54e7377035
list_replace() is similar to list_replace_rcu(), but unlike list_replace_rcu() it could be used when list_empty(old) == 1 doesn't use barriers Signed-off-by: Oleg Nesterov <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
864 lines
26 KiB
C
864 lines
26 KiB
C
#ifndef _LINUX_LIST_H
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#define _LINUX_LIST_H
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#ifdef __KERNEL__
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#include <linux/stddef.h>
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#include <linux/prefetch.h>
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#include <asm/system.h>
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/*
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* These are non-NULL pointers that will result in page faults
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* under normal circumstances, used to verify that nobody uses
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* non-initialized list entries.
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*/
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#define LIST_POISON1 ((void *) 0x00100100)
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#define LIST_POISON2 ((void *) 0x00200200)
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/*
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* Simple doubly linked list implementation.
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*
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* Some of the internal functions ("__xxx") are useful when
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* manipulating whole lists rather than single entries, as
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* sometimes we already know the next/prev entries and we can
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* generate better code by using them directly rather than
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* using the generic single-entry routines.
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*/
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struct list_head {
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struct list_head *next, *prev;
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};
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#define LIST_HEAD_INIT(name) { &(name), &(name) }
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#define LIST_HEAD(name) \
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struct list_head name = LIST_HEAD_INIT(name)
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static inline void INIT_LIST_HEAD(struct list_head *list)
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{
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list->next = list;
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list->prev = list;
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}
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/*
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* Insert a new entry between two known consecutive entries.
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*
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* This is only for internal list manipulation where we know
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* the prev/next entries already!
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*/
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static inline void __list_add(struct list_head *new,
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struct list_head *prev,
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struct list_head *next)
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{
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next->prev = new;
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new->next = next;
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new->prev = prev;
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prev->next = new;
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}
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/**
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* list_add - add a new entry
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* @new: new entry to be added
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* @head: list head to add it after
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*
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* Insert a new entry after the specified head.
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* This is good for implementing stacks.
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*/
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static inline void list_add(struct list_head *new, struct list_head *head)
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{
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__list_add(new, head, head->next);
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}
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/**
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* list_add_tail - add a new entry
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* @new: new entry to be added
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* @head: list head to add it before
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*
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* Insert a new entry before the specified head.
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* This is useful for implementing queues.
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*/
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static inline void list_add_tail(struct list_head *new, struct list_head *head)
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{
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__list_add(new, head->prev, head);
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}
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/*
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* Insert a new entry between two known consecutive entries.
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*
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* This is only for internal list manipulation where we know
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* the prev/next entries already!
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*/
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static inline void __list_add_rcu(struct list_head * new,
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struct list_head * prev, struct list_head * next)
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{
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new->next = next;
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new->prev = prev;
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smp_wmb();
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next->prev = new;
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prev->next = new;
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}
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/**
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* list_add_rcu - add a new entry to rcu-protected list
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* @new: new entry to be added
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* @head: list head to add it after
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*
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* Insert a new entry after the specified head.
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* This is good for implementing stacks.
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*
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* The caller must take whatever precautions are necessary
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* (such as holding appropriate locks) to avoid racing
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* with another list-mutation primitive, such as list_add_rcu()
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* or list_del_rcu(), running on this same list.
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* However, it is perfectly legal to run concurrently with
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* the _rcu list-traversal primitives, such as
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* list_for_each_entry_rcu().
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*/
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static inline void list_add_rcu(struct list_head *new, struct list_head *head)
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{
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__list_add_rcu(new, head, head->next);
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}
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/**
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* list_add_tail_rcu - add a new entry to rcu-protected list
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* @new: new entry to be added
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* @head: list head to add it before
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*
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* Insert a new entry before the specified head.
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* This is useful for implementing queues.
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*
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* The caller must take whatever precautions are necessary
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* (such as holding appropriate locks) to avoid racing
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* with another list-mutation primitive, such as list_add_tail_rcu()
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* or list_del_rcu(), running on this same list.
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* However, it is perfectly legal to run concurrently with
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* the _rcu list-traversal primitives, such as
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* list_for_each_entry_rcu().
