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Diffstat (limited to 'lib/decoding/osmocom/core/linuxlist.h')
| -rw-r--r-- | lib/decoding/osmocom/core/linuxlist.h | 409 |
1 files changed, 409 insertions, 0 deletions
diff --git a/lib/decoding/osmocom/core/linuxlist.h b/lib/decoding/osmocom/core/linuxlist.h new file mode 100644 index 0000000..fee0cc0 --- /dev/null +++ b/lib/decoding/osmocom/core/linuxlist.h @@ -0,0 +1,409 @@ +/*! \file linuxlist.h + * + * Simple doubly linked list implementation. + * + * Some of the internal functions ("__xxx") are useful when + * manipulating whole llists rather than single entries, as + * sometimes we already know the next/prev entries and we can + * generate better code by using them directly rather than + * using the generic single-entry routines. + */ + +#pragma once + +/*! \defgroup linuxlist Simple doubly linked list implementation + * @{ + * \file linuxlist.h */ + +#include <stddef.h> + +#if (defined(_WIN16) || defined(_WIN32) || defined(_WIN64)) && !defined(__WINDOWS__) +# define __WINDOWS__ +#endif + +#ifndef inline +# ifndef __WINDOWS__ +# define inline __inline__ +# else +# define inline __inline +# endif +#endif + +static inline void prefetch(const void *x) {;} + +/*! cast a member of a structure out to the containing structure + * + * \param[in] ptr the pointer to the member. + * \param[in] type the type of the container struct this is embedded in. + * \param[in] member the name of the member within the struct. + */ +#define container_of(ptr, type, member) ({ \ + const typeof( ((type *)0)->member ) *__mptr = (ptr); \ + (type *)( (char *)__mptr - offsetof(type, member) );}) + + +/*! + * These are non-NULL pointers that will result in page faults + * under normal circumstances, used to verify that nobody uses + * non-initialized llist entries. + */ +#define LLIST_POISON1 ((void *) 0x00100100) +#define LLIST_POISON2 ((void *) 0x00200200) + +/*! (double) linked list header structure */ +struct llist_head { + /*! Pointer to next and previous item */ + struct llist_head *next, *prev; +}; + +#define LLIST_HEAD_INIT(name) { &(name), &(name) } + +/*! define a statically-initialized \ref llist_head + * \param[in] name Variable name + * + * This is a helper macro that will define a named variable of type + * \ref llist_head and initialize it */ +#define LLIST_HEAD(name) \ + struct llist_head name = LLIST_HEAD_INIT(name) + +/*! initialize a \ref llist_head to point back to self */ +#define INIT_LLIST_HEAD(ptr) do { \ + (ptr)->next = (ptr); (ptr)->prev = (ptr); \ +} while (0) + +/*! Insert a new entry between two known consecutive entries. + * + * This is only for internal llist manipulation where we know + * the prev/next entries already! + */ +static inline void __llist_add(struct llist_head *_new, + struct llist_head *prev, + struct llist_head *next) +{ + next->prev = _new; + _new->next = next; + _new->prev = prev; + prev->next = _new; +} + +/*! add a new entry into a linked list (at head) + * \param _new New entry to be added + * \param head \ref llist_head to add it after + * + * Insert a new entry after the specified head. + * This is good for implementing stacks. + */ +static inline void llist_add(struct llist_head *_new, struct llist_head *head) +{ + __llist_add(_new, head, head->next); +} + +/*! add a new entry into a linked list (at tail) + * \param _new New entry to be added + * \param head Head of linked list to whose tail we shall add \a _new + * + * Insert a new entry before the specified head. + * This is useful for implementing queues. + */ +static inline void llist_add_tail(struct llist_head *_new, struct llist_head *head) +{ + __llist_add(_new, head->prev, head); +} + +/* + * Delete a llist entry by making the prev/next entries + * point to each other. + * + * This is only for internal llist manipulation where we know + * the prev/next entries already! + */ +static inline void __llist_del(struct llist_head * prev, struct llist_head * next) +{ + next->prev = prev; + prev->next = next; +} + +/*! Delete entry from linked list + * \param entry The element to delete from the llist + * + * Note: llist_empty on entry does not return true after this, the entry is + * in an undefined state. + */ +static inline void llist_del(struct llist_head *entry) +{ + __llist_del(entry->prev, entry->next); + entry->next = (struct llist_head *)LLIST_POISON1; + entry->prev = (struct llist_head *)LLIST_POISON2; +} + +/*! Delete entry from linked list and reinitialize it + * \param entry The element to delete from the list + */ +static inline void llist_del_init(struct llist_head *entry) +{ + __llist_del(entry->prev, entry->next); + INIT_LLIST_HEAD(entry); +} + +/*! Delete from one llist and add as another's head + * \param llist The entry to move + * \param head The head that will precede our entry + */ +static inline void llist_move(struct llist_head *llist, struct llist_head *head) +{ + __llist_del(llist->prev, llist->next); + llist_add(llist, head); +} + +/*! Delete from one llist and add as another's tail + * \param llist The entry to move + * \param head The head that will follow our entry + */ +static inline void llist_move_tail(struct llist_head *llist, + struct llist_head *head) +{ + __llist_del(llist->prev, llist->next); + llist_add_tail(llist, head); +} + +/*! Test whether a linked list is empty + * \param[in] head The llist to test. + * \returns 1 if the list is empty, 0 otherwise + */ +static inline int llist_empty(const struct llist_head *head) +{ + return head->next == head; +} + +static inline void __llist_splice(struct llist_head *llist, + struct llist_head *head) +{ + struct llist_head *first = llist->next; + struct llist_head *last = llist->prev; + struct llist_head *at = head->next; + + first->prev = head; + head->next = first; + + last->next = at; + at->prev = last; +} + +/*! Join two llists + * \param llist The new linked list to add + * \param head The place to add \a llist in the other list + */ +static inline void llist_splice(struct llist_head *llist, struct llist_head *head) +{ + if (!llist_empty(llist)) + __llist_splice(llist, head); +} + +/*! join two llists and reinitialise the emptied llist. + * \param llist The new linked list to add. + * \param head The place to add it in the first llist. + * + * The llist at @llist is reinitialised + */ +static inline void llist_splice_init(struct llist_head *llist, + struct llist_head *head) +{ + if (!llist_empty(llist)) { + __llist_splice(llist, head); + INIT_LLIST_HEAD(llist); + } +} + +/*! Get the struct containing this list entry + * \param ptr The \ref llist_head pointer + * \param type The type of the struct this is embedded in + * \param @member The name of the \ref llist_head within the struct + */ +#define llist_entry(ptr, type, member) \ + container_of(ptr, type, member) + +/*! 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 list is expected to be not empty. + */ +#define llist_first_entry(ptr, type, member) \ + llist_entry((ptr)->next, type, member) + +/*! 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 llist_head within the struct. + * + * Note, that list is expected to be not empty. + */ +#define llist_last_entry(ptr, type, member) \ + llist_entry((ptr)->prev, type, member) + +/*! Get the first element from a list, or NULL + * \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 llist_first_entry_or_null(ptr, type, member) \ + (!llist_empty(ptr) ? llist_first_entry(ptr, type, member) : NULL) + +/*! Iterate over a linked list + * \param pos The \ref llist_head to use as a loop counter + * \param head The head of the list over which to iterate + */ +#define llist_for_each(pos, head) \ + for (pos = (head)->next, prefetch(pos->next); pos != (head); \ + pos = pos->next, prefetch(pos->next)) + +/*! Iterate over a llist (no prefetch) + * \param pos The \ref llist_head to use as a loop counter + * \param head The head of the list over which to iterate + * + * This variant differs from llist_for_each() in that it's the + * simplest possible llist iteration code, no prefetching is done. + * Use this for code that knows the llist to be very short (empty + * or 1 entry) most of the time. + */ +#define __llist_for_each(pos, head) \ + for (pos = (head)->next; pos != (head); pos = pos->next) + +/*! Iterate over a llist backwards + * \param pos The \ref llist_head to use as a loop counter + * \param head The head of the list over which to iterate + */ +#define llist_for_each_prev(pos, head) \ + for (pos = (head)->prev, prefetch(pos->prev); pos != (head); \ + pos = pos->prev, prefetch(pos->prev)) + +/*! Iterate over a list; safe against removal of llist entry + * \param pos The \ref llist_head to use as a loop counter + * \param n Another \ref llist_head to use as temporary storage + * \param head The head of the list over which to iterate + */ +#define llist_for_each_safe(pos, n, head) \ + for (pos = (head)->next, n = pos->next; pos != (head); \ + pos = n, n = pos->next) + +/*! Iterate over llist