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haproxy/include/common/mini-clist.h
Olivier Houchard 804ef244c6 MINOR: lists: Fix alignement of \ when relevant. 
Make sure all the \ are properly aligned in macroes, this contains no
functional change.
2019-10-11 16:56:25 +02:00

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/*
* include/common/mini-clist.h
* Circular list manipulation macros and structures.
*
* Copyright (C) 2002-2014 Willy Tarreau - w@1wt.eu
*
* This library is free software; you can redistribute it and/or
* modify it under the terms of the GNU Lesser General Public
* License as published by the Free Software Foundation, version 2.1
* exclusively.
*
* This library is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
* Lesser General Public License for more details.
*
* You should have received a copy of the GNU Lesser General Public
* License along with this library; if not, write to the Free Software
* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
*/
#ifndef _COMMON_MINI_CLIST_H
#define _COMMON_MINI_CLIST_H
#include <common/config.h>
/* these are circular or bidirectionnal lists only. Each list pointer points to
* another list pointer in a structure, and not the structure itself. The
* pointer to the next element MUST be the first one so that the list is easily
* cast as a single linked list or pointer.
*/
struct list {
struct list *n; /* next */
struct list *p; /* prev */
};
/* This is similar to struct list, but we want to be sure the compiler will
* yell at you if you use macroes for one when you're using the other. You have
* to expicitely cast if that's really what you want to do.
*/
struct mt_list {
struct mt_list *next;
struct mt_list *prev;
};
/* a back-ref is a pointer to a target list entry. It is used to detect when an
* element being deleted is currently being tracked by another user. The best
* example is a user dumping the session table. The table does not fit in the
* output buffer so we have to set a mark on a session and go on later. But if
* that marked session gets deleted, we don't want the user's pointer to go in
* the wild. So we can simply link this user's request to the list of this
* session's users, and put a pointer to the list element in ref, that will be
* used as the mark for next iteration.
*/
struct bref {
struct list users;
struct list *ref; /* pointer to the target's list entry */
};
/* a word list is a generic list with a pointer to a string in each element. */
struct wordlist {
struct list list;
char *s;
};
/* this is the same as above with an additional pointer to a condition. */
struct cond_wordlist {
struct list list;
void *cond;
char *s;
};
/* First undefine some macros which happen to also be defined on OpenBSD,
* in sys/queue.h, used by sys/event.h
*/
#undef LIST_HEAD
#undef LIST_INIT
#undef LIST_NEXT
/* ILH = Initialized List Head : used to prevent gcc from moving an empty
* list to BSS. Some older version tend to trim all the array and cause
* corruption.
*/
#define ILH { .n = (struct list *)1, .p = (struct list *)2 }
#define LIST_HEAD(a) ((void *)(&(a)))
#define LIST_INIT(l) ((l)->n = (l)->p = (l))
#define LIST_HEAD_INIT(l) { &l, &l }
/* adds an element at the beginning of a list ; returns the element */
#define LIST_ADD(lh, el) ({ (el)->n = (lh)->n; (el)->n->p = (lh)->n = (el); (el)->p = (lh); (el); })
/* adds an element at the end of a list ; returns the element */
#define LIST_ADDQ(lh, el) ({ (el)->p = (lh)->p; (el)->p->n = (lh)->p = (el); (el)->n = (lh); (el); })
/* adds the contents of a list <old> at the beginning of another list <new>. The old list head remains untouched. */
#define LIST_SPLICE(new, old) do { \
if (!LIST_ISEMPTY(old)) { \
(old)->p->n = (new)->n; (old)->n->p = (new); \
(new)->n->p = (old)->p; (new)->n = (old)->n; \
} \
} while (0)
/* adds the contents of a list whose first element is <old> and last one is
* <old->prev> at the end of another list <new>. The old list DOES NOT have
* any head here.
