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859dc80f94
Instead of using the same type for regular linked lists and "autolocked" linked lists, use a separate type, "struct mt_list", for the autolocked one, and introduce a set of macros, similar to the LIST_* macros, with the MT_ prefix. When we use the same entry for both regular list and autolocked list, as is done for the "list" field in struct connection, we know have to explicitely cast it to struct mt_list when using MT_ macros.
392 lines
17 KiB
C
392 lines
17 KiB
C
/*
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* include/common/mini-clist.h
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* Circular list manipulation macros and structures.
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*
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* Copyright (C) 2002-2014 Willy Tarreau - w@1wt.eu
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*
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* This library is free software; you can redistribute it and/or
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* modify it under the terms of the GNU Lesser General Public
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* License as published by the Free Software Foundation, version 2.1
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* exclusively.
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*
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* This library is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
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* Lesser General Public License for more details.
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*
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* You should have received a copy of the GNU Lesser General Public
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* License along with this library; if not, write to the Free Software
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* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
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*/
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#ifndef _COMMON_MINI_CLIST_H
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#define _COMMON_MINI_CLIST_H
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#include <common/config.h>
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/* these are circular or bidirectionnal lists only. Each list pointer points to
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* another list pointer in a structure, and not the structure itself. The
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* pointer to the next element MUST be the first one so that the list is easily
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* cast as a single linked list or pointer.
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*/
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struct list {
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struct list *n; /* next */
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struct list *p; /* prev */
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};
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/* This is similar to struct list, but we want to be sure the compiler will
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* yell at you if you use macroes for one when you're using the other. You have
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* to expicitely cast if that's really what you want to do.
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*/
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struct mt_list {
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struct mt_list *next;
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struct mt_list *prev;
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};
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/* a back-ref is a pointer to a target list entry. It is used to detect when an
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* element being deleted is currently being tracked by another user. The best
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* example is a user dumping the session table. The table does not fit in the
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* output buffer so we have to set a mark on a session and go on later. But if
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* that marked session gets deleted, we don't want the user's pointer to go in
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* the wild. So we can simply link this user's request to the list of this
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* session's users, and put a pointer to the list element in ref, that will be
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* used as the mark for next iteration.
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*/
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struct bref {
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struct list users;
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struct list *ref; /* pointer to the target's list entry */
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};
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/* a word list is a generic list with a pointer to a string in each element. */
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struct wordlist {
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struct list list;
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char *s;
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};
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/* this is the same as above with an additional pointer to a condition. */
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struct cond_wordlist {
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struct list list;
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void *cond;
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char *s;
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};
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/* First undefine some macros which happen to also be defined on OpenBSD,
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* in sys/queue.h, used by sys/event.h
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*/
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#undef LIST_HEAD
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#undef LIST_INIT
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#undef LIST_NEXT
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/* ILH = Initialized List Head : used to prevent gcc from moving an empty
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* list to BSS. Some older version tend to trim all the array and cause
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* corruption.
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*/
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#define ILH { .n = (struct list *)1, .p = (struct list *)2 }
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#define LIST_HEAD(a) ((void *)(&(a)))
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#define LIST_INIT(l) ((l)->n = (l)->p = (l))
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#define LIST_HEAD_INIT(l) { &l, &l }
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/* adds an element at the beginning of a list ; returns the element */
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#define LIST_ADD(lh, el) ({ (el)->n = (lh)->n; (el)->n->p = (lh)->n = (el); (el)->p = (lh); (el); })
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/* adds an element at the end of a list ; returns the element */
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#define LIST_ADDQ(lh, el) ({ (el)->p = (lh)->p; (el)->p->n = (lh)->p = (el); (el)->n = (lh); (el); })
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/* adds the contents of a list <old> at the beginning of another list <new>. The old list head remains untouched. */
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#define LIST_SPLICE(new, old) do { \
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if (!LIST_ISEMPTY(old)) { \
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(old)->p->n = (new)->n; (old)->n->p = (new); \
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(new)->n->p = (old)->p; (new)->n = (old)->n; \
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} \
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} while (0)
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/* removes an element from a list and returns it */
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#define LIST_DEL(el) ({ typeof(el) __ret = (el); (el)->n->p = (el)->p; (el)->p->n = (el)->n; (__ret); })
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/* removes an element from a list, initializes it and returns it.
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* This is faster than LIST_DEL+LIST_INIT as we avoid reloading the pointers.
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*/
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#define LIST_DEL_INIT(el) ({ \
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typeof(el) __ret = (el); \
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typeof(__ret->n) __n = __ret->n; \
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typeof(__ret->p) __p = __ret->p; \
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__n->p = __p; __p->n = __n; \
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__ret->n = __ret->p = __ret; \
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__ret; \
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})
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/* returns a pointer of type <pt> to a structure containing a list head called
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* <el> at address <lh>. Note that <lh> can be the result of a function or macro
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* since it's used only once.
