Ben Pfaff
726bd68327
There is no need for a "safe" version of the RCU list iteration macros, because the ordinary version of the macros is "safe". Linux 2.6.26-rc1 removed these "safe" versions, so this change modifies OpenFlow's uses of these macros to use the ordinary versions. This also simplifies the code because we don't need to use the list_entry macros any longer.
494 lines
15 KiB
C
494 lines
15 KiB
C
#ifndef __LINUX_LIST_WRAPPER_H
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#define __LINUX_LIST_WRAPPER_H
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#ifdef __KERNEL__
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#include_next <linux/list.h>
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#include <asm/system.h>
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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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* 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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* 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_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_for_each_rcu - iterate over an rcu-protected list
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* @pos: the &struct list_head to use as a loop cursor.
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* @head: the head for your list.
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*
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* This list-traversal primitive may safely run concurrently with
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* the _rcu list-mutation primitives such as list_add_rcu()
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* as long as the traversal is guarded by rcu_read_lock().
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*/
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#define list_for_each_rcu(pos, head) \
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for (pos = (head)->next; \
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prefetch(rcu_dereference(pos)->next), pos != (head); \
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pos = pos->next)
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#define __list_for_each_rcu(pos, head) \
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for (pos = (head)->next; \
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rcu_dereference(pos) != (head); \
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pos = pos->next)
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/**
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* list_for_each_entry_rcu - iterate over rcu list of given type
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* @pos: the type * to use as a loop cursor.
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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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* This list-traversal primitive may safely run concurrently with
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* the _rcu list-mutation primitives such as list_add_rcu()
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* as long as the traversal is guarded by rcu_read_lock().
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*/
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#define list_for_each_entry_rcu(pos, head, member) \
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for (pos = list_entry((head)->next, typeof(*pos), member); \
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prefetch(rcu_dereference(pos)->member.next), \
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&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_continue_rcu
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* @pos: the &struct list_head to use as a loop cursor.
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* @head: the head for your list.
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*
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* Iterate over an rcu-protected list, continuing after current point.
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*
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* This list-traversal primitive may safely run concurrently with
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* the _rcu list-mutation primitives such as list_add_rcu()
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* as long as the traversal is guarded by rcu_read_lock().
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*/
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#define list_for_each_continue_rcu(pos, head) \
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for ((pos) = (pos)->next; \
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prefetch(rcu_dereference((pos))->next), (pos) != (head); \
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(pos) = (pos)->next)
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/*
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* Double linked lists with a single pointer list head.
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* Mostly useful for hash tables where the two pointer list head is
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* too wasteful.
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* You lose the ability to access the tail in O(1).
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*/
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struct hlist_head {
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struct hlist_node *first;
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};
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struct hlist_node {
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struct hlist_node *next, **pprev;
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};
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#define HLIST_HEAD_INIT { .first = NULL }
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#define HLIST_HEAD(name) struct hlist_head name = { .first = NULL }
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#define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL)
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static inline void INIT_HLIST_NODE(struct hlist_node *h)
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{
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h->next = NULL;
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h->pprev = NULL;
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}
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static inline int hlist_unhashed(const struct hlist_node *h)
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{
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return !h->pprev;
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}
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static inline int hlist_empty(const struct hlist_head *h)
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{
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return !h->first;
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}
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static inline void __hlist_del(struct hlist_node *n)
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{
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struct hlist_node *next = n->next;
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struct hlist_node **pprev = n->pprev;
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*pprev = next;
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if (next)
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next->pprev = pprev;
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}
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static inline void hlist_del(struct hlist_node *n)
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{
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__hlist_del(n);
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n->next = LIST_POISON1;
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n->pprev = LIST_POISON2;
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}
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/**
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* hlist_del_rcu - deletes entry from hash list without re-initialization
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* @n: the element to delete from the hash list.
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*
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* Note: list_unhashed() 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 hash 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 hlist_add_head_rcu()
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* or hlist_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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* hlist_for_each_entry().
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*/
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static inline void hlist_del_rcu(struct hlist_node *n)
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{
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__hlist_del(n);
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n->pprev = LIST_POISON2;
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}
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static inline void hlist_del_init(struct hlist_node *n)
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{
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if (!hlist_unhashed(n)) {
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__hlist_del(n);
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INIT_HLIST_NODE(n);
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}
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}
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/**
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* hlist_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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*/
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static inline void hlist_replace_rcu(struct hlist_node *old,
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struct hlist_node *new)
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{
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struct hlist_node *next = old->next;
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new->next = next;
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new->pprev = old->pprev;
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smp_wmb();
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if (next)
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new->next->pprev = &new->next;
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*new->pprev = new;
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old->pprev = LIST_POISON2;
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}
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static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
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{
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struct hlist_node *first = h->first;
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n->next = first;
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if (first)
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first->pprev = &n->next;
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h->first = n;
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n->pprev = &h->first;
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}
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/**
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* hlist_add_head_rcu
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* @n: the element to add to the hash list.
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* @h: the list to add to.
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*
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* Description:
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* Adds the specified element to the specified hlist,
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* while permitting racing traversals.
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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 hlist_add_head_rcu()
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* or hlist_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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* hlist_for_each_entry_rcu(), used to prevent memory-consistency
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* problems on Alpha CPUs. Regardless of the type of CPU, the
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* list-traversal primitive must be guarded by rcu_read_lock().
