diff options
Diffstat (limited to 'src/helper/list.h')
| -rw-r--r-- | src/helper/list.h | 570 |
1 files changed, 433 insertions, 137 deletions
diff --git a/src/helper/list.h b/src/helper/list.h index 7f60464..a7cd4ad 100644 --- a/src/helper/list.h +++ b/src/helper/list.h @@ -1,26 +1,43 @@ +/* SPDX-License-Identifier: GPL-2.0-only */ + +/* + * The content of this file is mainly copied/inspired from Linux kernel + * code in include/linux/list.h, include/linux/types.h + * Last aligned with kernel v5.12: + * - skip the functions hlist_unhashed_lockless() and __list_del_clearprev() + * that are relevant only in kernel; + * - Remove non-standard GCC extension "omitted conditional operand" from + * list_prepare_entry; + * - expand READ_ONCE, WRITE_ONCE, smp_load_acquire, smp_store_release; + * - make comments compatible with doxygen. + * + * There is an example of using this file in contrib/list_example.c. + */ + #ifndef OPENOCD_HELPER_LIST_H #define OPENOCD_HELPER_LIST_H /* begin local changes */ #include <helper/types.h> -#define prefetch(x) ((void)x) #define LIST_POISON1 NULL #define LIST_POISON2 NULL struct list_head { struct list_head *next, *prev; }; + struct hlist_head { struct hlist_node *first; }; + struct hlist_node { struct hlist_node *next, **pprev; }; /* end local changes */ /* - * Simple doubly linked list implementation. + * Circular doubly linked list implementation. * * Some of the internal functions ("__xxx") are useful when * manipulating whole lists rather than single entries, as @@ -31,36 +48,58 @@ struct hlist_node { #define LIST_HEAD_INIT(name) { &(name), &(name) } -#define LIST_HEAD(name) \ +#define LIST_HEAD(name) \ struct list_head name = LIST_HEAD_INIT(name) +/** + * INIT_LIST_HEAD - Initialize a list_head structure + * @param list list_head structure to be initialized. + * + * Initializes the list_head to point to itself. If it is a list header, + * the result is an empty list. + */ static inline void INIT_LIST_HEAD(struct list_head *list) { list->next = list; list->prev = list; } +#ifdef CONFIG_DEBUG_LIST +extern bool __list_add_valid(struct list_head *new, + struct list_head *prev, + struct list_head *next); +extern bool __list_del_entry_valid(struct list_head *entry); +#else +static inline bool __list_add_valid(struct list_head *new, + struct list_head *prev, + struct list_head *next) +{ + return true; +} +static inline bool __list_del_entry_valid(struct list_head *entry) +{ + return true; +} +#endif + /* * Insert a new entry between two known consecutive entries. * * This is only for internal list manipulation where we know * the prev/next entries already! */ -#ifndef CONFIG_DEBUG_LIST static inline void __list_add(struct list_head *new, - struct list_head *prev, - struct list_head *next) + struct list_head *prev, + struct list_head *next) { + if (!__list_add_valid(new, prev, next)) + return; + next->prev = new; new->next = next; new->prev = prev; prev->next = new; } -#else -extern void __list_add(struct list_head *new, - struct list_head *prev, - struct list_head *next); -#endif /** * list_add - add a new entry @@ -102,28 +141,28 @@ static inline void __list_del(struct list_head *prev, struct list_head *next) prev->next = next; } +/* Ignore kernel __list_del_clearprev() */ + +static inline void __list_del_entry(struct list_head *entry) +{ + if (!__list_del_entry_valid(entry)) + return; + + __list_del(entry->prev, entry->next); +} + /** * list_del - deletes entry from list. * @param entry the element to delete from the list. * Note: list_empty() on entry does not return true after this, the entry is * in an undefined state. */ -#ifndef CONFIG_DEBUG_LIST -static inline void __list_del_entry(struct list_head *entry) -{ - __list_del(entry->prev, entry->next); -} - static inline void list_del(struct list_head *entry) { - __list_del(entry->prev, entry->next); + __list_del_entry(entry); entry->next = LIST_POISON1; entry->prev = LIST_POISON2; } -#else -extern void __list_del_entry(struct list_head *entry); -extern void list_del(struct list_head *entry); -#endif /** * list_replace - replace old entry by new one @@ -133,7 +172,7 @@ extern void list_del(struct list_head *entry); * If @a old was empty, it will be overwritten. */ static inline void list_replace(struct list_head *old, - struct list_head *new) + struct list_head *new) { new->next = old->next; new->next->prev = new; @@ -141,14 +180,38 @@ static inline void list_replace(struct list_head *old, new->prev->next = new; } +/** + * list_replace_init - replace old entry by new one and initialize the old one + * @param old the element to be replaced + * @param new the new element to insert + * + * If @a old was empty, it will be