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 next->prev = new; 35 new->next = next; 36 new->prev = prev; 37 prev->next = new; 38 } 39 EXPORT_SYMBOL(__list_add); 40 41 void __list_del_entry(struct list_head *entry) 42 { 43 struct list_head *prev, *next; 44 45 prev = entry->prev; 46 next = entry->next; 47 48 if (WARN(next == LIST_POISON1, 49 "list_del corruption, %p->next is LIST_POISON1 (%p)\n", 50 entry, LIST_POISON1) || 51 WARN(prev == LIST_POISON2, 52 "list_del corruption, %p->prev is LIST_POISON2 (%p)\n", 53 entry, LIST_POISON2) || 54 WARN(prev->next != entry, 55 "list_del corruption. prev->next should be %p, " 56 "but was %p\n", entry, prev->next) || 57 WARN(next->prev != entry, 58 "list_del corruption. next->prev should be %p, " 59 "but was %p\n", entry, next->prev)) 60 return; 61 62 __list_del(prev, next); 63 } 64 EXPORT_SYMBOL(__list_del_entry); 65 66 /** 67 * list_del - deletes entry from list. 68 * @entry: the element to delete from the list. 69 * Note: list_empty on entry does not return true after this, the entry is 70 * in an undefined state. 71 */ 72 void list_del(struct list_head *entry) 73 { 74 __list_del_entry(entry); 75 entry->next = LIST_POISON1; 76 entry->prev = LIST_POISON2; 77 } 78 EXPORT_SYMBOL(list_del); 79 80 /* 81 * RCU variants. 82 */ 83 void __list_add_rcu(struct list_head *new, 84 struct list_head *prev, struct list_head *next) 85 { 86 WARN(next->prev != prev, 87 "list_add_rcu corruption. next->prev should be " 88 "prev (%p), but was %p. (next=%p).\n", 89 prev, next->prev, next); 90 WARN(prev->next != next, 91 "list_add_rcu corruption. prev->next should be " 92 "next (%p), but was %p. (prev=%p).\n", 93 next, prev->next, prev); 94 new->next = next; 95 new->prev = prev; 96 rcu_assign_pointer(list_next_rcu(prev), new); 97 next->prev = new; 98 } 99 EXPORT_SYMBOL(__list_add_rcu); 100