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- /* SPDX-License-Identifier: GPL-2.0 */
- #ifndef _LINUX_RCULIST_H
- #define _LINUX_RCULIST_H
- #ifdef __KERNEL__
- /*
- * RCU-protected list version
- */
- #include <linux/list.h>
- #include <linux/rcupdate.h>
- /*
- * INIT_LIST_HEAD_RCU - Initialize a list_head visible to RCU readers
- * @list: list to be initialized
- *
- * You should instead use INIT_LIST_HEAD() for normal initialization and
- * cleanup tasks, when readers have no access to the list being initialized.
- * However, if the list being initialized is visible to readers, you
- * need to keep the compiler from being too mischievous.
- */
- static inline void INIT_LIST_HEAD_RCU(struct list_head *list)
- {
- WRITE_ONCE(list->next, list);
- WRITE_ONCE(list->prev, list);
- }
- /*
- * 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)))
- /**
- * list_tail_rcu - returns the prev pointer of the head of the list
- * @head: the head of the list
- *
- * Note: This should only be used with the list header, and even then
- * only if list_del() and similar primitives are not also used on the
- * list header.
- */
- #define list_tail_rcu(head) (*((struct list_head __rcu **)(&(head)->prev)))
- /*
- * Check during list traversal that we are within an RCU reader
- */
- #define check_arg_count_one(dummy)
- #ifdef CONFIG_PROVE_RCU_LIST
- #define __list_check_rcu(dummy, cond, extra...) \
- ({ \
- check_arg_count_one(extra); \
- RCU_LOCKDEP_WARN(!(cond) && !rcu_read_lock_any_held(), \
- "RCU-list traversed in non-reader section!"); \
- })
- #define __list_check_srcu(cond) \
- ({ \
- RCU_LOCKDEP_WARN(!(cond), \
- "RCU-list traversed without holding the required lock!");\
- })
- #else
- #define __list_check_rcu(dummy, cond, extra...) \
- ({ check_arg_count_one(extra); })
- #define __list_check_srcu(cond) ({ })
- #endif
- /*
- * 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)
- {
- if (!__list_add_valid(new, prev, next))
- return;
- new->next = next;
- new->prev = prev;
- rcu_assign_pointer(list_next_rcu(prev), new);
- next->prev = 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(entry);
- entry->prev = LIST_POISON2;
- }
- /**
- * hlist_del_init_rcu - deletes entry from hash list with re-initialization
- * @n: the element to delete from the hash list.
- *
- * Note: list_unhashed() on the node return true after this. It is
- * useful for RCU based read lockfree traversal if the writer side
- * must know if the list entry is still hashed or already unhashed.
- *
- * In particular, it means that we can not poison the forward pointers
- * that may still be used for walking the hash list and we can only
- * zero the pprev pointer so list_unhashed() will return true after
- * this.
- *
- * 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().
- */
- static inline void hlist_del_init_rcu(struct hlist_node *n)
- {
- if (!hlist_unhashed(n)) {
- __hlist_del(n);
- WRITE_ONCE(n->pprev, NULL);
- }
- }
- /**
- * 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;
- rcu_assign_pointer(list_next_rcu(new->prev), new);
- new->next->prev = new;
- old->prev = LIST_POISON2;
- }
- /**
- * __list_splice_init_rcu - join an RCU-protected list into an existing list.
- * @list: the RCU-protected list to splice
- * @prev: points to the last element of the existing list
- * @next: points to the first element of the existing list
- * @sync: synchronize_rcu, synchronize_rcu_expedited, ...
- *
- * The list pointed to by @prev and @next 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 the existing list. 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 *prev,
- struct list_head *next,
- void (*sync)(void))
- {
- struct list_head *first = list->next;
- struct list_head *last = list->prev;
- /*
- * "first" and "last" tracking list, so initialize it. RCU readers
- * have access to this list, so we must use INIT_LIST_HEAD_RCU()
- * instead of INIT_LIST_HEAD().
- */
- INIT_LIST_HEAD_RCU(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();
- ASSERT_EXCLUSIVE_ACCESS(*first);
- ASSERT_EXCLUSIVE_ACCESS(*last);
- /*
- * 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 = next;
- rcu_assign_pointer(list_next_rcu(prev), first);
- first->prev = prev;
- next->prev = last;
- }
- /**
- * list_splice_init_rcu - splice an RCU-protected list into an existing list,
- * designed for stacks.
- * @list: the RCU-protected list to splice
- * @head: the place in the existing list to splice the first list into
- * @sync: synchronize_rcu, synchronize_rcu_expedited, ...
- */
- static inline void list_splice_init_rcu(struct list_head *list,
- struct list_head *head,
- void (*sync)(void))
- {
- if (!list_empty(list))
- __list_splice_init_rcu(list, head, head->next, sync);
- }
- /**
- * list_splice_tail_init_rcu - splice an RCU-protected list into an existing
- * list, designed for queues.
