rcu: split list.h and move rcu-protected lists into rculist.h

Move rcu-protected lists from list.h into a new header file rculist.h.

This is done because list are a very used primitive structure all over the
kernel and it's currently impossible to include other header files in this
list.h without creating some circular dependencies.

For example, list.h implements rcu-protected list and uses rcu_dereference()
without including rcupdate.h.  It actually compiles because users of
rcu_dereference() are macros.  Others RCU functions could be used too but
aren't probably because of this.

Therefore this patch creates rculist.h which includes rcupdates without to
many changes/troubles.

Signed-off-by: Franck Bui-Huu <fbuihuu@gmail.com>
Acked-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Acked-by: Josh Triplett <josh@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Franck Bui-Huu 2008-05-12 21:21:05 +02:00 коммит произвёл Ingo Molnar
Родитель 32300751b4
Коммит 82524746c2
15 изменённых файлов: 409 добавлений и 372 удалений

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@ -11,6 +11,7 @@
#include <linux/irq.h>
#include <linux/spinlock.h>
#include <linux/init.h>
#include <linux/rculist.h>
#include <asm/sn/addrs.h>
#include <asm/sn/arch.h>
#include <asm/sn/intr.h>

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@ -23,6 +23,7 @@
* 51 Franklin St - Fifth Floor, Boston, MA 02110-1301 USA.
*
*/
#include <linux/rculist.h>
#include <linux/kernel.h>
#include <linux/async_tx.h>

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@ -35,6 +35,7 @@
#include <rdma/ib_user_verbs.h>
#include <linux/io.h>
#include <linux/utsname.h>
#include <linux/rculist.h>
#include "ipath_kernel.h"
#include "ipath_verbs.h"

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@ -31,8 +31,7 @@
* SOFTWARE.
*/
#include <linux/list.h>
#include <linux/rcupdate.h>
#include <linux/rculist.h>
#include "ipath_verbs.h"

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@ -20,7 +20,7 @@
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/list.h>
#include <linux/rculist.h>
#include <linux/notifier.h>
#include <linux/netdevice.h>
#include <linux/etherdevice.h>

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@ -3,6 +3,7 @@
#include <asm/atomic.h>
#include <linux/list.h>
#include <linux/rculist.h>
#include <linux/spinlock.h>
#include <linux/cache.h>
#include <linux/rcupdate.h>

