->next = LIST_POISON1; 79 entry->prev = LIST_POISON2; 80 } 81 EXPORT_SYMBOL(list_del); 82 83 /* 84 * RCU variants. 85 */ 86 void __list_add_rcu(struct list_head *new, 87 struct list_head *prev, struct list_head *next) 88 { 89 WARN(next->prev != prev, 90 "list_add_rcu corruption. next->prev should be prev (%p), but was %p. (next=%p).\n", 91 prev, next->prev, next); 92 WARN(prev->next != next, 93 "list_add_rcu corruption. prev->next should be next (%p), but was %p. (prev=%p).\n", 94 next, prev->next, prev); 95 new->next = next; 96 new->prev = prev; 97 rcu_assign_pointer(list_next_rcu(prev), new); 98 next->prev = new; 99 } 100 EXPORT_SYMBOL(__list_add_rcu); 101