overwritten. + */ static inline void list_replace_init(struct list_head *old, - struct list_head *new) + struct list_head *new) { list_replace(old, new); INIT_LIST_HEAD(old); } /** + * list_swap - replace entry1 with entry2 and re-add entry1 at entry2's position + * @param entry1 the location to place entry2 + * @param entry2 the location to place entry1 + */ +static inline void list_swap(struct list_head *entry1, + struct list_head *entry2) +{ + struct list_head *pos = entry2->prev; + + list_del(entry2); + list_replace(entry1, entry2); + if (pos == entry1) + pos = entry2; + list_add(entry1, pos); +} + +/** * list_del_init - deletes entry from list and reinitialize it. * @param entry the element to delete from the list. */ @@ -175,19 +238,53 @@ static inline void list_move(struct list_head *list, struct list_head *head) * @param head the head that will follow our entry */ static inline void list_move_tail(struct list_head *list, - struct list_head *head) + struct list_head *head) { __list_del_entry(list); list_add_tail(list, head); } /** + * list_bulk_move_tail - move a subsection of a list to its tail + * @param head the head that will follow our entry + * @param first the first entry to move + * @param last the last entry to move, can be the same as first + * + * Move all entries between @a first and including @a last before @a head. + * All three entries must belong to the same linked list. + */ +static inline void list_bulk_move_tail(struct list_head *head, + struct list_head *first, + struct list_head *last) +{ + first->prev->next = last->next; + last->next->prev = first->prev; + + head->prev->next = first; + first->prev = head->prev; + + last->next = head; + head->prev = last; +} + +/** + * list_is_first -- tests whether @a list is the first entry in list @a head + * @param list the entry to test + * @param head the head of the list + */ +static inline int list_is_first(const struct list_head *list, + const struct list_head *head) +{ + return list->prev == head; +} + +/** * list_is_last - tests whether @a list is the last entry in list @a head * @param list the entry to test * @param head the head of the list */ static inline int list_is_last(const struct list_head *list, - const struct list_head *head) + const struct list_head *head) { return list->next == head; } @@ -202,6 +299,24 @@ static inline int list_empty(const struct list_head *head) } /** + * list_del_init_careful - deletes entry from list and reinitialize it. + * @param entry the element to delete from the list. + * + * This is the same as list_del_init(), except designed to be used + * together with list_empty_careful() in a way to guarantee ordering + * of other memory operations. + * + * Any memory operations done before a list_del_init_careful() are + * guaranteed to be visible after a list_empty_careful() test. + */ +static inline void list_del_init_careful(struct list_head *entry) +{ + __list_del_entry(entry); + entry->prev = entry; + entry->next = entry; +} + +/** * list_empty_careful - tests whether a list is empty and not being modified * @param head the list to test * @@ -235,6 +350,24 @@ static inline void list_rotate_left(struct list_head *head) } /** + * list_rotate_to_front() - Rotate list to specific item. + * @param list The desired new front of the list. + * @param head The head of the list. + * + * Rotates list so that @a list becomes the new front of the list. + */ +static inline void list_rotate_to_front(struct list_head *list, + struct list_head *head) +{ + /* + * Deletes the list head from the list denoted by @a head and + * places it as the tail of @a list, this effectively rotates the + * list so that @a list is at the front. + */ + list_move_tail(head, list); +} + +/** * list_is_singular - tests whether a list has just one entry. * @param head the list to test. */ @@ -244,7 +377,7 @@ static inline int list_is_singular(const struct list_head *head) } static inline void __list_cut_position(struct list_head *list, - struct list_head *head, struct list_head *entry) + struct list_head *head, struct list_head *entry) { struct list_head *new_first = entry->next; list->next = head->next; @@ -270,12 +403,12 @@ static inline void __list_cut_position(struct list_head *list, * */ static inline void list_cut_position(struct list_head *list, - struct list_head *head, struct list_head *entry) + struct list_head *head, struct list_head *entry) { if (list_empty(head)) return; if (list_is_singular(head) && - (head->next != entry && head != entry)) + (head->next != entry && head != entry)) return; if (entry == head) INIT_LIST_HEAD(list); @@ -283,9 +416,39 @@ static inline void list_cut_position(struct list_head *list, __list_cut_position(list, head, entry); } +/** + * list_cut_before - cut a list into two, before given entry + * @param list a new list to add all removed entries + * @param head a list with entries + * @param entry an entry within head, could be the head itself + * + * This helper moves the initial part of @a head, up to but + * excluding @a entry, from @a head to @a list. You should pass + * in @a entry an element you know is on @a head. @a list should + * be an empty list or a list you do not care about losing + * its data. + * If @a entry == @a head, all entries on @a head are moved to + * @a list. + */ +static inline void list_cut_before(struct list_head *list, + struct list_head *head, + struct list_head *entry) +{ + if (head->next == entry) { + INIT_LIST_HEAD(list); + return; + } + list->next = head->next; + list->next->prev = list; + list->prev = entry->prev; + list->prev->next = list; + head->next = entry; + entry->prev = head; +} + static inline void __list_splice(const struct list_head *list, - struct list_head *prev, - struct list_head *next) + struct list_head *prev, + struct list_head *next) { struct list_head *first = list->next; struct list_head *last = list->prev; @@ -303,7 +466,7 @@ static inline void __list_splice(const struct list_head *list, * @param head the place to add it in the first list. */ static inline void list_splice(const struct list_head *list, - struct list_head *head) + struct list_head *head) { if (!list_empty(list)) __list_splice(list, head, head->next); @@ -315,7 +478,7 @@ static inline void list_splice(const struct list_head *list, * @param head the place to add it in the first list. */ static inline void list_splice_tail(struct list_head *list, - struct list_head *head) + struct list_head *head) { if (!list_empty(list)) __list_splice(list, head->prev, head); @@ -329,7 +492,7 @@ static inline void list_splice_tail(struct list_head *list, * The list at @a list is reinitialised */ static inline void list_splice_init(struct list_head *list, - struct list_head *head) + struct list_head *head) { if (!list_empty(list)) { __list_splice(list, head, head->next); @@ -346,7 +509,7 @@ static inline void list_splice_init(struct list_head *list, * The list at @a list is reinitialised */ static inline void list_splice_tail_init(struct list_head *list, - struct list_head *head) + struct list_head *head) { if (!list_empty(list)) { __list_splice(list, head->prev, head); @@ -358,7 +521,7 @@ static inline void list_splice_tail_init(struct list_head *list, * list_entry - get the struct for this entry * @param ptr the &struct list_head pointer. * @param type the type of the struct this is embedded in. - * @param member the name of the list_struct within the struct. + * @param member the name of the list_head within the struct. */ #define list_entry(ptr, type, member) \ container_of(ptr, type, member) @@ -367,7 +530,7 @@ static inline void list_splice_tail_init(struct list_head *list, * list_first_entry - get the first element from a list * @param ptr the list head to take the element from. * @param type the type of the struct this is embedded in. - * @param member the name of the list_struct within the struct. + * @param member the name of the list_head within the struct. * * Note, that list is expected to be not empty. */ @@ -375,26 +538,63 @@ static inline void list_splice_tail_init(struct list_head *list, list_entry((ptr)->next, type, member) /** + * list_last_entry - get the last element from a list + * @param ptr the list head to take the element from. + * @param type the type of the struct this is embedded in. + * @param member the name of the list_head within the struct. + * + * Note, that list is expected to be not empty. + */ +#define list_last_entry(ptr, type, member) \ + list_entry((ptr)->prev, type, member) + +/** + * list_first_entry_or_null - get the first element from a list + * @param ptr the list head to take the element from. + * @param type the type of the struct this is embedded in. + * @param member the name of the list_head within the struct. + * + * Note that if the list is empty, it returns NULL. + */ +#define list_first_entry_or_null(ptr, type, member) ({ \ + struct list_head *head__ = (ptr); \ + struct list_head *pos__ = head__->next; \ + pos__ != head__ ? list_entry(pos__, type, member) : NULL; \ +}) + +/** + * list_next_entry - get the next element in list + * @param pos the type * to cursor + * @param member the name of the list_head within the struct. + */ +#define list_next_entry(pos, member) \ + list_entry((pos)->member.next, typeof(*(pos)), member) + +/** + * list_prev_entry - get the prev element in list + * @param pos the type * to cursor + * @param member the name of the