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@ -84,65 +84,6 @@ static inline void list_add_tail(struct list_head *new, struct list_head *head)
__list_add(new, head->prev, head);
}
/*
* Insert a new entry between two known consecutive entries.
*
* This is only for internal list manipulation where we know
* the prev/next entries already!
*/
static inline void __list_add_rcu(struct list_head * new,
struct list_head * prev, struct list_head * next)
{
new->next = next;
new->prev = prev;
smp_wmb();
next->prev = new;
prev->next = new;
}
/**
* list_add_rcu - add a new entry to rcu-protected list
* @new: new entry to be added
* @head: list head to add it after
*
* Insert a new entry after the specified head.
* This is good for implementing stacks.
*
* The caller must take whatever precautions are necessary
* (such as holding appropriate locks) to avoid racing
* with another list-mutation primitive, such as list_add_rcu()
* or list_del_rcu(), running on this same list.
* However, it is perfectly legal to run concurrently with
* the _rcu list-traversal primitives, such as
* list_for_each_entry_rcu().
*/
static inline void list_add_rcu(struct list_head *new, struct list_head *head)
{
__list_add_rcu(new, head, head->next);
}
/**
* list_add_tail_rcu - add a new entry to rcu-protected list
* @new: new entry to be added
* @head: list head to add it before
*
* Insert a new entry before the specified head.
* This is useful for implementing queues.
*
* The caller must take whatever precautions are necessary
* (such as holding appropriate locks) to avoid racing
* with another list-mutation primitive, such as list_add_tail_rcu()
* or list_del_rcu(), running on this same list.
* However, it is perfectly legal to run concurrently with
* the _rcu list-traversal primitives, such as
* list_for_each_entry_rcu().
*/
static inline void list_add_tail_rcu(struct list_head *new,
struct list_head *head)
{
__list_add_rcu(new, head->prev, head);
}
/*
* Delete a list entry by making the prev/next entries
* point to each other.
@ -173,36 +114,6 @@ static inline void list_del(struct list_head *entry)
extern void list_del(struct list_head *entry);
#endif
/**
* list_del_rcu - deletes entry from list without re-initialization
* @entry: the element to delete from the list.
*
* Note: list_empty() 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 list.
*
* The caller must take whatever precautions are necessary
* (such as holding appropriate locks) to avoid racing
* with another list-mutation primitive, such as list_del_rcu()
* or list_add_rcu(), running on this same list.
* However, it is perfectly legal to run concurrently with
* the _rcu list-traversal primitives, such as
* list_for_each_entry_rcu().
*
* Note that the caller is not permitted to immediately free
* the newly deleted entry. Instead, either synchronize_rcu()
* or call_rcu() must be used to defer freeing until an RCU
* grace period has elapsed.
*/
static inline void list_del_rcu(struct list_head *entry)
{
__list_del(entry->prev, entry->next);
entry->prev = LIST_POISON2;
}
/**
* list_replace - replace old entry by new one
* @old : the element to be replaced
@ -226,25 +137,6 @@ static inline void list_replace_init(struct list_head *old,
INIT_LIST_HEAD(old);
}
/**
* list_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.
* Note: @old should not be empty.
*/
static inline void list_replace_rcu(struct list_head *old,
struct list_head *new)
{
new->next = old->next;
new->prev = old->prev;
smp_wmb();
new->next->prev = new;
new->prev->next = new;
old->prev = LIST_POISON2;
}
/**
* list_del_init - deletes entry from list and reinitialize it.
* @entry: the element to delete from the list.
@ -368,62 +260,6 @@ static inline void list_splice_init(struct list_head *list,
}
}
/**
* list_splice_init_rcu - splice an RCU-protected list into an existing list.
* @list: the RCU-protected list to splice
* @head: the place in the list to splice the first list into
* @sync: function to sync: synchronize_rcu(), synchronize_sched(), ...
*
* @head can be RCU-read traversed concurrently with this function.
*
* Note that this function blocks.
*
* Important note: the caller must take whatever action is necessary to
* prevent any other updates to @head. In principle, it is possible
* to modify the list as soon as sync() begins execution.
* If this sort of thing becomes necessary, an alternative version
* based on call_rcu() could be created. But only if -really-
* needed -- there is no shortage of RCU API members.
*/
static inline void list_splice_init_rcu(struct list_head *list,
struct list_head *head,
void (*sync)(void))
{
struct list_head *first = list->next;
struct list_head *last = list->prev;
struct list_head *at = head->next;
if (list_empty(head))
return;
/* "first" and "last" tracking list, so initialize it. */
INIT_LIST_HEAD(list);
/*
* At this point, the list body still points to the source list.
* Wait for any readers to finish using the list before splicing
* the list body into the new list. Any new readers will see
* an empty list.
*/
sync();
/*
* Readers are finished with the source list, so perform splice.
* The order is important if the new list is global and accessible
* to concurrent RCU readers. Note that RCU readers are not
* permitted to traverse the prev pointers without excluding
* this function.
*/
last->next = at;
smp_wmb();
head->next = first;
first->prev = head;
at->prev = last;
}
/**
* list_entry - get the struct for this entry
* @ptr: the &struct list_head pointer.
@ -629,57 +465,6 @@ static inline void list_splice_init_rcu(struct list_head *list,
&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 cursor.
* @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 = rcu_dereference((head)->next); \
prefetch(pos->next), pos != (head); \
pos = rcu_dereference(pos->next))
#define __list_for_each_rcu(pos, head) \
for (pos = rcu_dereference((head)->next); \
pos != (head); \
pos = rcu_dereference(pos->next))
/**
* list_for_each_entry_rcu - iterate over rcu list of given type
* @pos: the type * to use as a loop cursor.
* @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(rcu_dereference((head)->next), typeof(*pos), member); \
prefetch(pos->member.next), &pos->member != (head); \
pos = list_entry(rcu_dereference(pos->member.next), typeof(*pos), member))
/**
* list_for_each_continue_rcu
* @pos: the &struct list_head to use as a loop cursor.
* @head: the head for your list.
*
* Iterate over an rcu-protected list, continuing after current point.
*
* 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) = rcu_dereference((pos)->next); \
prefetch((pos)->next), (pos) != (head); \
(pos) = rcu_dereference((pos)->next))
/*
* Double linked lists with a single pointer list head.
* Mostly useful for hash tables where the two pointer list head is
@ -730,31 +515,6 @@ static inline void hlist_del(struct hlist_node *n)
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)) {
@ -763,27 +523,6 @@ static inline void hlist_del_init(struct 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;
@ -794,38 +533,6 @@ static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h)
n->pprev = &h->first;
}
/**
* hlist_add_head_rcu
* @n: the element to add to the hash list.
* @h: the list to add to.
*
* Description:
* Adds the specified element to the specified hlist,
* while permitting racing traversals.
*
* 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)
@ -847,63 +554,6 @@ static inline void hlist_add_after(struct hlist_node *n,
next->next->pprev = &next->next;
}
/**
* hlist_add_before_rcu
* @n: the new element to add to the hash list.
* @next: the existing element to add the new element before.
*
* Description:
* Adds the specified element to the specified hlist
* before the specified node while permitting racing traversals.
*
* 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
* @prev: the existing element to add the new element after.
* @n: the new element to add to the hash list.
*
* Description:
* Adds the specified element to the specified hlist
* after the specified node while permitting racing traversals.
*
* 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) \
@ -964,21 +614,4 @@ static inline void hlist_add_after_rcu(struct hlist_node *prev,
({ 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 cursor.
* @pos: the &struct hlist_node to use as a loop cursor.
* @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 = rcu_dereference((head)->first); \
pos && ({ prefetch(pos->next); 1;}) && \
({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \
pos = rcu_dereference(pos->next))
#endif

