diff options
Diffstat (limited to 'include/linux/rculist.h')
-rw-r--r-- | include/linux/rculist.h | 116 |
1 files changed, 98 insertions, 18 deletions
diff --git a/include/linux/rculist.h b/include/linux/rculist.h index 5710f43bbc9e..2dea94fc4402 100644 --- a/include/linux/rculist.h +++ b/include/linux/rculist.h @@ -10,6 +10,21 @@ #include <linux/rcupdate.h> /* + * Why is there no list_empty_rcu()? Because list_empty() serves this + * purpose. The list_empty() function fetches the RCU-protected pointer + * and compares it to the address of the list head, but neither dereferences + * this pointer itself nor provides this pointer to the caller. Therefore, + * it is not necessary to use rcu_dereference(), so that list_empty() can + * be used anywhere you would want to use a list_empty_rcu(). + */ + +/* + * return the ->next pointer of a list_head in an rcu safe + * way, we must not access it directly + */ +#define list_next_rcu(list) (*((struct list_head __rcu **)(&(list)->next))) + +/* * Insert a new entry between two known consecutive entries. * * This is only for internal list manipulation where we know @@ -20,7 +35,7 @@ static inline void __list_add_rcu(struct list_head *new, { new->next = next; new->prev = prev; - rcu_assign_pointer(prev->next, new); + rcu_assign_pointer(list_next_rcu(prev), new); next->prev = new; } @@ -138,7 +153,7 @@ static inline void list_replace_rcu(struct list_head *old, { new->next = old->next; new->prev = old->prev; - rcu_assign_pointer(new->prev->next, new); + rcu_assign_pointer(list_next_rcu(new->prev), new); new->next->prev = new; old->prev = LIST_POISON2; } @@ -193,7 +208,7 @@ static inline void list_splice_init_rcu(struct list_head *list, */ last->next = at; - rcu_assign_pointer(head->next, first); + rcu_assign_pointer(list_next_rcu(head), first); first->prev = head; at->prev = last; } @@ -208,7 +223,9 @@ static inline void list_splice_init_rcu(struct list_head *list, * primitives such as list_add_rcu() as long as it's guarded by rcu_read_lock(). */ #define list_entry_rcu(ptr, type, member) \ - container_of(rcu_dereference(ptr), type, member) + ({typeof (*ptr) __rcu *__ptr = (typeof (*ptr) __rcu __force *)ptr; \ + container_of((typeof(ptr))rcu_dereference_raw(__ptr), type, member); \ + }) /** * list_first_entry_rcu - get the first element from a list @@ -224,11 +241,6 @@ static inline void list_splice_init_rcu(struct list_head *list, #define list_first_entry_rcu(ptr, type, member) \ list_entry_rcu((ptr)->next, type, member) -#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. @@ -257,9 +269,23 @@ static inline void list_splice_init_rcu(struct list_head *list, * 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); \ + for ((pos) = rcu_dereference_raw(list_next_rcu(pos)); \ prefetch((pos)->next), (pos) != (head); \ - (pos) = rcu_dereference((pos)->next)) + (pos) = rcu_dereference_raw(list_next_rcu(pos))) + +/** + * list_for_each_entry_continue_rcu - continue iteration over 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. + * + * Continue to iterate over list of given type, continuing after + * the current position. + */ +#define list_for_each_entry_continue_rcu(pos, head, member) \ + for (pos = list_entry_rcu(pos->member.next, typeof(*pos), member); \ + prefetch(pos->member.next), &pos->member != (head); \ + pos = list_entry_rcu(pos->member.next, typeof(*pos), member)) /** * hlist_del_rcu - deletes entry from hash list without re-initialization @@ -300,12 +326,19 @@ static inline void hlist_replace_rcu(struct hlist_node *old, new->next = next; new->pprev = old->pprev; - rcu_assign_pointer(*new->pprev, new); + rcu_assign_pointer(*(struct hlist_node __rcu **)new->pprev, new); if (next) new->next->pprev = &new->next; old->pprev = LIST_POISON2; } +/* + * return the first or the next element in an RCU protected hlist + */ +#define hlist_first_rcu(head) (*((struct hlist_node __rcu **)(&(head)->first))) +#define hlist_next_rcu(node) (*((struct hlist_node __rcu **)(&(node)->next))) +#define hlist_pprev_rcu(node) (*((struct hlist_node __rcu **)((node)->pprev))) + /** * hlist_add_head_rcu * @n: the element to add to the hash list. @@ -332,7 +365,7 @@ static inline void hlist_add_head_rcu(struct hlist_node *n, n->next = first; n->pprev = &h->first; - rcu_assign_pointer(h->first, n); + rcu_assign_pointer(hlist_first_rcu(h), n); if (first) first->pprev = &n->next; } @@ -360,7 +393,7 @@ static inline void hlist_add_before_rcu(struct hlist_node *n, { n->pprev = next->pprev; n->next = next; - rcu_assign_pointer(*(n->pprev), n); + rcu_assign_pointer(hlist_pprev_rcu(n), n); next->pprev = &n->next; } @@ -387,11 +420,16 @@ static inline void hlist_add_after_rcu(struct hlist_node *prev, { n->next = prev->next; n->pprev = &prev->next; - rcu_assign_pointer(prev->next, n); + rcu_assign_pointer(hlist_next_rcu(prev), n); if (n->next) n->next->pprev = &n->next; } +#define __hlist_for_each_rcu(pos, head) \ + for (pos = rcu_dereference(hlist_first_rcu(head)); \ + pos && ({ prefetch(pos->next); 1; }); \ + pos = rcu_dereference(hlist_next_rcu(pos))) + /** * hlist_for_each_entry_rcu - iterate over rcu list of given type * @tpos: the type * to use as a loop cursor. @@ -403,11 +441,53 @@ static inline void hlist_add_after_rcu(struct hlist_node *prev, * 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); \ +#define hlist_for_each_entry_rcu(tpos, pos, head, member) \ + for (pos = rcu_dereference_raw(hlist_first_rcu(head)); \ + pos && ({ prefetch(pos->next); 1; }) && \ + ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1; }); \ + pos = rcu_dereference_raw(hlist_next_rcu(pos))) + +/** + * hlist_for_each_entry_rcu_bh - 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_bh(tpos, pos, head, member) \ + for (pos = rcu_dereference_bh((head)->first); \ pos && ({ prefetch(pos->next); 1; }) && \ ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1; }); \ - pos = rcu_dereference(pos->next)) + pos = rcu_dereference_bh(pos->next)) + +/** + * hlist_for_each_entry_continue_rcu - iterate over a hlist continuing after current point + * @tpos: the type * to use as a loop cursor. + * @pos: the &struct hlist_node to use as a loop cursor. + * @member: the name of the hlist_node within the struct. + */ +#define hlist_for_each_entry_continue_rcu(tpos, pos, member) \ + for (pos = rcu_dereference((pos)->next); \ + pos && ({ prefetch(pos->next); 1; }) && \ + ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1; }); \ + pos = rcu_dereference(pos->next)) + +/** + * hlist_for_each_entry_continue_rcu_bh - iterate over a hlist continuing after current point + * @tpos: the type * to use as a loop cursor. + * @pos: the &struct hlist_node to use as a loop cursor. + * @member: the name of the hlist_node within the struct. + */ +#define hlist_for_each_entry_continue_rcu_bh(tpos, pos, member) \ + for (pos = rcu_dereference_bh((pos)->next); \ + pos && ({ prefetch(pos->next); 1; }) && \ + ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1; }); \ + pos = rcu_dereference_bh(pos->next)) + #endif /* __KERNEL__ */ #endif |