*/
#define LIST_SPLICE_END_DETACHED(new, old) do { \
typeof(new) __t; \
(new)->p->n = (old); \
(old)->p->n = (new); \
__t = (old)->p; \
(old)->p = (new)->p; \
(new)->p = __t; \
} while (0)
/* removes an element from a list and returns it */
#define LIST_DEL(el) ({ typeof(el) __ret = (el); (el)->n->p = (el)->p; (el)->p->n = (el)->n; (__ret); })
/* removes an element from a list, initializes it and returns it.
* This is faster than LIST_DEL+LIST_INIT as we avoid reloading the pointers.
*/
#define LIST_DEL_INIT(el) ({ \
typeof(el) __ret = (el); \
typeof(__ret->n) __n = __ret->n; \
typeof(__ret->p) __p = __ret->p; \
__n->p = __p; __p->n = __n; \
__ret->n = __ret->p = __ret; \
__ret; \
})
/* returns a pointer of type <pt> to a structure containing a list head called
* <el> at address <lh>. Note that <lh> can be the result of a function or macro
* since it's used only once.
* Example: LIST_ELEM(cur_node->args.next, struct node *, args)
*/
#define LIST_ELEM(lh, pt, el) ((pt)(((void *)(lh)) - ((void *)&((pt)NULL)->el)))
/* checks if the list head <lh> is empty or not */
#define LIST_ISEMPTY(lh) ((lh)->n == (lh))
/* checks if the list element <el> was added to a list or not. This only
* works when detached elements are reinitialized (using LIST_DEL_INIT)
*/
#define LIST_ADDED(el) ((el)->n != (el))
/* returns a pointer of type <pt> to a structure following the element
* which contains list head <lh>, which is known as element <el> in
* struct pt.
* Example: LIST_NEXT(args, struct node *, list)
*/
#define LIST_NEXT(lh, pt, el) (LIST_ELEM((lh)->n, pt, el))
/* returns a pointer of type <pt> to a structure preceding the element
* which contains list head <lh>, which is known as element <el> in
* struct pt.
*/
#undef LIST_PREV
#define LIST_PREV(lh, pt, el) (LIST_ELEM((lh)->p, pt, el))
/*
* Simpler FOREACH_ITEM macro inspired from Linux sources.
* Iterates <item> through a list of items of type "typeof(*item)" which are
* linked via a "struct list" member named <member>. A pointer to the head of
* the list is passed in <list_head>. No temporary variable is needed. Note
* that <item> must not be modified during the loop.
* Example: list_for_each_entry(cur_acl, known_acl, list) { ... };
*/
#define list_for_each_entry(item, list_head, member) \
for (item = LIST_ELEM((list_head)->n, typeof(item), member); \
&item->member != (list_head); \
item = LIST_ELEM(item->member.n, typeof(item), member))
/*
* Same as list_for_each_entry but starting from current point
* Iterates <item> through the list starting from <item>
* It's basically the same macro but without initializing item to the head of
* the list.
*/
#define list_for_each_entry_from(item, list_head, member) \
for ( ; &item->member != (list_head); \
item = LIST_ELEM(item->member.n, typeof(item), member))
/*
* Simpler FOREACH_ITEM_SAFE macro inspired from Linux sources.
* Iterates <item> through a list of items of type "typeof(*item)" which are
* linked via a "struct list" member named <member>. A pointer to the head of
* the list is passed in <list_head>. A temporary variable <back> of same type
* as <item> is needed so that <item> may safely be deleted if needed.
* Example: list_for_each_entry_safe(cur_acl, tmp, known_acl, list) { ... };
*/
#define list_for_each_entry_safe(item, back, list_head, member) \
for (item = LIST_ELEM((list_head)->n, typeof(item), member), \
back = LIST_ELEM(item->member.n, typeof(item), member); \
&item->member != (list_head); \
item = back, back = LIST_ELEM(back->member.n, typeof(back), member))
/*
* Same as list_for_each_entry_safe but starting from current point
* Iterates <item> through the list starting from <item>
* It's basically the same macro but without initializing item to the head of
* the list.