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* Example: LIST_ELEM(cur_node->args.next, struct node *, args)
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*/
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#define LIST_ELEM(lh, pt, el) ((pt)(((void *)(lh)) - ((void *)&((pt)NULL)->el)))
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/* checks if the list head <lh> is empty or not */
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#define LIST_ISEMPTY(lh) ((lh)->n == (lh))
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/* checks if the list element <el> was added to a list or not. This only
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* works when detached elements are reinitialized (using LIST_DEL_INIT)
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*/
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#define LIST_ADDED(el) ((el)->n != (el))
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/* returns a pointer of type <pt> to a structure following the element
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* which contains list head <lh>, which is known as element <el> in
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* struct pt.
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* Example: LIST_NEXT(args, struct node *, list)
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*/
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#define LIST_NEXT(lh, pt, el) (LIST_ELEM((lh)->n, pt, el))
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/* returns a pointer of type <pt> to a structure preceding the element
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* which contains list head <lh>, which is known as element <el> in
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* struct pt.
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*/
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#undef LIST_PREV
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#define LIST_PREV(lh, pt, el) (LIST_ELEM((lh)->p, pt, el))
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/*
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* Simpler FOREACH_ITEM macro inspired from Linux sources.
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* Iterates <item> through a list of items of type "typeof(*item)" which are
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* linked via a "struct list" member named <member>. A pointer to the head of
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* the list is passed in <list_head>. No temporary variable is needed. Note
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* that <item> must not be modified during the loop.
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* Example: list_for_each_entry(cur_acl, known_acl, list) { ... };
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*/
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#define list_for_each_entry(item, list_head, member) \
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for (item = LIST_ELEM((list_head)->n, typeof(item), member); \
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&item->member != (list_head); \
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item = LIST_ELEM(item->member.n, typeof(item), member))
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/*
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* Same as list_for_each_entry but starting from current point
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* Iterates <item> through the list starting from <item>
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* It's basically the same macro but without initializing item to the head of
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* the list.
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*/
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#define list_for_each_entry_from(item, list_head, member) \
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for ( ; &item->member != (list_head); \
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item = LIST_ELEM(item->member.n, typeof(item), member))
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/*
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* Simpler FOREACH_ITEM_SAFE macro inspired from Linux sources.
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* Iterates <item> through a list of items of type "typeof(*item)" which are
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* linked via a "struct list" member named <member>. A pointer to the head of
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* the list is passed in <list_head>. A temporary variable <back> of same type
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* as <item> is needed so that <item> may safely be deleted if needed.
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* Example: list_for_each_entry_safe(cur_acl, tmp, known_acl, list) { ... };
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*/
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#define list_for_each_entry_safe(item, back, list_head, member) \
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for (item = LIST_ELEM((list_head)->n, typeof(item), member), \
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back = LIST_ELEM(item->member.n, typeof(item), member); \
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&item->member != (list_head); \
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item = back, back = LIST_ELEM(back->member.n, typeof(back), member))
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/*
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* Same as list_for_each_entry_safe but starting from current point
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* Iterates <item> through the list starting from <item>
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* It's basically the same macro but without initializing item to the head of
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* the list.
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*/
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#define list_for_each_entry_safe_from(item, back, list_head, member) \
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for (back = LIST_ELEM(item->member.n, typeof(item), member); \
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&item->member != (list_head); \
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item = back, back = LIST_ELEM(back->member.n, typeof(back), member))
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#include <common/hathreads.h>
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#define MT_LIST_BUSY ((struct mt_list *)1)
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/*
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* Locked version of list manipulation macros.
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* It is OK to use those concurrently from multiple threads, as long as the
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* list is only used with the locked variants. The only "unlocked" macro you
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* can use with a locked list is LIST_INIT.