list_head within the struct. + */ +#define list_prev_entry(pos, member) \ + list_entry((pos)->member.prev, typeof(*(pos)), member) + +/** * list_for_each - iterate over a list * @param pos the &struct list_head to use as a loop cursor. * @param head the head for your list. */ #define list_for_each(pos, head) \ - for (pos = (head)->next; prefetch(pos->next), pos != (head); \ - pos = pos->next) + for (pos = (head)->next; pos != (head); pos = pos->next) /** - * __list_for_each - iterate over a list + * list_for_each_continue - continue iteration over a list * @param pos the &struct list_head to use as a loop cursor. * @param head the head for your list. * - * This variant differs from list_for_each() in that it's the - * simplest possible list iteration code, no prefetching is done. - * Use this for code that knows the list to be very short (empty - * or 1 entry) most of the time. + * Continue to iterate over a list, continuing after the current position. */ -#define __list_for_each(pos, head) \ - for (pos = (head)->next; pos != (head); pos = pos->next) +#define list_for_each_continue(pos, head) \ + for (pos = pos->next; pos != (head); pos = pos->next) /** * list_for_each_prev - iterate over a list backwards @@ -402,8 +602,7 @@ static inline void list_splice_tail_init(struct list_head *list, * @param head the head for your list. */ #define list_for_each_prev(pos, head) \ - for (pos = (head)->prev; prefetch(pos->prev), pos != (head); \ - pos = pos->prev) + for (pos = (head)->prev; pos != (head); pos = pos->prev) /** * list_for_each_safe - iterate over a list safe against removal of list entry @@ -413,7 +612,7 @@ static inline void list_splice_tail_init(struct list_head *list, */ #define list_for_each_safe(pos, n, head) \ for (pos = (head)->next, n = pos->next; pos != (head); \ - pos = n, n = pos->next) + pos = n, n = pos->next) /** * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry @@ -422,148 +621,170 @@ static inline void list_splice_tail_init(struct list_head *list, * @param head the head for your list. */ #define list_for_each_prev_safe(pos, n, head) \ - for (pos = (head)->prev, n = pos->prev; \ - prefetch(pos->prev), pos != (head); \ + for (pos = (head)->prev, n = pos->prev; \ + pos != (head); \ pos = n, n = pos->prev) /** + * list_entry_is_head - test if the entry points to the head of the list + * @param pos the type * to cursor + * @param head the head for your list. + * @param member the name of the list_head within the struct. + */ +#define list_entry_is_head(pos, head, member) \ + (&pos->member == (head)) + +/** * list_for_each_entry - iterate over list of given type * @param pos the type * to use as a loop cursor. * @param head the head for your list. - * @param member the name of the list_struct within the struct. + * @param member the name of the list_head within the struct. */ #define list_for_each_entry(pos, head, member) \ - for (pos = list_entry((head)->next, typeof(*pos), member); \ - prefetch(pos->member.next), &pos->member != (head); \ - pos = list_entry(pos->member.next, typeof(*pos), member)) + for (pos = list_first_entry(head, typeof(*pos), member); \ + !list_entry_is_head(pos, head, member); \ + pos = list_next_entry(pos, member)) /** * list_for_each_entry_reverse - iterate backwards over list of given type. * @param pos the type * to use as a loop cursor. * @param head the head for your list. - * @param member the name of the list_struct within the struct. + * @param member the name of the list_head within the struct. */ #define list_for_each_entry_reverse(pos, head, member) \ - for (pos = list_entry((head)->prev, typeof(*pos), member); \ - prefetch(pos->member.prev), &pos->member != (head); \ - pos = list_entry(pos->member.prev, typeof(*pos), member)) + for (pos = list_last_entry(head, typeof(*pos), member); \ + !list_entry_is_head(pos, head, member); \ + pos = list_prev_entry(pos, member)) /** * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue() * @param pos the type * to use as a start point * @param head the head of the list - * @param member the name of the list_struct within the struct. + * @param member the name of the list_head 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)) + ((pos) ? (pos) : list_entry(head, typeof(*pos), member)) /** * list_for_each_entry_continue - continue iteration over list of given type * @param pos the type * to use as a loop cursor. * @param head the head for your list. - * @param member the name of the list_struct within the struct. + * @param member the name of the list_head 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); \ - prefetch(pos->member.next), &pos->member != (head); \ - pos = list_entry(pos->member.next, typeof(*pos), member)) +#define