*/
#define list_for_each_entry_safe_from(item, back, list_head, member) \
for (back = LIST_ELEM(item->member.n, typeof(item), member); \
&item->member != (list_head); \
item = back, back = LIST_ELEM(back->member.n, typeof(back), member))
#include <common/hathreads.h>
#define MT_LIST_BUSY ((struct mt_list *)1)
/*
* Locked version of list manipulation macros.
* It is OK to use those concurrently from multiple threads, as long as the
* list is only used with the locked variants.
*/
/*
* Add an item at the beginning of a list.
* Returns 1 if we added the item, 0 otherwise (because it was already in a
* list).
*/
#define MT_LIST_ADD(_lh, _el) \
({ \
int _ret = 0; \
struct mt_list *lh = (_lh), *el = (_el); \
do { \
while (1) { \
struct mt_list *n; \
struct mt_list *p; \
n = _HA_ATOMIC_XCHG(&(lh)->next, MT_LIST_BUSY); \
if (n == MT_LIST_BUSY) \
continue; \
p = _HA_ATOMIC_XCHG(&n->prev, MT_LIST_BUSY); \
if (p == MT_LIST_BUSY) { \
(lh)->next = n; \
__ha_barrier_store(); \
continue; \
} \
if ((el)->next != (el) || (el)->prev != (el)) { \
(n)->prev = p; \
(lh)->next = n; \
break; \
} \
(el)->next = n; \
(el)->prev = p; \
__ha_barrier_store(); \
n->prev = (el); \
__ha_barrier_store(); \
p->next = (el); \
__ha_barrier_store(); \
_ret = 1; \
break; \
} \
} while (0); \
(_ret); \
})
/*
* Add an item at the end of a list.
* Returns 1 if we added the item, 0 otherwise (because it was already in a
* list).
*/
#define MT_LIST_ADDQ(_lh, _el) \
({ \
int _ret = 0; \
struct mt_list *lh = (_lh), *el = (_el); \
do { \
while (1) { \
struct mt_list *n; \
struct mt_list *p; \
p = _HA_ATOMIC_XCHG(&(lh)->prev, MT_LIST_BUSY); \
if (p == MT_LIST_BUSY) \
continue; \
n = _HA_ATOMIC_XCHG(&p->next, MT_LIST_BUSY); \
if (n == MT_LIST_BUSY) { \
(lh)->prev = p; \
__ha_barrier_store(); \
continue; \
} \
if ((el)->next != (el) || (el)->prev != (el)) { \
p->next = n; \
(lh)->prev = p; \
break; \
} \
(el)->next = n; \
(el)->prev = p; \
__ha_barrier_store(); \
p->next = (el); \
__ha_barrier_store(); \
n->prev = (el); \
__ha_barrier_store(); \
_ret = 1; \
break; \
} \
} while (0); \
(_ret); \
})
/*
* Detach a list from its head. A pointer to the first element is returned
* and the list is closed. If the list was empty, NULL is returned. This may
* exclusively be used with lists modified by MT_LIST_ADD/MT_LIST_ADDQ. This
* is incompatible with MT_LIST_DEL run concurrently.
*/
#define MT_LIST_BEHEAD(_lh) ({ \
struct mt_list *lh = (_lh); \
struct mt_list *_n; \
struct mt_list *_p; \
while (1) { \
_p = _HA_ATOMIC_XCHG(&(lh)->prev, MT_LIST_BUSY); \
if (_p == MT_LIST_BUSY) \
continue; \
if (_p == (lh)) { \
(lh)->prev = _p; \
_n = NULL; \
break; \
} \
_n = _HA_ATOMIC_XCHG(&(lh)->next, MT_LIST_BUSY); \
if (_n == MT_LIST_BUSY) { \
(lh)->prev = _p; \
__ha_barrier_store(); \
continue; \
} \
if (_n == (lh)) { \
(lh)->next = _n; \
(lh)->prev = _p; \
_n = NULL; \
break; \
} \
(lh)->next = (lh); \
(lh)->prev = (lh); \
_n->prev = _p; \
_p->next = _n; \
__ha_barrier_store(); \
break; \
} \
(_n); \
})
/* Remove an item from a list.