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*/
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static inline void list_add_tail_rcu(struct list_head *new,
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struct list_head *head)
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{
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__list_add_rcu(new, head->prev, head);
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}
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/*
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* Delete a list entry by making the prev/next entries
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* point to each other.
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*
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* This is only for internal list manipulation where we know
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* the prev/next entries already!
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*/
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static inline void __list_del(struct list_head * prev, struct list_head * next)
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{
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next->prev = prev;
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prev->next = next;
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}
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/**
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* list_del - deletes entry from list.
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* @entry: the element to delete from the list.
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* Note: list_empty on entry does not return true after this, the entry is
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* in an undefined state.
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*/
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static inline void list_del(struct list_head *entry)
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{
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__list_del(entry->prev, entry->next);
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entry->next = LIST_POISON1;
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entry->prev = LIST_POISON2;
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}
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/**
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* list_del_rcu - deletes entry from list without re-initialization
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* @entry: the element to delete from the list.
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*
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* Note: list_empty on entry does not return true after this,
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* the entry is in an undefined state. It is useful for RCU based
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* lockfree traversal.
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*
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* In particular, it means that we can not poison the forward
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* pointers that may still be used for walking the list.
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*
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* The caller must take whatever precautions are necessary
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* (such as holding appropriate locks) to avoid racing
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* with another list-mutation primitive, such as list_del_rcu()
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* or list_add_rcu(), running on this same list.
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* However, it is perfectly legal to run concurrently with
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* the _rcu list-traversal primitives, such as
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* list_for_each_entry_rcu().
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*
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* Note that the caller is not permitted to immediately free
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* the newly deleted entry. Instead, either synchronize_rcu()
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* or call_rcu() must be used to defer freeing until an RCU
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* grace period has elapsed.
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*/
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static inline void list_del_rcu(struct list_head *entry)
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{
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__list_del(entry->prev, entry->next);
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entry->prev = LIST_POISON2;
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}
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/**
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* list_replace - replace old entry by new one
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* @old : the element to be replaced
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* @new : the new element to insert
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* Note: if 'old' was empty, it will be overwritten.
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*/
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static inline void list_replace(struct list_head *old,
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struct list_head *new)
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{
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new->next = old->next;
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new->next->prev = new;
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new->prev = old->prev;
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new->prev->next = new;
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}
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static inline void list_replace_init(struct list_head *old,
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struct list_head *new)
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{
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list_replace(old, new);
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INIT_LIST_HEAD(old);
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}
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/*
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* list_replace_rcu - replace old entry by new one
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* @old : the element to be replaced
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* @new : the new element to insert
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*
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* The old entry will be replaced with the new entry atomically.
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* Note: 'old' should not be empty.
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*/
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static inline void list_replace_rcu(struct list_head *old,
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struct list_head *new)
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{
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new->next = old->next;
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new->prev = old->prev;
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smp_wmb();
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new->next->prev = new;
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new->prev->next = new;
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old->prev = LIST_POISON2;
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}
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/**
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* list_del_init - deletes entry from list and reinitialize it.
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* @entry: the element to delete from the list.
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*/
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static inline void list_del_init(struct list_head *entry)
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{
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__list_del(entry->prev, entry->next);
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INIT_LIST_HEAD(entry);
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}
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/**
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* list_move - delete from one list and add as another's head
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* @list: the entry to move
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* @head: the head that will precede our entry
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*/
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static inline void list_move(struct list_head *list, struct list_head *head)
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{
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__list_del(list->prev, list->next);
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list_add(list, head);
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}
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/**
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* list_move_tail - delete from one list and add as another's tail
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* @list: the entry to move
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* @head: the head that will follow our entry
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*/
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static inline void list_move_tail(struct list_head *list,
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struct list_head *head)
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{
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__list_del(list->prev, list->next);
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list_add_tail(list, head);
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}
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/**
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* list_empty - tests whether a list is empty
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* @head: the list to test.
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*/
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static inline int list_empty(const struct list_head *head)
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{
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return head->next == head;
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}
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/**
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* list_empty_careful - tests whether a list is
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* empty _and_ checks that no other CPU might be
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* in the process of still modifying either member
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*
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* NOTE: using list_empty_careful() without synchronization
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* can only be safe if the only activity that can happen
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* to the list entry is list_del_init(). Eg. it cannot be used
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* if another CPU could re-list_add() it.