396
include/linux/rculist.h Normal file
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@ -0,0 +1,396 @@
#ifndef _LINUX_RCULIST_H
#define _LINUX_RCULIST_H
#ifdef __KERNEL__
/*
* RCU-protected list version
*/
#include <linux/list.h>
/*
* Insert a new entry between two known consecutive entries.
*
* This is only for internal list manipulation where we know
* the prev/next entries already!
*/
static inline void __list_add_rcu(struct list_head *new,
struct list_head *prev, struct list_head *next)
{
new->next = next;
new->prev = prev;
smp_wmb();
next->prev = new;
prev->next = new;
}
/**
* list_add_rcu - add a new entry to rcu-protected list
* @new: new entry to be added
* @head: list head to add it after
*
* Insert a new entry after the specified head.
* This is good for implementing stacks.
*
* The caller must take whatever precautions are necessary
* (such as holding appropriate locks) to avoid racing
* with another list-mutation primitive, such as list_add_rcu()
* or list_del_rcu(), running on this same list.
* However, it is perfectly legal to run concurrently with
* the _rcu list-traversal primitives, such as
* list_for_each_entry_rcu().
*/
static inline void list_add_rcu(struct list_head *new, struct list_head *head)
{
__list_add_rcu(new, head, head->next);
}
/**
* list_add_tail_rcu - add a new entry to rcu-protected list
* @new: new entry to be added
* @head: list head to add it before
*
* Insert a new entry before the specified head.
* This is useful for implementing queues.
*
* The caller must take whatever precautions are necessary
* (such as holding appropriate locks) to avoid racing
* with another list-mutation primitive, such as list_add_tail_rcu()
* or list_del_rcu(), running on this same list.
* However, it is perfectly legal to run concurrently with
* the _rcu list-traversal primitives, such as
* list_for_each_entry_rcu().
*/
static inline void list_add_tail_rcu(struct list_head *new,
struct list_head *head)
{
__list_add_rcu(new, head->prev, head);
}
/**
* list_del_rcu - deletes entry from list without re-initialization
* @entry: the element to delete from the list.
*
* Note: list_empty() 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 list.
*
* The caller must take whatever precautions are necessary
* (such as holding appropriate locks) to avoid racing
* with another list-mutation primitive, such as list_del_rcu()
* or list_add_rcu(), running on this same list.
* However, it is perfectly legal to run concurrently with
* the _rcu list-traversal primitives, such as
* list_for_each_entry_rcu().
*
* Note that the caller is not permitted to immediately free
* the newly deleted entry. Instead, either synchronize_rcu()
* or call_rcu() must be used to defer freeing until an RCU
* grace period has elapsed.
*/
static inline void list_del_rcu(struct list_head *entry)
{
__list_del(entry->prev, entry->next);
entry->prev = LIST_POISON2;
}
/**
* list_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.
* Note: @old should not be empty.
*/
static inline void list_replace_rcu(struct list_head *old,
struct list_head *new)
{
new->next = old->next;
new->prev = old->prev;
smp_wmb();
new->next->prev = new;
new->prev->next = new;
old->prev = LIST_POISON2;
}
/**
* list_splice_init_rcu - splice an RCU-protected list into an existing list.
* @list: the RCU-protected list to splice
* @head: the place in the list to splice the first list into
* @sync: function to sync: synchronize_rcu(), synchronize_sched(), ...
*
* @head can be RCU-read traversed concurrently with this function.
*
* Note that this function blocks.
*
* Important note: the caller must take whatever action is necessary to
* prevent any other updates to @head. In principle, it is possible
* to modify the list as soon as sync() begins execution.
* If this sort of thing becomes necessary, an alternative version
* based on call_rcu() could be created. But only if -really-
* needed -- there is no shortage of RCU API members.
*/
static inline void list_splice_init_rcu(struct list_head *list,
struct list_head *head,
void (*sync)(void))
{
struct list_head *first = list->next;
struct list_head *last = list->prev;
struct list_head *at = head->next;
if (list_empty(head))
return;
/* "first" and "last" tracking list, so initialize it. */
INIT_LIST_HEAD(list);
/*
* At this point, the list body still points to the source list.
* Wait for any readers to finish using the list before splicing
* the list body into the new list. Any new readers will see
* an empty list.
*/
sync();
/*
* Readers are finished with the source list, so perform splice.
* The order is important if the new list is global and accessible
* to concurrent RCU readers. Note that RCU readers are not
* permitted to traverse the prev pointers without excluding
* this function.
*/
last->next = at;
smp_wmb();
head->next = first;
first->prev = head;
at->prev = last;
}
/**
* list_for_each_rcu - iterate over an rcu-protected list
* @pos: the &struct list_head to use as a loop cursor.
* @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
* @pos: the &struct list_head to use as a loop cursor.
* @n: another &struct list_head to use as temporary storage
* @head: the head for your list.
*
* Iterate over an rcu-protected list, safe against removal of list entry.
*
* 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 cursor.
* @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
* @pos: the &struct list_head to use as a loop cursor.
* @head: the head for your list.
*
* Iterate over an rcu-protected list, continuing after current point.
*
* 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)
/**
* 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;
}
/**
* 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;
}
/**
* hlist_add_head_rcu
* @n: the element to add to the hash list.
* @h: the list to add to.
*
* Description:
* Adds the specified element to the specified hlist,
* while permitting racing traversals.
*
* 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;
}
/**
* hlist_add_before_rcu
* @n: the new element to add to the hash list.
* @next: the existing element to add the new element before.
*
* Description:
* Adds the specified element to the specified hlist
* before the specified node while permitting racing traversals.
*
* 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
* @prev: the existing element to add the new element after.
* @n: the new element to add to the hash list.
*
* Description:
* Adds the specified element to the specified hlist
* after the specified node while permitting racing traversals.
*
* 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;
}
/**
* hlist_for_each_entry_rcu - iterate over rcu list of given type
* @tpos: the type * to use as a loop cursor.
* @pos: the &struct hlist_node to use as a loop cursor.
* @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)
#endif /* __KERNEL__ */
#endif