- * @list: the RCU-protected list to splice
- * @head: the place in the existing list to splice the first list into
- * @sync: synchronize_rcu, synchronize_rcu_expedited, ...
- */
- static inline void list_splice_tail_init_rcu(struct list_head *list,
- struct list_head *head,
- void (*sync)(void))
- {
- if (!list_empty(list))
- __list_splice_init_rcu(list, head->prev, head, sync);
- }
- /**
- * list_entry_rcu - get the struct for this entry
- * @ptr: the &struct list_head pointer.
- * @type: the type of the struct this is embedded in.
- * @member: the name of the list_head within the struct.
- *
- * This primitive may safely run concurrently with the _rcu list-mutation
- * 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(READ_ONCE(ptr), type, member)
- /*
- * Where are list_empty_rcu() and list_first_entry_rcu()?
- *
- * They do not exist because they would lead to subtle race conditions:
- *
- * if (!list_empty_rcu(mylist)) {
- * struct foo *bar = list_first_entry_rcu(mylist, struct foo, list_member);
- * do_something(bar);
- * }
- *
- * The list might be non-empty when list_empty_rcu() checks it, but it
- * might have become empty by the time that list_first_entry_rcu() rereads
- * the ->next pointer, which would result in a SEGV.
- *
- * When not using RCU, it is OK for list_first_entry() to re-read that
- * pointer because both functions should be protected by some lock that
- * blocks writers.
- *
- * When using RCU, list_empty() uses READ_ONCE() to fetch the
- * RCU-protected ->next pointer and then compares it to the address of the
- * list head. However, it neither dereferences this pointer nor provides
- * this pointer to its caller. Thus, READ_ONCE() suffices (that is,
- * rcu_dereference() is not needed), which means that list_empty() can be
- * used anywhere you would want to use list_empty_rcu(). Just don't
- * expect anything useful to happen if you do a subsequent lockless
- * call to list_first_entry_rcu()!!!
- *
- * See list_first_or_null_rcu for an alternative.
- */
- /**
- * list_first_or_null_rcu - get the first element from a list
- * @ptr: the list head to take the element from.
- * @type: the type of the struct this is embedded in.
- * @member: the name of the list_head within the struct.
- *
- * Note that if the list is empty, it returns NULL.
- *
- * This primitive may safely run concurrently with the _rcu list-mutation
- * primitives such as list_add_rcu() as long as it's guarded by rcu_read_lock().
- */
- #define list_first_or_null_rcu(ptr, type, member) \
- ({ \
- struct list_head *__ptr = (ptr); \
- struct list_head *__next = READ_ONCE(__ptr->next); \
- likely(__ptr != __next) ? list_entry_rcu(__next, type, member) : NULL; \
- })
- /**
- * list_next_or_null_rcu - get the first element from a list
- * @head: the head for the list.
- * @ptr: the list head to take the next element from.
- * @type: the type of the struct this is embedded in.
- * @member: the name of the list_head within the struct.
- *
- * Note that if the ptr is at the end of the list, NULL is returned.
- *
- * This primitive may safely run concurrently with the _rcu list-mutation
- * primitives such as list_add_rcu() as long as it's guarded by rcu_read_lock().
- */
- #define list_next_or_null_rcu(head, ptr, type, member) \
- ({ \
- struct list_head *__head = (head); \
- struct list_head *__ptr = (ptr); \
- struct list_head *__next = READ_ONCE(__ptr->next); \
- likely(__next != __head) ? list_entry_rcu(__next, type, \
- member) : NULL; \
- })
- /**
- * 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_head within the struct.
- * @cond: optional lockdep expression if called from non-RCU protection.
- *
- * 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, cond...) \
- for (__list_check_rcu(dummy, ## cond, 0), \
- pos = list_entry_rcu((head)->next, typeof(*pos), member); \
- &pos->member != (head); \
- pos = list_entry_rcu(pos->member.next, typeof(*pos), member))
- /**
- * list_for_each_entry_srcu - 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_head within the struct.
- * @cond: lockdep expression for the lock required to traverse the 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 srcu_read_lock().
- * The lockdep expression srcu_read_lock_held() can be passed as the
- * cond argument from read side.
- */
- #define list_for_each_entry_srcu(pos, head, member, cond) \
- for (__list_check_srcu(cond), \
- pos = list_entry_rcu((head)->next, typeof(*pos), member); \
- &pos->member != (head); \
- pos = list_entry_rcu(pos->member.next, typeof(*pos), member))
- /**
- * list_entry_lockless - get the struct for this entry
- * @ptr: the &struct list_head pointer.
- * @type: the type of the struct this is embedded in.
- * @member: the name of the list_head within the struct.