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*
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* @head: the list to test.
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*/
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static inline int list_empty_careful(const struct list_head *head)
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{
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struct list_head *next = head->next;
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return (next == head) && (next == head->prev);
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}
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static inline void __list_splice(struct list_head *list,
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struct list_head *head)
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{
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struct list_head *first = list->next;
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struct list_head *last = list->prev;
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struct list_head *at = head->next;
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first->prev = head;
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head->next = first;
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last->next = at;
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at->prev = last;
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}
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/**
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* list_splice - join two lists
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* @list: the new list to add.
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* @head: the place to add it in the first list.
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*/
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static inline void list_splice(struct list_head *list, struct list_head *head)
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{
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if (!list_empty(list))
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__list_splice(list, head);
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}
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/**
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* list_splice_init - join two lists and reinitialise the emptied list.
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* @list: the new list to add.
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* @head: the place to add it in the first list.
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*
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* The list at @list is reinitialised
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*/
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static inline void list_splice_init(struct list_head *list,
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struct list_head *head)
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{
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if (!list_empty(list)) {
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__list_splice(list, head);
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INIT_LIST_HEAD(list);
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}
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}
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/**
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* list_entry - get the struct for this entry
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* @ptr: the &struct list_head pointer.
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* @type: the type of the struct this is embedded in.
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* @member: the name of the list_struct within the struct.
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*/
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#define list_entry(ptr, type, member) \
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container_of(ptr, type, member)
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/**
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* list_for_each - iterate over a list
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* @pos: the &struct list_head to use as a loop counter.
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* @head: the head for your list.
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*/
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#define list_for_each(pos, head) \
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for (pos = (head)->next; prefetch(pos->next), pos != (head); \
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pos = pos->next)
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/**
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* __list_for_each - iterate over a list
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* @pos: the &struct list_head to use as a loop counter.
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* @head: the head for your list.
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*
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* This variant differs from list_for_each() in that it's the
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* simplest possible list iteration code, no prefetching is done.
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* Use this for code that knows the list to be very short (empty
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* or 1 entry) most of the time.
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*/
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#define __list_for_each(pos, head) \
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for (pos = (head)->next; pos != (head); pos = pos->next)
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/**
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* list_for_each_prev - iterate over a list backwards
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* @pos: the &struct list_head to use as a loop counter.
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* @head: the head for your list.
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*/
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#define list_for_each_prev(pos, head) \
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for (pos = (head)->prev; prefetch(pos->prev), pos != (head); \
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pos = pos->prev)
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/**
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* list_for_each_safe - iterate over a list safe against removal of list entry
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* @pos: the &struct list_head to use as a loop counter.
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* @n: another &struct list_head to use as temporary storage
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* @head: the head for your list.
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*/
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#define list_for_each_safe(pos, n, head) \
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for (pos = (head)->next, n = pos->next; pos != (head); \
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pos = n, n = pos->next)
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/**
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* list_for_each_entry - iterate over list of given type
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* @pos: the type * to use as a loop counter.
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* @head: the head for your list.
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* @member: the name of the list_struct within the struct.
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*/
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#define list_for_each_entry(pos, head, member) \
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for (pos = list_entry((head)->next, typeof(*pos), member); \
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prefetch(pos->member.next), &pos->member != (head); \
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pos = list_entry(pos->member.next, typeof(*pos), member))
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/**
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* list_for_each_entry_reverse - iterate backwards over list of given type.
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* @pos: the type * to use as a loop counter.
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* @head: the head for your list.
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* @member: the name of the list_struct within the struct.
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*/
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#define list_for_each_entry_reverse(pos, head, member) \
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for (pos = list_entry((head)->prev, typeof(*pos), member); \
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prefetch(pos->member.prev), &pos->member != (head); \
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pos = list_entry(pos->member.prev, typeof(*pos), member))
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/**
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* list_prepare_entry - prepare a pos entry for use as a start point in
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* list_for_each_entry_continue
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* @pos: the type * to use as a start point
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* @head: the head of the list
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* @member: the name of the list_struct within the struct.