* Returns 1 if we removed the item, 0 otherwise (because it was in no list).
*/
#define MT_LIST_DEL(_el) \
({ \
int _ret = 0; \
struct mt_list *el = (_el); \
do { \
while (1) { \
struct mt_list *n, *n2; \
struct mt_list *p, *p2 = NULL; \
n = _HA_ATOMIC_XCHG(&(el)->next, MT_LIST_BUSY); \
if (n == MT_LIST_BUSY) \
continue; \
p = _HA_ATOMIC_XCHG(&(el)->prev, MT_LIST_BUSY); \
if (p == MT_LIST_BUSY) { \
(el)->next = n; \
__ha_barrier_store(); \
continue; \
} \
if (p != (el)) { \
p2 = _HA_ATOMIC_XCHG(&p->next, MT_LIST_BUSY);\
if (p2 == MT_LIST_BUSY) { \
(el)->prev = p; \
(el)->next = n; \
__ha_barrier_store(); \
continue; \
} \
} \
if (n != (el)) { \
n2 = _HA_ATOMIC_XCHG(&n->prev, MT_LIST_BUSY);\
if (n2 == MT_LIST_BUSY) { \
if (p2 != NULL) \
p->next = p2; \
(el)->prev = p; \
(el)->next = n; \
__ha_barrier_store(); \
continue; \
} \
} \
n->prev = p; \
p->next = n; \
if (p != (el) && n != (el)) \
_ret = 1; \
__ha_barrier_store(); \
(el)->prev = (el); \
(el)->next = (el); \
__ha_barrier_store(); \
break; \
} \
} while (0); \
(_ret); \
})
/* Remove the first element from the list, and return it */
#define MT_LIST_POP(_lh, pt, el) \
({ \
void *_ret; \
struct mt_list *lh = (_lh); \
while (1) { \
struct mt_list *n, *n2; \
struct mt_list *p, *p2; \
n = _HA_ATOMIC_XCHG(&(lh)->next, MT_LIST_BUSY); \
if (n == MT_LIST_BUSY) \
continue; \
if (n == (lh)) { \
(lh)->next = lh; \
__ha_barrier_store(); \
_ret = NULL; \
break; \
} \
p = _HA_ATOMIC_XCHG(&n->prev, MT_LIST_BUSY); \
if (p == MT_LIST_BUSY) { \
(lh)->next = n; \
__ha_barrier_store(); \
continue; \
} \
n2 = _HA_ATOMIC_XCHG(&n->next, MT_LIST_BUSY); \
if (n2 == MT_LIST_BUSY) { \
n->prev = p; \
__ha_barrier_store(); \
(lh)->next = n; \
__ha_barrier_store(); \
continue; \
} \
p2 = _HA_ATOMIC_XCHG(&n2->prev, MT_LIST_BUSY); \
if (p2 == MT_LIST_BUSY) { \
n->next = n2; \
n->prev = p; \
__ha_barrier_store(); \
(lh)->next = n; \
__ha_barrier_store(); \
continue; \
} \
(lh)->next = n2; \
(n2)->prev = (lh); \
__ha_barrier_store(); \
(n)->prev = (n); \
(n)->next = (n); \
__ha_barrier_store(); \
_ret = MT_LIST_ELEM(n, pt, el); \
break; \
} \
(_ret); \
})
#define MT_LIST_HEAD(a) ((void *)(&(a)))
#define MT_LIST_INIT(l) ((l)->next = (l)->prev = (l))
#define MT_LIST_HEAD_INIT(l) { &l, &l }
/* returns a pointer of type <pt> to a structure containing a list head called
* <el> at address <lh>. Note that <lh> can be the result of a function or macro
* since it's used only once.
