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>

1 files changed, 0 insertions, 367 deletions

diff --git a/include/linux/list.h b/include/linux/list.h
index 08cf4f651889..139ec41d9c2e 100644
--- a/include/linux/list.h
+++ b/include/linux/list.h
@@ -85,65 +85,6 @@ static inline void list_add_tail(struct list_head *new, struct list_head *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.
  *
@@ -174,36 +115,6 @@ 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
  * @new : the new element to insert
@@ -227,25 +138,6 @@ static inline void list_replace_init(struct 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.
  */
@@ -369,62 +261,6 @@ 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.
  * @type:       the type of the struct this is embedded in.
@@ -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