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*/
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#define list_prepare_entry(pos, head, member) \
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((pos) ? : list_entry(head, typeof(*pos), member))
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/**
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* list_for_each_entry_continue - iterate over list of given type
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* continuing after existing point
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* @pos: the type * to use as a loop counter.
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* @head: the head for your list.
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* @member: the name of the list_struct within the struct.
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*/
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#define list_for_each_entry_continue(pos, head, member) \
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for (pos = list_entry(pos->member.next, typeof(*pos), member); \
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prefetch(pos->member.next), &pos->member != (head); \
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pos = list_entry(pos->member.next, typeof(*pos), member))
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/**
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* list_for_each_entry_from - iterate over list of given type
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* continuing from existing point
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* @pos: the type * to use as a loop counter.
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* @head: the head for your list.
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* @member: the name of the list_struct within the struct.
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*/
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#define list_for_each_entry_from(pos, head, member) \
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for (; prefetch(pos->member.next), &pos->member != (head); \
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pos = list_entry(pos->member.next, typeof(*pos), member))
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/**
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* list_for_each_entry_safe - iterate over list of given type safe against removal of list entry
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* @pos: the type * to use as a loop counter.
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* @n: another type * to use as temporary storage
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* @head: the head for your list.
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* @member: the name of the list_struct within the struct.
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*/
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#define list_for_each_entry_safe(pos, n, head, member) \
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for (pos = list_entry((head)->next, typeof(*pos), member), \
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n = list_entry(pos->member.next, typeof(*pos), member); \
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&pos->member != (head); \
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pos = n, n = list_entry(n->member.next, typeof(*n), member))
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/**
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* list_for_each_entry_safe_continue - iterate over list of given type
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* continuing after existing point safe against removal of list entry
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* @pos: the type * to use as a loop counter.
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* @n: another type * to use as temporary storage
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* @head: the head for your list.
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* @member: the name of the list_struct within the struct.
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*/
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#define list_for_each_entry_safe_continue(pos, n, head, member) \
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for (pos = list_entry(pos->member.next, typeof(*pos), member), \
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n = list_entry(pos->member.next, typeof(*pos), member); \
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&pos->member != (head); \
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pos = n, n = list_entry(n->member.next, typeof(*n), member))
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/**
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* list_for_each_entry_safe_from - iterate over list of given type
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* from existing point safe against removal of list entry
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* @pos: the type * to use as a loop counter.
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* @n: another type * to use as temporary storage
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* @head: the head for your list.
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* @member: the name of the list_struct within the struct.
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*/
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#define list_for_each_entry_safe_from(pos, n, head, member) \
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for (n = list_entry(pos->member.next, typeof(*pos), member); \
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&pos->member != (head); \
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pos = n, n = list_entry(n->member.next, typeof(*n), member))
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/**
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* list_for_each_entry_safe_reverse - iterate backwards over list of given type safe against
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* removal of list entry
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* @pos: the type * to use as a loop counter.
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* @n: another type * to use as temporary storage
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* @head: the head for your list.
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* @member: the name of the list_struct within the struct.
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*/
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#define list_for_each_entry_safe_reverse(pos, n, head, member) \
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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))
|
|
|
|
/**
|
|
* list_for_each_rcu - iterate over an rcu-protected list
|
|
* @pos: the &struct list_head to use as a loop counter.
|
|
* @head: the head for your list.
|
|
*
|
|
* This list-traversal primitive may safely run concurrently with
|
|
* the _rcu list-mutation primitives such as list_add_rcu()
|
|
* as long as the traversal is guarded by rcu_read_lock().
|
|
*/
|
|
#define list_for_each_rcu(pos, head) \
|
|
for (pos = (head)->next; \
|
|
prefetch(rcu_dereference(pos)->next), pos != (head); \
|
|
pos = pos->next)
|
|
|
|
#define __list_for_each_rcu(pos, head) \
|
|
for (pos = (head)->next; \
|
|
rcu_dereference(pos) != (head); \
|
|
pos = pos->next)
|
|
|
|
/**
|
|
* list_for_each_safe_rcu - iterate over an rcu-protected list safe
|
|
* against removal of list entry
|
|
* @pos: the &struct list_head to use as a loop counter.