* Example: MT_LIST_ELEM(cur_node->args.next, struct node *, args)
*/
#define MT_LIST_ELEM(lh, pt, el) ((pt)(((void *)(lh)) - ((void *)&((pt)NULL)->el)))
/* checks if the list head <lh> is empty or not */
#define MT_LIST_ISEMPTY(lh) ((lh)->next == (lh))
/* returns a pointer of type <pt> to a structure following the element
* which contains list head <lh>, which is known as element <el> in
* struct pt.
* Example: MT_LIST_NEXT(args, struct node *, list)
*/
#define MT_LIST_NEXT(lh, pt, el) (MT_LIST_ELEM((lh)->next, pt, el))
/* returns a pointer of type <pt> to a structure preceding the element
* which contains list head <lh>, which is known as element <el> in
* struct pt.
*/
#undef MT_LIST_PREV
#define MT_LIST_PREV(lh, pt, el) (MT_LIST_ELEM((lh)->prev, pt, el))
/* checks if the list element <el> was added to a list or not. This only
* works when detached elements are reinitialized (using LIST_DEL_INIT)
*/
#define MT_LIST_ADDED(el) ((el)->next != (el))
/* Lock an element in the list, to be sure it won't be removed.
* It needs to be synchronized somehow to be sure it's not removed
* from the list in the meanwhile.
* This returns a struct mt_list, that will be needed at unlock time.
*/
#define MT_LIST_LOCK_ELT(_el) \
({ \
struct mt_list ret; \
struct mt_liet *el = (_el); \
while (1) { \
struct mt_list *n, *n2; \
struct mt_list *p, *p2 = NULL; \
n = _HA_ATOMIC_XCHG(&(el)->next, MT_LIST_BUSY); \
if (n == MT_LIST_BUSY) \
continue; \
p = _HA_ATOMIC_XCHG(&(el)->prev, MT_LIST_BUSY); \
if (p == MT_LIST_BUSY) { \
(el)->next = n; \
__ha_barrier_store(); \
continue; \
} \
if (p != (el)) { \
p2 = _HA_ATOMIC_XCHG(&p->next, MT_LIST_BUSY);\
if (p2 == MT_LIST_BUSY) { \
(el)->prev = p; \
(el)->next = n; \
__ha_barrier_store(); \
continue; \
} \
} \
if (n != (el)) { \
n2 = _HA_ATOMIC_XCHG(&n->prev, MT_LIST_BUSY);\
if (n2 == MT_LIST_BUSY) { \
if (p2 != NULL) \
p->next = p2; \
(el)->prev = p; \
(el)->next = n; \
__ha_barrier_store(); \
continue; \
} \
} \
ret.next = n; \
ret.prev = p; \
break; \
} \
ret; \
})
/* Unlock an element previously locked by MT_LIST_LOCK_ELT. "np" is the
* struct mt_list returned by MT_LIST_LOCK_ELT().