of given type + * \param pos The 'type *' to use as a loop counter + * \param head The head of the list over which to iterate + * \param member The name of the \ref llist_head within struct \a pos + */ +#define llist_for_each_entry(pos, head, member) \ + for (pos = llist_entry((head)->next, typeof(*pos), member), \ + prefetch(pos->member.next); \ + &pos->member != (head); \ + pos = llist_entry(pos->member.next, typeof(*pos), member), \ + prefetch(pos->member.next)) + +/*! Iterate backwards over llist of given type. + * \param pos The 'type *' to use as a loop counter + * \param head The head of the list over which to iterate + * \param member The name of the \ref llist_head within struct \a pos + */ +#define llist_for_each_entry_reverse(pos, head, member) \ + for (pos = llist_entry((head)->prev, typeof(*pos), member), \ + prefetch(pos->member.prev); \ + &pos->member != (head); \ + pos = llist_entry(pos->member.prev, typeof(*pos), member), \ + prefetch(pos->member.prev)) + +/*! iterate over llist of given type continuing after existing + * point + * \param pos The 'type *' to use as a loop counter + * \param head The head of the list over which to iterate + * \param member The name of the \ref llist_head within struct \a pos + */ +#define llist_for_each_entry_continue(pos, head, member) \ + for (pos = llist_entry(pos->member.next, typeof(*pos), member), \ + prefetch(pos->member.next); \ + &pos->member != (head); \ + pos = llist_entry(pos->member.next, typeof(*pos), member), \ + prefetch(pos->member.next)) + +/*! iterate over llist of given type, safe against removal of + * non-consecutive(!) llist entries + * \param pos The 'type *' to use as a loop counter + * \param n Another type * to use as temporary storage + * \param head The head of the list over which to iterate + * \param member The name of the \ref llist_head within struct \a pos + */ +#define llist_for_each_entry_safe(pos, n, head, member) \ + for (pos = llist_entry((head)->next, typeof(*pos), member), \ + n = llist_entry(pos->member.next, typeof(*pos), member); \ + &pos->member != (head); \ + pos = n, n = llist_entry(n->member.next, typeof(*n), member)) + +/** + * llist_for_each_rcu - iterate over an rcu-protected llist + * @pos: the &struct llist_head to use as a loop counter. + * @head: the head for your llist. + */ +#define llist_for_each_rcu(pos, head) \ + for (pos = (head)->next, prefetch(pos->next); pos != (head); \ + pos = pos->next, ({ smp_read_barrier_depends(); 0;}), prefetch(pos->next)) + +#define __llist_for_each_rcu(pos, head) \ + for (pos = (head)->next; pos != (head); \ + pos = pos->next, ({ smp_read_barrier_depends(); 0;})) + +/** + * llist_for_each_safe_rcu - iterate over an rcu-protected llist safe + * against removal of llist entry + * @pos: the &struct llist_head to use as a loop counter. + * @n: another &struct llist_head to use as temporary storage + * @head: the head for your llist. + */ +#define llist_for_each_safe_rcu(pos, n, head) \ + for (pos = (head)->next, n = pos->next; pos != (head); \ + pos = n, ({ smp_read_barrier_depends(); 0;}), n = pos->next) + +/** + * llist_for_each_entry_rcu - iterate over rcu llist of given type + * @pos: the type * to use as a loop counter. + * @head: the head for your llist. + * @member: the name of the llist_struct within the struct. + */ +#define llist_for_each_entry_rcu(pos, head, member) \ + for (pos = llist_entry((head)->next, typeof(*pos), member), \ + prefetch(pos->member.next); \ + &pos->member != (head); \ + pos = llist_entry(pos->member.next, typeof(*pos), member), \ + ({ smp_read_barrier_depends(); 0;}), \ + prefetch(pos->member.next)) + + +/** + * llist_for_each_continue_rcu - iterate over an rcu-protected llist + * continuing after existing point. + * @pos: the &struct llist_head to use as a loop counter. + * @head: the head for your llist. + */ +#define llist_for_each_continue_rcu(pos, head) \ + for ((pos) = (pos)->next, prefetch((pos)->next); (pos) != (head); \ + (pos) = (pos)->next, ({ smp_read_barrier_depends(); 0;}), prefetch((pos)->next)) + +/*! count nr of llist items by iterating. + * \param head The llist head to count items of. + * \returns Number of items. + * + * This function is not efficient, mostly useful for small lists and non time + * critical cases like unit tests. + */ +static inline unsigned int llist_count(struct llist_head *head) +{ + struct llist_head *entry; + unsigned int i = 0; + llist_for_each(entry, head) + i++; + return i; +} + +/*! + * @} + */ |