|
|
* @n: another &struct list_head to use as temporary storage
|
|
* @head: the head for your list.
|
|
*
|
|
* This list-traversal primitive may safely run concurrently with
|
|
* the _rcu list-mutation primitives such as list_add_rcu()
|
|
* as long as the traversal is guarded by rcu_read_lock().
|
|
*/
|
|
#define list_for_each_safe_rcu(pos, n, head) \
|
|
for (pos = (head)->next; \
|
|
n = rcu_dereference(pos)->next, pos != (head); \
|
|
pos = n)
|
|
|
|
/**
|
|
* list_for_each_entry_rcu - iterate over rcu list of given type
|
|
* @pos: the type * to use as a loop counter.
|
|
* @head: the head for your list.
|
|
* @member: the name of the list_struct within the struct.
|
|
*
|
|
* This list-traversal primitive may safely run concurrently with
|
|
* the _rcu list-mutation primitives such as list_add_rcu()
|
|
* as long as the traversal is guarded by rcu_read_lock().
|
|
*/
|
|
#define list_for_each_entry_rcu(pos, head, member) \
|
|
for (pos = list_entry((head)->next, typeof(*pos), member); \
|
|
prefetch(rcu_dereference(pos)->member.next), \
|
|
&pos->member != (head); \
|
|
pos = list_entry(pos->member.next, typeof(*pos), member))
|
|
|
|
|
|
/**
|
|
* list_for_each_continue_rcu - iterate over an rcu-protected list
|
|
* continuing after existing point.
|
|
* @pos: the &struct list_head to use as a loop counter.
|
|
* @head: the head for your list.
|
|
*
|
|
* This list-traversal primitive may safely run concurrently with
|
|
* the _rcu list-mutation primitives such as list_add_rcu()
|
|
* as long as the traversal is guarded by rcu_read_lock().
|
|
*/
|
|
#define list_for_each_continue_rcu(pos, head) \
|
|
for ((pos) = (pos)->next; \
|
|
prefetch(rcu_dereference((pos))->next), (pos) != (head); \
|
|
(pos) = (pos)->next)
|
|
|
|
/*
|
|
* Double linked lists with a single pointer list head.
|
|
* Mostly useful for hash tables where the two pointer list head is
|
|
* too wasteful.
|
|
* You lose the ability to access the tail in O(1).
|
|
*/
|
|
|
|
struct hlist_head {
|
|
struct hlist_node *first;
|
|
};
|
|
|
|
struct hlist_node {
|
|
struct hlist_node *next, **pprev;
|
|
};
|
|
|
|
#define HLIST_HEAD_INIT { .first = NULL }
|
|
#define HLIST_HEAD(name) struct hlist_head name = { .first = NULL }
|
|
#define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL)
|
|
static inline void INIT_HLIST_NODE(struct hlist_node *h)
|
|
{
|
|
h->next = NULL;
|
|
h->pprev = NULL;
|
|
}
|
|
|
|
static inline int hlist_unhashed(const struct hlist_node *h)
|
|
{
|
|
return !h->pprev;
|
|
}
|
|
|
|
static inline int hlist_empty(const struct hlist_head *h)
|
|
{
|
|
return !h->first;
|
|
}
|
|
|
|
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;
|
|
}
|
|
|
|
static inline void hlist_del(struct hlist_node *n)
|
|
{
|
|
__hlist_del(n);
|
|
n->next = LIST_POISON1;
|
|
n->pprev = LIST_POISON2;
|
|
}
|
|
|
|
/**
|
|
* hlist_del_rcu - deletes entry from hash list without re-initialization
|
|
* @n: the element to delete from the hash list.
|
|
*
|
|
* Note: list_unhashed() on entry does not return true after this,
|
|
* the entry is in an undefined state. It is useful for RCU based
|
|
* lockfree traversal.
|
|
*
|
|
* In particular, it means that we can not poison the forward
|
|
* pointers that may still be used for walking the hash list.