list_for_each_entry_continue(pos, head, member) \ + for (pos = list_next_entry(pos, member); \ + !list_entry_is_head(pos, head, member); \ + pos = list_next_entry(pos, member)) /** * list_for_each_entry_continue_reverse - iterate backwards from the given point * @param pos the type * to use as a loop cursor. * @param head the head for your list. - * @param member the name of the list_struct within the struct. + * @param member the name of the list_head within the struct. * * Start to iterate over list of given type backwards, continuing after * the current position. */ #define list_for_each_entry_continue_reverse(pos, head, member) \ - for (pos = list_entry(pos->member.prev, typeof(*pos), member); \ - prefetch(pos->member.prev), &pos->member != (head); \ - pos = list_entry(pos->member.prev, typeof(*pos), member)) + for (pos = list_prev_entry(pos, member); \ + !list_entry_is_head(pos, head, member); \ + pos = list_prev_entry(pos, member)) /** * list_for_each_entry_from - iterate over list of given type from the current point * @param pos the type * to use as a loop cursor. * @param head the head for your list. - * @param member the name of the list_struct within the struct. + * @param member the name of the list_head 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); \ - pos = list_entry(pos->member.next, typeof(*pos), member)) + for (; !list_entry_is_head(pos, head, member); \ + pos = list_next_entry(pos, member)) + +/** + * list_for_each_entry_from_reverse - iterate backwards over list of given type + * from the current point + * @param pos the type * to use as a loop cursor. + * @param head the head for your list. + * @param member the name of the list_head within the struct. + * + * Iterate backwards over list of given type, continuing from current position. + */ +#define list_for_each_entry_from_reverse(pos, head, member) \ + for (; !list_entry_is_head(pos, head, member); \ + pos = list_prev_entry(pos, member)) /** * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry * @param pos the type * to use as a loop cursor. * @param n another type * to use as temporary storage * @param head the head for your list. - * @param member the name of the list_struct within the struct. + * @param member the name of the list_head within the struct. */ #define list_for_each_entry_safe(pos, n, head, member) \ - for (pos = list_entry((head)->next, typeof(*pos), member), \ - n = list_entry(pos->member.next, typeof(*pos), member); \ - &pos->member != (head); \ - pos = n, n = list_entry(n->member.next, typeof(*n), member)) + for (pos = list_first_entry(head, typeof(*pos), member), \ + n = list_next_entry(pos, member); \ + !list_entry_is_head(pos, head, member); \ + pos = n, n = list_next_entry(n, member)) /** * list_for_each_entry_safe_continue - continue list iteration safe against removal * @param pos the type * to use as a loop cursor. * @param n another type * to use as temporary storage * @param head the head for your list. - * @param member the name of the list_struct within the struct. + * @param member the name of the list_head 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), \ - n = list_entry(pos->member.next, typeof(*pos), member); \ - &pos->member != (head); \ - pos = n, n = list_entry(n->member.next, typeof(*n), member)) +#define list_for_each_entry_safe_continue(pos, n, head, member) \ + for (pos = list_next_entry(pos, member), \ + n = list_next_entry(pos, member); \ + !list_entry_is_head(pos, head, member); \ + pos = n, n = list_next_entry(n, member)) /** * list_for_each_entry_safe_from - iterate over list from current point safe against removal * @param pos the type * to use as a loop cursor. * @param n another type * to use as temporary storage * @param head the head for your list. - * @param member the name of the list_struct within the struct. + * @param member the name of the list_head 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); \ - &pos->member != (head); \ - pos = n, n = list_entry(n->member.next, typeof(*n), member)) + for (n = list_next_entry(pos, member); \ + !list_entry_is_head(pos, head, member); \ + pos = n, n = list_next_entry(n, member)) /** * list_for_each_entry_safe_reverse - iterate backwards over list safe against removal * @param pos the type * to use as a loop cursor. * @param n another type * to use as temporary storage * @param head the head for your list. - * @param member the name of the list_struct within the struct. + * @param member the name of the list_head 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), \ - n = list_entry(pos->member.prev, typeof(*pos), member); \ - &pos->member != (head); \ - pos = n, n = list_entry(n->member.prev, typeof(*n), member)) + for (pos = list_last_entry(head, typeof(*pos), member), \ + n = list_prev_entry(pos, member); \ + !list_entry_is_head(pos, head, member); \ + pos = n, n = list_prev_entry(n, member)) /** * list_safe_reset_next - reset a stale list_for_each_entry_safe loop * @param pos the loop cursor used in the list_for_each_entry_safe loop * @param n temporary storage used in list_for_each_entry_safe - * @param member the name of the list_struct within the struct. + * @param member the name of the list_head within the struct. * * list_safe_reset_next is not safe to use in general if the list may be * modified concurrently (eg. the lock is dropped in the loop body). An @@ -572,7 +793,7 @@ static inline void list_splice_tail_init(struct list_head *list, * completing the current iteration of the loop body. */ #define list_safe_reset_next(pos, n, member) \ - n = list_entry(pos->member.next, typeof(*pos), member) + n = list_next_entry(pos, member) /* * Double linked lists with a single pointer list head. @@ -590,11 +811,25 @@ static inline void INIT_HLIST_NODE(struct hlist_node *h) h->pprev = NULL; } +/** + * hlist_unhashed - Has node been removed from list and reinitialized? + * @param h Node to be checked + * + * Not that not all removal functions will leave a node in unhashed + * state. For example, hlist_nulls_del_init_rcu() does leave the + * node in unhashed state, but hlist_nulls_del() does not. + */ static inline int hlist_unhashed(const struct hlist_node *h) { return !h->pprev; } +/* Ignore kernel hlist_unhashed_lockless() */ + +/** + * hlist_empty - Is the specified hlist_head structure an empty hlist? + * @param h Structure to check. + */ static inline int hlist_empty(const struct hlist_head *h) { return !h->first; @@ -604,11 +839,19 @@ static inline void __hlist_del(struct hlist_node *n) { struct hlist_node *next = n->next; struct hlist_node **pprev = n->pprev; + *pprev = next; if (next) next->pprev = pprev; } +/** + * hlist_del - Delete the specified hlist_node from its list + * @param n Node to delete. + * + * Note that this function leaves the node in hashed state. Use + * hlist_del_init() or similar instead to unhash @a n. + */ static inline void hlist_del(struct hlist_node *n) { __hlist_del(n); @@ -616,6 +859,12 @@ static inline void hlist_del(struct hlist_node *n) n->pprev = LIST_POISON2; } +/** + * hlist_del_init - Delete the specified hlist_node from its list and initialize + * @param n Node to delete. + * + * Note that this function leaves the node in unhashed state. + */ static inline void hlist_del_init(struct hlist_node *n) { if (!hlist_unhashed(n)) { @@ -624,6 +873,14 @@ static inline void hlist_del_init(struct hlist_node *n) } } +/** + * hlist_add_head - add a new entry at the beginning of the hlist + * @param n new entry to be added + * @param h hlist head to add it after + * + * Insert a new entry after the specified head. + * This is good for implementing stacks. + */ static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h) { struct hlist_node *first = h->first; @@ -634,9 +891,13 @@ static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h) n->pprev = &h->first; } -/* next must be != NULL */ +/** + * hlist_add_before - add a new entry before the one specified + * @param n new entry to be added + * @param next hlist node to add it before, which must be non-NULL + */ static inline void hlist_add_before(struct hlist_node *n, - struct hlist_node *next) + struct hlist_node *next) { n->pprev = next->pprev; n->next = next; @@ -644,29 +905,68 @@ static inline void hlist_add_before(struct hlist_node *n, *(n->pprev) = n; } -static inline void hlist_add_after(struct hlist_node *n, - struct hlist_node *next) +/** + * hlist_add_behind - add a new entry after the one specified + * @param n new entry to be added + * @param prev hlist node to add it after, which must be non-NULL + */ +static inline void hlist_add_behind(struct hlist_node *n, + struct hlist_node *prev) { - next->next = n->next; - n->next = next; - next->pprev = &n->next; + n->next = prev->next; + prev->next = n; + n->pprev = &prev->next; - if (next->next) - next->next->pprev = &next->next; + if (n->next) + n->next->pprev = &n->next; } -/* after that we'll appear to be on some hlist and hlist_del will work */ +/** + * hlist_add_fake - create a fake hlist consisting of a single headless node + * @param n Node to make a fake list out of + * + * This makes @a n appear to be its own predecessor on a headless hlist. + * The point of this is to allow things like hlist_del() to work correctly + * in cases where there is no list. + */ static inline void hlist_add_fake(struct hlist_node *n) { n->pprev = &n->next; } -/* +/** + * hlist_fake: Is this node a fake hlist? + * @param h Node to check for being a self-referential fake hlist. + */ +static inline bool hlist_fake(struct hlist_node *h) +{ + return h->pprev == &h->next; +} + +/** + * hlist_is_singular_node - is node the only element of the specified hlist? + * @param n Node to check for singularity. + * @param h Header for potentially singular list. + * + * Check whether the node is the only node of the head without + * accessing head, thus avoiding unnecessary cache misses. + */ +static inline bool +hlist_is_singular_node(struct hlist_node *n, struct hlist_head *h) +{ + return !n->next && n->pprev == &h->first; +} + +/** + * hlist_move_list - Move an hlist + * @param old hlist_head for old list. + * @param new hlist_head for new list. + * * Move a list from one list head to another. Fixup the pprev * reference of the first entry if it exists. */ static inline void hlist_move_list(struct hlist_head *old, - struct hlist_head *new) + struct hlist_head *new) { new->first = old->first; if (new->first) @@ -677,61 +977,57 @@ static inline void hlist_move_list(struct hlist_head *old, #define hlist_entry(ptr, type, member) container_of(ptr, type, member) #define hlist_for_each(pos, head) \ - for (pos = (head)->first; pos && ({ prefetch(pos->next); 1; }); \ - pos = pos->next) + for (pos = (head)->first; pos ; pos = pos->next) #define hlist_for_each_safe(pos, n, head) \ for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \ pos = n) +#define hlist_entry_safe(ptr, type, member) \ + ({ typeof(ptr) ____ptr = (ptr); \ + ____ptr ? hlist_entry(____ptr, type, member) : NULL; \ + }) + /** * hlist_for_each_entry - iterate over list of given type - * @param tpos the type * to use as a loop cursor. - * @param pos the &struct hlist_node to use as a loop cursor. + * @param pos the type * to use as a loop cursor. * @param head the head for your list. * @param member the name of the hlist_node within the struct. */ -#define hlist_for_each_entry(tpos, pos, head, member) \ - for (pos = (head)->first; \ - pos && ({ prefetch(pos->next); 1; }) && \ - ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1; }); \ - pos = pos->next) +#define hlist_for_each_entry(pos, head, member) \ + for (pos = hlist_entry_safe((head)->first, typeof(*(pos)), member);\ + pos; \ + pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member)) /** * hlist_for_each_entry_continue - iterate over a hlist continuing after current point - * @param tpos the type * to use as a loop cursor. - * @param pos the &struct hlist_node to use as a loop cursor. + * @param pos the type * to use as a loop cursor. * @param member the name of the hlist_node within the struct. */ -#define hlist_for_each_entry_continue(tpos, pos, member) \ - for (pos = (pos)->next; \ - pos && ({ prefetch(pos->next); 1; }) && \ - ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1; }); \ - pos = pos->next) +#define hlist_for_each_entry_continue(pos, member) \ + for (pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member);\ + pos; \ + pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member)) /** * hlist_for_each_entry_from - iterate over a hlist continuing from current point - * @param tpos the type * to use as a loop cursor. - * @param pos the &struct hlist_node to use as a loop cursor. + * @param pos the type * to use as a loop cursor. * @param member the name of the hlist_node within the struct. */ -#define hlist_for_each_entry_from(tpos, pos, member) \ - for (; pos && ({ prefetch(pos->next); 1; }) && \ - ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1; }); \ - pos = pos->next) +#define hlist_for_each_entry_from(pos, member) \ + for (; pos; \ + pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member)) /** * hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry - * @param tpos the type * to use as a loop cursor. - * @param pos the &struct hlist_node to use as a loop cursor. - * @param n another &struct hlist_node to use as temporary storage + * @param pos the type * to use as a loop cursor. + * @param n a &struct hlist_node to use as temporary storage * @param head the head for your list. * @param member the name of the hlist_node within the struct. */ -#define hlist_for_each_entry_safe(tpos, pos, n, head, member) \ - for (pos = (head)->first; \ - pos && ({ n = pos->next; 1; }) && \ - ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1; }); \ - pos = n) +#define hlist_for_each_entry_safe(pos, n, head, member) \ + for (pos = hlist_entry_safe((head)->first, typeof(*pos), member);\ + pos && ({ n = pos->member.next; 1; }); \ + pos = hlist_entry_safe(n, typeof(*pos), member)) #endif /* OPENOCD_HELPER_LIST_H */ |