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*/
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static inline void hlist_add_head_rcu(struct hlist_node *n,
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struct hlist_head *h)
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{
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struct hlist_node *first = h->first;
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n->next = first;
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n->pprev = &h->first;
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smp_wmb();
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if (first)
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first->pprev = &n->next;
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h->first = n;
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}
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/* next must be != NULL */
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static inline void hlist_add_before(struct hlist_node *n,
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struct hlist_node *next)
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{
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n->pprev = next->pprev;
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n->next = next;
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next->pprev = &n->next;
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*(n->pprev) = n;
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}
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static inline void hlist_add_after(struct hlist_node *n,
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struct hlist_node *next)
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{
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next->next = n->next;
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n->next = next;
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next->pprev = &n->next;
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if(next->next)
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next->next->pprev = &next->next;
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}
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/**
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* hlist_add_before_rcu
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* @n: the new element to add to the hash list.
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* @next: the existing element to add the new element before.
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*
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* Description:
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* Adds the specified element to the specified hlist
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* before the specified node while permitting racing traversals.
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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 hlist_add_head_rcu()
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* or hlist_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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* hlist_for_each_entry_rcu(), used to prevent memory-consistency
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* problems on Alpha CPUs.
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*/
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static inline void hlist_add_before_rcu(struct hlist_node *n,
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struct hlist_node *next)
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{
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n->pprev = next->pprev;
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n->next = next;
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smp_wmb();
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next->pprev = &n->next;
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*(n->pprev) = n;
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}
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/**
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* hlist_add_after_rcu
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* @prev: the existing element to add the new element after.
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* @n: the new element to add to the hash list.
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*
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* Description:
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* Adds the specified element to the specified hlist
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* after the specified node while permitting racing traversals.
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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 hlist_add_head_rcu()
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* or hlist_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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* hlist_for_each_entry_rcu(), used to prevent memory-consistency
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* problems on Alpha CPUs.
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*/
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static inline void hlist_add_after_rcu(struct hlist_node *prev,
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struct hlist_node *n)
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{
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n->next = prev->next;
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n->pprev = &prev->next;
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smp_wmb();
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prev->next = n;
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if (n->next)
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n->next->pprev = &n->next;
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}
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#define hlist_entry(ptr, type, member) container_of(ptr,type,member)
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#define hlist_for_each(pos, head) \
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for (pos = (head)->first; pos && ({ prefetch(pos->next); 1; }); \
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pos = pos->next)
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#define hlist_for_each_safe(pos, n, head) \
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for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \
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pos = n)
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/**
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* hlist_for_each_entry - iterate over list of given type
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* @tpos: the type * to use as a loop cursor.
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* @pos: the &struct hlist_node to use as a loop cursor.
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* @head: the head for your list.
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* @member: the name of the hlist_node within the struct.
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*/
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#define hlist_for_each_entry(tpos, pos, head, member) \
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for (pos = (head)->first; \
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pos && ({ prefetch(pos->next); 1;}) && \
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({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
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pos = pos->next)
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/**
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* hlist_for_each_entry_continue - iterate over a hlist continuing after current point
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* @tpos: the type * to use as a loop cursor.
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* @pos: the &struct hlist_node to use as a loop cursor.
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* @member: the name of the hlist_node within the struct.
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*/
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#define hlist_for_each_entry_continue(tpos, pos, member) \
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for (pos = (pos)->next; \
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pos && ({ prefetch(pos->next); 1;}) && \
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({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
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pos = pos->next)
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/**
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* hlist_for_each_entry_from - iterate over a hlist continuing from current point
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* @tpos: the type * to use as a loop cursor.
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* @pos: the &struct hlist_node to use as a loop cursor.
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* @member: the name of the hlist_node within the struct.
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*/
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#define hlist_for_each_entry_from(tpos, pos, member) \
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for (; pos && ({ prefetch(pos->next); 1;}) && \
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({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
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pos = pos->next)
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/**
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* hlist_for_each_entry_safe - iterate over list of given type safe against removal of list entry
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* @tpos: the type * to use as a loop cursor.
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* @pos: the &struct hlist_node to use as a loop cursor.
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* @n: another &struct hlist_node to use as temporary storage
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* @head: the head for your list.
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* @member: the name of the hlist_node within the struct.
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*/
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#define hlist_for_each_entry_safe(tpos, pos, n, head, member) \
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for (pos = (head)->first; \
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pos && ({ n = pos->next; 1; }) && \
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({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
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pos = n)
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/**
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* hlist_for_each_entry_rcu - iterate over rcu list of given type
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* @tpos: the type * to use as a loop cursor.
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* @pos: the &struct hlist_node to use as a loop cursor.
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* @head: the head for your list.
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* @member: the name of the hlist_node within the struct.
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*
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* This list-traversal primitive may safely run concurrently with
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* the _rcu list-mutation primitives such as hlist_add_head_rcu()
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* as long as the traversal is guarded by rcu_read_lock().
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*/
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#define hlist_for_each_entry_rcu(tpos, pos, head, member) \
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for (pos = (head)->first; \
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rcu_dereference(pos) && ({ prefetch(pos->next); 1;}) && \
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({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
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pos = pos->next)
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#if LINUX_VERSION_CODE < KERNEL_VERSION(2,4,23)
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/**
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* list_for_each_entry_safe - iterate over list of given type safe against remov
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al 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.
|
|
* @member: the name of the list_struct within the struct.
|
|
*/
|
|
#define list_for_each_entry_safe(pos, n, head, member) \
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|
for (pos = list_entry((head)->next, typeof(*pos), member), \
|
|
n = list_entry(pos->member.next, typeof(*pos), member); \
|
|
&pos->member != (head); \
|
|
pos = n, n = list_entry(n->member.next, typeof(*n), member))
|
|
#endif /* linux kernel < 2.4.23 */
|
|
|
|
|
|
#else
|
|
#warning "don't include kernel headers in userspace"
|
|
#endif /* __KERNEL__ */
|
|
#endif
|