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@ -30,6 +30,7 @@
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/rculist.h>
#include <linux/bootmem.h>
#include <linux/hash.h>
#include <linux/pid_namespace.h>

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@ -97,6 +97,7 @@
#include <linux/types.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/rculist.h>
#include <linux/rcupdate.h>
#include <linux/err.h>
#include <linux/textsearch.h>

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@ -20,6 +20,7 @@
#include <linux/mm.h>
#include <linux/in.h>
#include <linux/init.h>
#include <linux/rculist.h>
static LIST_HEAD(snap_list);
static DEFINE_SPINLOCK(snap_lock);

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@ -27,6 +27,7 @@
#include <linux/mm.h>
#include <linux/in.h>
#include <linux/init.h>
#include <linux/rculist.h>
#include <net/p8022.h>
#include <net/arp.h>
#include <linux/rtnetlink.h>

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@ -15,6 +15,7 @@
#include <linux/kernel.h>
#include <linux/init.h>
#include <linux/rculist.h>
#include <linux/spinlock.h>
#include <linux/times.h>
#include <linux/netdevice.h>

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@ -13,6 +13,7 @@
* 2 of the License, or (at your option) any later version.
*/
#include <linux/kernel.h>
#include <linux/rculist.h>
#include "br_private.h"
#include "br_private_stp.h"

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@ -30,8 +30,7 @@
*/
#include <linux/types.h>
#include <linux/rcupdate.h>
#include <linux/list.h>
#include <linux/rculist.h>
#include <linux/skbuff.h>
#include <linux/spinlock.h>
#include <linux/string.h>