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/module.h> 10 #include <linux/list.h> 11 12 /* 13 * Insert a new entry between two known consecutive entries. 14 * 15 * This is only for internal list manipulation where we know 16 * the prev/next entries already! 17 */ 18 19 void __list_add(struct list_head *new, 20 struct list_head *prev, 21 struct list_head *next) 22 { 23 if (unlikely(next->prev != prev)) { 24 printk(KERN_ERR "list_add corruption. next->prev should be " 25 "prev (%p), but was %p. (next=%p).\n", 26 prev, next->prev, next); 27 BUG(); 28 } 29 if (unlikely(prev->next != next)) { 30 printk(KERN_ERR "list_add corruption. prev->next should be " 31 "next (%p), but was %p. (prev=%p).\n", 32 next, prev->next, prev); 33 BUG(); 34 } 35 next->prev = new; 36 new->next = next; 37 new->prev = prev; 38 prev->next = new; 39 } 40 EXPORT_SYMBOL(__list_add); 41 42 /** 43 * list_add - add a new entry 44 * @new: new entry to be added 45 * @head: list head to add it after 46 * 47 * Insert a new entry after the specified head. 48 * This is good for implementing stacks. 49 */ 50 void list_add(struct list_head *new, struct list_head *head) 51 { 52 __list_add(new, head, head->next); 53 } 54 EXPORT_SYMBOL(list_add); 55 56 /** 57 * list_del - deletes entry from list. 58 * @entry: the element to delete from the list. 59 * Note: list_empty on entry does not return true after this, the entry is 60 * in an undefined state. 61 */ 62 void list_del(struct list_head *entry) 63 { 64 if (unlikely(entry->prev->next != entry)) { 65 printk(KERN_ERR "list_del corruption. prev->next should be %p, " 66 "but was %p\n", entry, entry->prev->next); 67 BUG(); 68 } 69 if (unlikely(entry->next->prev != entry)) { 70 printk(KERN_ERR "list_del corruption. next->prev should be %p, " 71 "but was %p\n", entry, entry->next->prev); 72 BUG(); 73 } 74 __list_del(entry->prev, entry->next); 75 entry->next = LIST_POISON1; 76 entry->prev = LIST_POISON2; 77 } 78 EXPORT_SYMBOL(list_del); 79