|
|
*
|
|
* The caller must take whatever precautions are necessary
|
|
* (such as holding appropriate locks) to avoid racing
|
|
* with another list-mutation primitive, such as hlist_add_head_rcu()
|
|
* or hlist_del_rcu(), running on this same list.
|
|
* However, it is perfectly legal to run concurrently with
|
|
* the _rcu list-traversal primitives, such as
|
|
* hlist_for_each_entry().
|
|
*/
|
|
static inline void hlist_del_rcu(struct hlist_node *n)
|
|
{
|
|
__hlist_del(n);
|
|
n->pprev = LIST_POISON2;
|
|
}
|
|
|
|
static inline void hlist_del_init(struct hlist_node *n)
|
|
{
|
|
if (!hlist_unhashed(n)) {
|
|
__hlist_del(n);
|
|
INIT_HLIST_NODE(n);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* hlist_replace_rcu - replace old entry by new one
|
|
* @old : the element to be replaced
|
|
* @new : the new element to insert
|
|
*
|
|
* The old entry will be replaced with the new entry atomically.
|
|
*/
|
|
static inline void hlist_replace_rcu(struct hlist_node *old,
|
|
struct hlist_node *new)
|
|
{
|
|
struct hlist_node *next = old->next;
|
|
|
|
new->next = next;
|
|
new->pprev = old->pprev;
|
|
smp_wmb();
|
|
if (next)
|
|
new->next->pprev = &new->next;
|
|
*new->pprev = new;
|
|
old->pprev = LIST_POISON2;
|
|
}
|
|
|
|
static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
|
|
{
|
|
struct hlist_node *first = h->first;
|
|
n->next = first;
|
|
if (first)
|
|
first->pprev = &n->next;
|
|
h->first = n;
|
|
n->pprev = &h->first;
|
|
}
|
|
|
|
|
|
/**
|
|
* hlist_add_head_rcu - adds the specified element to the specified hlist,
|
|
* while permitting racing traversals.
|
|
* @n: the element to add to the hash list.
|
|
* @h: the list to add to.
|
|
*
|
|
* The caller must take whatever precautions are necessary
|
|
* (such as holding appropriate locks) to avoid racing
|
|
* with another list-mutation primitive, such as hlist_add_head_rcu()
|
|
* or hlist_del_rcu(), running on this same list.
|
|
* However, it is perfectly legal to run concurrently with
|
|
* the _rcu list-traversal primitives, such as
|
|
* hlist_for_each_entry_rcu(), used to prevent memory-consistency
|
|
* problems on Alpha CPUs. Regardless of the type of CPU, the
|
|
* list-traversal primitive must be guarded by rcu_read_lock().
|
|
*/
|
|
static inline void hlist_add_head_rcu(struct hlist_node *n,
|
|
struct hlist_head *h)
|
|
{
|
|
struct hlist_node *first = h->first;
|
|
n->next = first;
|
|
n->pprev = &h->first;
|
|
smp_wmb();
|
|
if (first)
|
|
first->pprev = &n->next;
|
|
h->first = n;
|
|
}
|
|
|
|
/* next must be != NULL */
|
|
static inline void hlist_add_before(struct hlist_node *n,
|
|
struct hlist_node *next)
|
|
{
|
|
n->pprev = next->pprev;
|
|
n->next = next;
|
|
next->pprev = &n->next;
|
|
*(n->pprev) = n;
|
|
}
|
|
|
|
static inline void hlist_add_after(struct hlist_node *n,
|
|
struct hlist_node *next)
|
|
{
|
|
next->next = n->next;
|
|
n->next = next;
|
|
next->pprev = &n->next;
|
|
|
|
if(next->next)
|
|
next->next->pprev = &next->next;
|
|
}
|
|
|
|
/**
|
|
* hlist_add_before_rcu - adds the specified element to the specified hlist
|
|
* before the specified node while permitting racing traversals.
|
|
* @n: the new element to add to the hash list.
|
|
* @next: the existing element to add the new element before.
|
|
*
|
|
* The caller must take whatever precautions are necessary
|
|
* (such as holding appropriate locks) to avoid racing
|
|
* with another list-mutation primitive, such as hlist_add_head_rcu()
|
|
* or hlist_del_rcu(), running on this same list.