*/
#define MT_LIST_UNLOCK_ELT(_el, np) \
do { \
struct mt_list *n = (np).next, *p = (np).prev; \
struct mt_list *el = (_el); \
(el)->next = n; \
(el)->prev = p; \
if (n != (el)) \
n->prev = (el); \
if (p != (el)) \
p->next = (el); \
} while (0)
/* Internal macroes for the foreach macroes */
#define _MT_LIST_UNLOCK_NEXT(el, np) \
do { \
struct mt_list *n = (np); \
(el)->next = n; \
if (n != (el)) \
n->prev = (el); \
} while (0)
/* Internal macroes for the foreach macroes */
#define _MT_LIST_UNLOCK_PREV(el, np) \
do { \
struct mt_list *p = (np); \
(el)->prev = p; \
if (p != (el)) \
p->next = (el); \
} while (0)
#define _MT_LIST_LOCK_NEXT(el) \
({ \
struct mt_list *n = NULL; \
while (1) { \
struct mt_list *n2; \
n = _HA_ATOMIC_XCHG(&((el)->next), MT_LIST_BUSY); \
if (n == MT_LIST_BUSY) \
continue; \
if (n != (el)) { \
n2 = _HA_ATOMIC_XCHG(&n->prev, MT_LIST_BUSY);\
if (n2 == MT_LIST_BUSY) { \
(el)->next = n; \
__ha_barrier_store(); \
continue; \
} \
} \
break; \
} \
n; \
})
#define _MT_LIST_LOCK_PREV(el) \
({ \
struct mt_list *p = NULL; \
while (1) { \
struct mt_list *p2; \
p = _HA_ATOMIC_XCHG(&((el)->prev), MT_LIST_BUSY); \
if (p == MT_LIST_BUSY) \
continue; \
if (p != (el)) { \
p2 = _HA_ATOMIC_XCHG(&p->next, MT_LIST_BUSY);\
if (p2 == MT_LIST_BUSY) { \
(el)->prev = p; \
__ha_barrier_store(); \
continue; \
} \
} \
break; \
} \
p; \
})
#define _MT_LIST_RELINK_DELETED(elt2) \
do { \
struct mt_list *n = elt2.next, *p = elt2.prev; \
n->prev = p; \
p->next = n; \
} while (0);
/* Equivalent of MT_LIST_DEL(), to be used when parsing the list with mt_list_entry_for_each_safe().
* It should be the element currently parsed (tmpelt1)
*/
#define MT_LIST_DEL_SAFE(_el) \
do { \
struct mt_list *el = (_el); \
(el)->prev = (el); \
(el)->next = (el); \
(el) = NULL; \
} while (0)
/* Simpler FOREACH_ITEM_SAFE macro inspired from Linux sources.
* Iterates <item> through a list of items of type "typeof(*item)" which are
* linked via a "struct list" member named <member>. A pointer to the head of
* the list is passed in <list_head>. A temporary variable <back> of same type
* as <item> is needed so that <item> may safely be deleted if needed.
* tmpelt1 is a temporary struct mt_list *, and tmpelt2 is a temporary
* struct mt_list, used internally, both are needed for MT_LIST_DEL_SAFE.
* Example: list_for_each_entry_safe(cur_acl, tmp, known_acl, list, elt1, elt2)
* { ... };
* If you want to remove the current element, please use MT_LIST_DEL_SAFE.
*/
#define mt_list_for_each_entry_safe(item, list_head, member, tmpelt, tmpelt2) \
for ((tmpelt) = NULL; (tmpelt) != MT_LIST_BUSY; ({ \
if (tmpelt) { \
if (tmpelt2.prev) \
MT_LIST_UNLOCK_ELT(tmpelt, tmpelt2); \
else \
_MT_LIST_UNLOCK_NEXT(tmpelt, tmpelt2.next); \
} else \
_MT_LIST_RELINK_DELETED(tmpelt2); \
(tmpelt) = MT_LIST_BUSY; \
})) \
for ((tmpelt) = (list_head), (tmpelt2).prev = NULL, (tmpelt2).next = _MT_LIST_LOCK_NEXT(tmpelt); ({ \
(item) = MT_LIST_ELEM((tmpelt2.next), typeof(item), member); \
if (&item->member != (list_head)) { \
if (tmpelt2.prev != &item->member) \
tmpelt2.next = _MT_LIST_LOCK_NEXT(&item->member); \
else \
tmpelt2.next = tmpelt; \
if (tmpelt != NULL) { \
if (tmpelt2.prev) \
_MT_LIST_UNLOCK_PREV(tmpelt, tmpelt2.prev); \
tmpelt2.prev = tmpelt; \
} \
(tmpelt) = &item->member; \
} \
}), \
&item->member != (list_head);)
#endif /* _COMMON_MINI_CLIST_H */
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