diff options
Diffstat (limited to '')
| -rw-r--r-- | include/linux/list.h | 166 |
1 files changed, 102 insertions, 64 deletions
diff --git a/include/linux/list.h b/include/linux/list.h index 76f05718342c..6b74adf5297f 100644 --- a/include/linux/list.h +++ b/include/linux/list.h @@ -4,18 +4,11 @@ #ifdef __KERNEL__ #include <linux/stddef.h> +#include <linux/poison.h> #include <linux/prefetch.h> #include <asm/system.h> /* - * These are non-NULL pointers that will result in page faults - * under normal circumstances, used to verify that nobody uses - * non-initialized list entries. - */ -#define LIST_POISON1 ((void *) 0x00100100) -#define LIST_POISON2 ((void *) 0x00200200) - -/* * Simple doubly linked list implementation. * * Some of the internal functions ("__xxx") are useful when @@ -197,12 +190,35 @@ static inline void list_del_rcu(struct list_head *entry) entry->prev = LIST_POISON2; } +/** + * list_replace - replace old entry by new one + * @old : the element to be replaced + * @new : the new element to insert + * Note: if 'old' was empty, it will be overwritten. + */ +static inline void list_replace(struct list_head *old, + struct list_head *new) +{ + new->next = old->next; + new->next->prev = new; + new->prev = old->prev; + new->prev->next = new; +} + +static inline void list_replace_init(struct list_head *old, + struct list_head *new) +{ + list_replace(old, new); + INIT_LIST_HEAD(old); +} + /* * list_replace_rcu - replace old entry by new one * @old : the element to be replaced * @new : the new element to insert * * The old entry will be replaced with the new entry atomically. + * Note: 'old' should not be empty. */ static inline void list_replace_rcu(struct list_head *old, struct list_head *new) @@ -258,16 +274,17 @@ static inline int list_empty(const struct list_head *head) } /** - * list_empty_careful - tests whether a list is - * empty _and_ checks that no other CPU might be - * in the process of still modifying either member + * list_empty_careful - tests whether a list is empty and not being modified + * @head: the list to test + * + * Description: + * tests whether a list is empty _and_ checks that no other CPU might be + * in the process of modifying either member (next or prev) * * NOTE: using list_empty_careful() without synchronization * can only be safe if the only activity that can happen * to the list entry is list_del_init(). Eg. it cannot be used * if another CPU could re-list_add() it. - * - * @head: the list to test. */ static inline int list_empty_careful(const struct list_head *head) { @@ -327,7 +344,7 @@ static inline void list_splice_init(struct list_head *list, /** * list_for_each - iterate over a list - * @pos: the &struct list_head to use as a loop counter. + * @pos: the &struct list_head to use as a loop cursor. * @head: the head for your list. */ #define list_for_each(pos, head) \ @@ -336,7 +353,7 @@ static inline void list_splice_init(struct list_head *list, /** * __list_for_each - iterate over a list - * @pos: the &struct list_head to use as a loop counter. + * @pos: the &struct list_head to use as a loop cursor. * @head: the head for your list. * * This variant differs from list_for_each() in that it's the @@ -349,7 +366,7 @@ static inline void list_splice_init(struct list_head *list, /** * list_for_each_prev - iterate over a list backwards - * @pos: the &struct list_head to use as a loop counter. + * @pos: the &struct list_head to use as a loop cursor. * @head: the head for your list. */ #define list_for_each_prev(pos, head) \ @@ -357,8 +374,8 @@ static inline void list_splice_init(struct list_head *list, pos = pos->prev) /** - * list_for_each_safe - iterate over a list safe against removal of list entry - * @pos: the &struct list_head to use as a loop counter. + * list_for_each_safe - iterate over a list safe against removal of list entry + * @pos: the &struct list_head to use as a loop cursor. * @n: another &struct list_head to use as temporary storage * @head: the head for your list. */ @@ -368,7 +385,7 @@ static inline void list_splice_init(struct list_head *list, /** * list_for_each_entry - iterate over list of given type - * @pos: the type * to use as a loop counter. + * @pos: the type * to use as a loop cursor. * @head: the head for your list. * @member: the name of the list_struct within the struct. */ @@ -379,7 +396,7 @@ static inline void list_splice_init(struct list_head *list, /** * list_for_each_entry_reverse - iterate backwards over list of given type. - * @pos: the type * to use as a loop counter. + * @pos: the type * to use as a loop cursor. * @head: the head for your list. * @member: the name of the list_struct within the struct. */ @@ -389,21 +406,24 @@ static inline void list_splice_init(struct list_head *list, pos = list_entry(pos->member.prev, typeof(*pos), member)) /** - * list_prepare_entry - prepare a pos entry for use as a start point in - * list_for_each_entry_continue + * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue * @pos: the type * to use as a start point * @head: the head of the list * @member: the name of the list_struct within the struct. + * + * Prepares a pos entry for use as a start point in list_for_each_entry_continue. */ #define list_prepare_entry(pos, head, member) \ ((pos) ? : list_entry(head, typeof(*pos), member)) /** - * list_for_each_entry_continue - iterate over list of given type - * continuing after existing point - * @pos: the type * to use as a loop counter. + * list_for_each_entry_continue - continue iteration over list of given type + * @pos: the type * to use as a loop cursor. * @head: the head for your list. * @member: the name of the list_struct within the struct. + * + * Continue to iterate over list of given type, continuing after + * the current position. */ #define list_for_each_entry_continue(pos, head, member) \ for (pos = list_entry(pos->member.next, typeof(*pos), member); \ @@ -411,11 +431,12 @@ static inline void list_splice_init(struct list_head *list, pos = list_entry(pos->member.next, typeof(*pos), member)) /** - * list_for_each_entry_from - iterate over list of given type - * continuing from existing point - * @pos: the type * to use as a loop counter. + * list_for_each_entry_from - iterate over list of given type from the current point + * @pos: the type * to use as a loop cursor. * @head: the head for your list. * @member: the name of the list_struct within the struct. + * + * Iterate over list of given type, continuing from current position. */ #define list_for_each_entry_from(pos, head, member) \ for (; prefetch(pos->member.next), &pos->member != (head); \ @@ -423,7 +444,7 @@ static inline void list_splice_init(struct list_head *list, /** * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry - * @pos: the type * to use as a loop counter. + * @pos: the type * to use as a loop cursor. * @n: another type * to use as temporary storage * @head: the head for your list. * @member: the name of the list_struct within the struct. @@ -435,12 +456,14 @@ static inline void list_splice_init(struct list_head *list, pos = n, n = list_entry(n->member.next, typeof(*n), member)) /** - * list_for_each_entry_safe_continue - iterate over list of given type - * continuing after existing point safe against removal of list entry - * @pos: the type * to use as a loop counter. + * list_for_each_entry_safe_continue + * @pos: the type * to use as a loop cursor. * @n: another type * to use as temporary storage * @head: the head for your list. * @member: the name of the list_struct within the struct. + * + * Iterate over list of given type, continuing after current point, + * safe against removal of list entry. */ #define list_for_each_entry_safe_continue(pos, n, head, member) \ for (pos = list_entry(pos->member.next, typeof(*pos), member), \ @@ -449,12 +472,14 @@ static inline void list_splice_init(struct list_head *list, pos = n, n = list_entry(n->member.next, typeof(*n), member)) /** - * list_for_each_entry_safe_from - iterate over list of given type - * from existing point safe against removal of list entry - * @pos: the type * to use as a loop counter. + * list_for_each_entry_safe_from + * @pos: the type * to use as a loop cursor. * @n: another type * to use as temporary storage * @head: the head for your list. * @member: the name of the list_struct within the struct. + * + * Iterate over list of given type from current point, safe against + * removal of list entry. */ #define list_for_each_entry_safe_from(pos, n, head, member) \ for (n = list_entry(pos->member.next, typeof(*pos), member); \ @@ -462,12 +487,14 @@ static inline void list_splice_init(struct list_head *list, pos = n, n = list_entry(n->member.next, typeof(*n), member)) /** - * list_for_each_entry_safe_reverse - iterate backwards over list of given type safe against - * removal of list entry - * @pos: the type * to use as a loop counter. + * list_for_each_entry_safe_reverse + * @pos: the type * to use as a loop cursor. * @n: another type * to use as temporary storage * @head: the head for your list. * @member: the name of the list_struct within the struct. + * + * Iterate backwards over list of given type, safe against removal + * of list entry. */ #define list_for_each_entry_safe_reverse(pos, n, head, member) \ for (pos = list_entry((head)->prev, typeof(*pos), member), \ @@ -477,7 +504,7 @@ static inline void list_splice_init(struct list_head *list, /** * list_for_each_rcu - iterate over an rcu-protected list - * @pos: the &struct list_head to use as a loop counter. + * @pos: the &struct list_head to use as a loop cursor. * @head: the head for your list. * * This list-traversal primitive may safely run concurrently with @@ -495,12 +522,13 @@ static inline void list_splice_init(struct list_head *list, pos = pos->next) /** - * list_for_each_safe_rcu - iterate over an rcu-protected list safe - * against removal of list entry - * @pos: the &struct list_head to use as a loop counter. + * list_for_each_safe_rcu + * @pos: the &struct list_head to use as a loop cursor. * @n: another &struct list_head to use as temporary storage * @head: the head for your list. * + * Iterate over an rcu-protected list, safe against removal of list entry. + * * This list-traversal primitive may safely run concurrently with * the _rcu list-mutation primitives such as list_add_rcu() * as long as the traversal is guarded by rcu_read_lock(). @@ -512,7 +540,7 @@ static inline void list_splice_init(struct list_head *list, /** * list_for_each_entry_rcu - iterate over rcu list of given type - * @pos: the type * to use as a loop counter. + * @pos: the type * to use as a loop cursor. * @head: the head for your list. * @member: the name of the list_struct within the struct. * @@ -528,11 +556,12 @@ static inline void list_splice_init(struct list_head *list, /** - * list_for_each_continue_rcu - iterate over an rcu-protected list - * continuing after existing point. - * @pos: the &struct list_head to use as a loop counter. + * list_for_each_continue_rcu + * @pos: the &struct list_head to use as a loop cursor. * @head: the head for your list. * + * Iterate over an rcu-protected list, continuing after current point. + * * This list-traversal primitive may safely run concurrently with * the _rcu list-mutation primitives such as list_add_rcu() * as long as the traversal is guarded by rcu_read_lock(). @@ -658,11 +687,14 @@ static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h) /** - * hlist_add_head_rcu - adds the specified element to the specified hlist, - * while permitting racing traversals. + * hlist_add_head_rcu * @n: the element to add to the hash list. * @h: the list to add to. * + * Description: + * Adds the specified element to the specified hlist, + * while permitting racing traversals. + * * The caller must take whatever precautions are necessary * (such as holding appropriate locks) to avoid racing * with another list-mutation primitive, such as hlist_add_head_rcu() @@ -707,11 +739,14 @@ static inline void hlist_add_after(struct hlist_node *n, } /** - * hlist_add_before_rcu - adds the specified element to the specified hlist - * before the specified node while permitting racing traversals. + * hlist_add_before_rcu * @n: the new element to add to the hash list. * @next: the existing element to add the new element before. * + * Description: + * Adds the specified element to the specified hlist + * before the specified node while permitting racing traversals. + * * The caller must take whatever precautions are necessary * (such as holding appropriate locks) to avoid racing * with another list-mutation primitive, such as hlist_add_head_rcu() @@ -732,11 +767,14 @@ static inline void hlist_add_before_rcu(struct hlist_node *n, } /** - * hlist_add_after_rcu - adds the specified element to the specified hlist - * after the specified node while permitting racing traversals. + * hlist_add_after_rcu * @prev: the existing element to add the new element after. * @n: the new element to add to the hash list. * + * Description: + * Adds the specified element to the specified hlist + * after the specified node while permitting racing traversals. + * * The caller must take whatever precautions are necessary * (such as holding appropriate locks) to avoid racing * with another list-mutation primitive, such as hlist_add_head_rcu() @@ -769,8 +807,8 @@ static inline void hlist_add_after_rcu(struct hlist_node *prev, /** * hlist_for_each_entry - iterate over list of given type - * @tpos: the type * to use as a loop counter. - * @pos: the &struct hlist_node to use as a loop counter. + * @tpos: the type * to use as a loop cursor. + * @pos: the &struct hlist_node to use as a loop cursor. * @head: the head for your list. * @member: the name of the hlist_node within the struct. */ @@ -781,9 +819,9 @@ static inline void hlist_add_after_rcu(struct hlist_node *prev, pos = pos->next) /** - * hlist_for_each_entry_continue - iterate over a hlist continuing after existing point - * @tpos: the type * to use as a loop counter. - * @pos: the &struct hlist_node to use as a loop counter. + * hlist_for_each_entry_continue - iterate over a hlist continuing after current point + * @tpos: the type * to use as a loop cursor. + * @pos: the &struct hlist_node to use as a loop cursor. * @member: the name of the hlist_node within the struct. */ #define hlist_for_each_entry_continue(tpos, pos, member) \ @@ -793,9 +831,9 @@ static inline void hlist_add_after_rcu(struct hlist_node *prev, pos = pos->next) /** - * hlist_for_each_entry_from - iterate over a hlist continuing from existing point - * @tpos: the type * to use as a loop counter. - * @pos: the &struct hlist_node to use as a loop counter. + * hlist_for_each_entry_from - iterate over a hlist continuing from current point + * @tpos: the type * to use as a loop cursor. + * @pos: the &struct hlist_node to use as a loop cursor. * @member: the name of the hlist_node within the struct. */ #define hlist_for_each_entry_from(tpos, pos, member) \ @@ -805,8 +843,8 @@ static inline void hlist_add_after_rcu(struct hlist_node *prev, /** * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry - * @tpos: the type * to use as a loop counter. - * @pos: the &struct hlist_node to use as a loop counter. + * @tpos: the type * to use as a loop cursor. + * @pos: the &struct hlist_node to use as a loop cursor. * @n: another &struct hlist_node to use as temporary storage * @head: the head for your list. * @member: the name of the hlist_node within the struct. @@ -819,8 +857,8 @@ static inline void hlist_add_after_rcu(struct hlist_node *prev, /** * hlist_for_each_entry_rcu - iterate over rcu list of given type - * @tpos: the type * to use as a loop counter. - * @pos: the &struct hlist_node to use as a loop counter. + * @tpos: the type * to use as a loop cursor. + * @pos: the &struct hlist_node to use as a loop cursor. * @head: the head for your list. * @member: the name of the hlist_node within the struct. * |