|
|
* However, it is perfectly legal to run concurrently with
|
|
* the _rcu list-traversal primitives, such as
|
|
* hlist_for_each_entry_rcu(), used to prevent memory-consistency
|
|
* problems on Alpha CPUs.
|
|
*/
|
|
static inline void hlist_add_before_rcu(struct hlist_node *n,
|
|
struct hlist_node *next)
|
|
{
|
|
n->pprev = next->pprev;
|
|
n->next = next;
|
|
smp_wmb();
|
|
next->pprev = &n->next;
|
|
*(n->pprev) = n;
|
|
}
|
|
|
|
/**
|
|
* hlist_add_after_rcu - adds the specified element to the specified hlist
|
|
* after the specified node while permitting racing traversals.
|
|
* @prev: the existing element to add the new element after.
|
|
* @n: the new element to add to the hash list.
|
|
*
|
|
* The caller must take whatever precautions are necessary
|
|
* (such as holding appropriate locks) to avoid racing
|
|
* with another list-mutation primitive, such as hlist_add_head_rcu()
|
|
* or hlist_del_rcu(), running on this same list.
|
|
* However, it is perfectly legal to run concurrently with
|
|
* the _rcu list-traversal primitives, such as
|
|
* hlist_for_each_entry_rcu(), used to prevent memory-consistency
|
|
* problems on Alpha CPUs.
|
|
*/
|
|
static inline void hlist_add_after_rcu(struct hlist_node *prev,
|
|
struct hlist_node *n)
|
|
{
|
|
n->next = prev->next;
|
|
n->pprev = &prev->next;
|
|
smp_wmb();
|
|
prev->next = n;
|
|
if (n->next)
|
|
n->next->pprev = &n->next;
|
|
}
|
|
|
|
#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)
|
|
|
|
#define hlist_for_each_safe(pos, n, head) \
|
|
for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \
|
|
pos = n)
|
|
|
|
/**
|
|
* hlist_for_each_entry - iterate over list of given type
|
|
* @tpos: the type * to use as a loop counter.
|
|
* @pos: the &struct hlist_node to use as a loop counter.
|
|
* @head: the head for your list.
|
|
* @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)
|
|
|
|
/**
|
|
* hlist_for_each_entry_continue - iterate over a hlist continuing after existing point
|
|
* @tpos: the type * to use as a loop counter.
|
|
* @pos: the &struct hlist_node to use as a loop counter.
|
|
* @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)
|
|
|
|
/**
|
|
* hlist_for_each_entry_from - iterate over a hlist continuing from existing point
|
|
* @tpos: the type * to use as a loop counter.
|
|
* @pos: the &struct hlist_node to use as a loop counter.
|
|
* @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)
|
|
|
|
/**
|
|
* hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry
|
|
* @tpos: the type * to use as a loop counter.
|
|
* @pos: the &struct hlist_node to use as a loop counter.
|
|
* @n: another &struct hlist_node to use as temporary storage
|
|
* @head: the head for your list.
|
|
* @member: the name of the hlist_node within the struct.
|
|
*/
|
|
#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)
|
|
|
|
/**
|
|
* hlist_for_each_entry_rcu - iterate over rcu list of given type
|
|
* @tpos: the type * to use as a loop counter.
|
|
* @pos: the &struct hlist_node to use as a loop counter.
|
|
* @head: the head for your list.
|
|
* @member: the name of the hlist_node within the struct.
|
|
*
|
|
* This list-traversal primitive may safely run concurrently with
|
|
* the _rcu list-mutation primitives such as hlist_add_head_rcu()
|
|
* as long as the traversal is guarded by rcu_read_lock().
|
|
*/
|
|
#define hlist_for_each_entry_rcu(tpos, pos, head, member) \
|
|
for (pos = (head)->first; \
|
|
rcu_dereference(pos) && ({ prefetch(pos->next); 1;}) && \
|
|
({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
|
|
pos = pos->next)
|
|
|
|
#else
|
|
#warning "don't include kernel headers in userspace"
|
|
#endif /* __KERNEL__ */
|
|
#endif
|