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*/
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#define MT_LIST_ADD(lh, el) \
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do { \
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while (1) { \
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struct mt_list *n; \
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struct mt_list *p; \
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n = _HA_ATOMIC_XCHG(&(lh)->next, MT_LIST_BUSY); \
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if (n == MT_LIST_BUSY) \
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continue; \
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p = _HA_ATOMIC_XCHG(&n->prev, MT_LIST_BUSY); \
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if (p == MT_LIST_BUSY) { \
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(lh)->next = n; \
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__ha_barrier_store(); \
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continue; \
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} \
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(el)->next = n; \
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(el)->prev = p; \
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__ha_barrier_store(); \
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n->prev = (el); \
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__ha_barrier_store(); \
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p->next = (el); \
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__ha_barrier_store(); \
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break; \
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} \
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} while (0)
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#define MT_LIST_ADDQ(lh, el) \
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do { \
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while (1) { \
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struct mt_list *n; \
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struct mt_list *p; \
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p = _HA_ATOMIC_XCHG(&(lh)->prev, MT_LIST_BUSY); \
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if (p == MT_LIST_BUSY) \
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continue; \
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n = _HA_ATOMIC_XCHG(&p->next, MT_LIST_BUSY); \
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if (n == MT_LIST_BUSY) { \
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(lh)->prev = p; \
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__ha_barrier_store(); \
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continue; \
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} \
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(el)->next = n; \
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(el)->prev = p; \
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__ha_barrier_store(); \
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p->next = (el); \
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__ha_barrier_store(); \
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n->prev = (el); \
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__ha_barrier_store(); \
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break; \
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} \
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} while (0)
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#define MT_LIST_DEL(el) \
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do { \
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while (1) { \
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struct mt_list *n, *n2; \
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struct mt_list *p, *p2 = NULL; \
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n = _HA_ATOMIC_XCHG(&(el)->next, MT_LIST_BUSY); \
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if (n == MT_LIST_BUSY) \
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continue; \
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p = _HA_ATOMIC_XCHG(&(el)->prev, MT_LIST_BUSY); \
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if (p == MT_LIST_BUSY) { \
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(el)->next = n; \
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__ha_barrier_store(); \
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continue; \
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} \
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if (p != (el)) { \
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p2 = _HA_ATOMIC_XCHG(&p->next, MT_LIST_BUSY);\
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if (p2 == MT_LIST_BUSY) { \
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(el)->prev = p; \
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(el)->next = n; \
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__ha_barrier_store(); \
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continue; \
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} \
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} \
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if (n != (el)) { \
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n2 = _HA_ATOMIC_XCHG(&n->prev, MT_LIST_BUSY);\
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if (n2 == MT_LIST_BUSY) { \
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if (p2 != NULL) \
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p->next = p2; \
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(el)->prev = p; \
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(el)->next = n; \
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__ha_barrier_store(); \
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continue; \
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} \
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} \
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n->prev = p; \
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p->next = n; \
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__ha_barrier_store(); \
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(el)->prev = (el); \
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(el)->next = (el); \
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__ha_barrier_store(); \
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break; \
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} \
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} while (0)
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/* Remove the first element from the list, and return it */
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#define MT_LIST_POP(lh, pt, el) \
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({ \
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void *_ret; \
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while (1) { \
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struct mt_list *n, *n2; \
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struct mt_list *p, *p2; \
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n = _HA_ATOMIC_XCHG(&(lh)->next, MT_LIST_BUSY); \
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if (n == MT_LIST_BUSY) \
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continue; \
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if (n == (lh)) { \
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(lh)->next = lh; \
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__ha_barrier_store(); \
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_ret = NULL; \
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break; \
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} \
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p = _HA_ATOMIC_XCHG(&n->prev, MT_LIST_BUSY); \
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if (p == MT_LIST_BUSY) { \
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(lh)->next = n; \
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__ha_barrier_store(); \
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continue; \
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} \
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n2 = _HA_ATOMIC_XCHG(&n->next, MT_LIST_BUSY); \
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if (n2 == MT_LIST_BUSY) { \
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n->prev = p; \
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__ha_barrier_store(); \
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(lh)->next = n; \
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__ha_barrier_store(); \
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continue; \
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} \
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p2 = _HA_ATOMIC_XCHG(&n2->prev, MT_LIST_BUSY); \
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if (p2 == MT_LIST_BUSY) { \
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n->next = n2; \
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n->prev = p; \
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__ha_barrier_store(); \
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(lh)->next = n; \
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__ha_barrier_store(); \
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continue; \
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} \
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(lh)->next = n2; \
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(n2)->prev = (lh); \
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__ha_barrier_store(); \
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(n)->prev = (n); \
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(n)->next = (n); \
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__ha_barrier_store(); \
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_ret = MT_LIST_ELEM(n, pt, el); \
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break; \
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} \
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(_ret); \
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})
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#define MT_LIST_HEAD(a) ((void *)(&(a)))
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#define MT_LIST_INIT(l) ((l)->next = (l)->prev = (l))
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#define MT_LIST_HEAD_INIT(l) { &l, &l }
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/* returns a pointer of type <pt> to a structure containing a list head called
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* <el> at address <lh>. Note that <lh> can be the result of a function or macro
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* since it's used only once.
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* Example: MT_LIST_ELEM(cur_node->args.next, struct node *, args)
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*/
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#define MT_LIST_ELEM(lh, pt, el) ((pt)(((void *)(lh)) - ((void *)&((pt)NULL)->el)))
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/* checks if the list head <lh> is empty or not */
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#define MT_LIST_ISEMPTY(lh) ((lh)->next == (lh))
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/* returns a pointer of type <pt> to a structure following the element
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* which contains list head <lh>, which is known as element <el> in
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* struct pt.
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* Example: MT_LIST_NEXT(args, struct node *, list)
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*/
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#define MT_LIST_NEXT(lh, pt, el) (MT_LIST_ELEM((lh)->next, pt, el))
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/* returns a pointer of type <pt> to a structure preceding the element
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* which contains list head <lh>, which is known as element <el> in
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* struct pt.
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*/
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#undef MT_LIST_PREV
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#define MT_LIST_PREV(lh, pt, el) (MT_LIST_ELEM((lh)->prev, pt, el))
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/* checks if the list element <el> was added to a list or not. This only
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* works when detached elements are reinitialized (using LIST_DEL_INIT)
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*/
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#define MT_LIST_ADDED(el) ((el)->next != (el))
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#endif /* _COMMON_MINI_CLIST_H */
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