- *
- * This primitive may safely run concurrently with the _rcu
- * list-mutation primitives such as list_add_rcu(), but requires some
- * implicit RCU read-side guarding. One example is running within a special
- * exception-time environment where preemption is disabled and where lockdep
- * cannot be invoked. Another example is when items are added to the list,
- * but never deleted.
- */
- #define list_entry_lockless(ptr, type, member) \
- container_of((typeof(ptr))READ_ONCE(ptr), type, member)
- /**
- * list_for_each_entry_lockless - 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 primitive may safely run concurrently with the _rcu
- * list-mutation primitives such as list_add_rcu(), but requires some
- * implicit RCU read-side guarding. One example is running within a special
- * exception-time environment where preemption is disabled and where lockdep
- * cannot be invoked. Another example is when items are added to the list,
- * but never deleted.
- */
- #define list_for_each_entry_lockless(pos, head, member) \
- for (pos = list_entry_lockless((head)->next, typeof(*pos), member); \
- &pos->member != (head); \
- pos = list_entry_lockless(pos->member.next, typeof(*pos), member))
- /**
- * 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_head within the struct.
- *
- * Continue to iterate over list of given type, continuing after
- * the current position which must have been in the list when the RCU read
- * lock was taken.
- * This would typically require either that you obtained the node from a
- * previous walk of the list in the same RCU read-side critical section, or
- * that you held some sort of non-RCU reference (such as a reference count)
- * to keep the node alive *and* in the list.
- *
- * This iterator is similar to list_for_each_entry_from_rcu() except
- * this starts after the given position and that one starts at the given
- * position.
- */
- #define list_for_each_entry_continue_rcu(pos, head, member) \
- for (pos = list_entry_rcu(pos->member.next, typeof(*pos), member); \
- &pos->member != (head); \
- pos = list_entry_rcu(pos->member.next, typeof(*pos), member))
- /**
- * list_for_each_entry_from_rcu - iterate over a list from current point
- * @pos: the type * to use as a loop cursor.
- * @head: the head for your list.
- * @member: the name of the list_node within the struct.
- *
- * Iterate over the tail of a list starting from a given position,
- * which must have been in the list when the RCU read lock was taken.
- * This would typically require either that you obtained the node from a
- * previous walk of the list in the same RCU read-side critical section, or
- * that you held some sort of non-RCU reference (such as a reference count)
- * to keep the node alive *and* in the list.
- *
- * This iterator is similar to list_for_each_entry_continue_rcu() except
- * this starts from the given position and that one starts from the position
- * after the given position.
- */
- #define list_for_each_entry_from_rcu(pos, head, member) \
- for (; &(pos)->member != (head); \
- pos = list_entry_rcu(pos->member.next, typeof(*(pos)), member))
- /**
- * 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);
- WRITE_ONCE(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;
- WRITE_ONCE(new->pprev, old->pprev);
- rcu_assign_pointer(*(struct hlist_node __rcu **)new->pprev, new);
- if (next)
- WRITE_ONCE(new->next->pprev, &new->next);
- WRITE_ONCE(old->pprev, LIST_POISON2);
- }
- /**
- * hlists_swap_heads_rcu - swap the lists the hlist heads point to
- * @left: The hlist head on the left
- * @right: The hlist head on the right
- *
- * The lists start out as [@left ][node1 ... ] and
- * [@right ][node2 ... ]
- * The lists end up as [@left ][node2 ... ]
- * [@right ][node1 ... ]
- */
- static inline void hlists_swap_heads_rcu(struct hlist_head *left, struct hlist_head *right)
- {
- struct hlist_node *node1 = left->first;
- struct hlist_node *node2 = right->first;
- rcu_assign_pointer(left->first, node2);
- rcu_assign_pointer(right->first, node1);
- WRITE_ONCE(node2->pprev, &left->first);
- WRITE_ONCE(node1->pprev, &right->first);
- }
- /*
- * 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.
- * @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;
- WRITE_ONCE(n->pprev, &h->first);
- rcu_assign_pointer(hlist_first_rcu(h), n);
- if (first)
- WRITE_ONCE(first->pprev, &n->next);
- }
- /**
- * hlist_add_tail_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_tail_rcu(struct hlist_node *n,
- struct hlist_head *h)
- {
- struct hlist_node *i, *last = NULL;
- /* Note: write side code, so rcu accessors are not needed. */
- for (i = h->first; i; i = i->next)
- last = i;
- if (last) {
- n->next = last->next;
- WRITE_ONCE(n->pprev, &last->next);
- rcu_assign_pointer(hlist_next_rcu(last), n);
- } else {
- hlist_add_head_rcu(n, h);
- }
- }
- /**
- * 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)
- {
- WRITE_ONCE(n->pprev, next->pprev);
- n->next = next;
- rcu_assign_pointer(hlist_pprev_rcu(n), n);
- WRITE_ONCE(next->pprev, &n->next);
- }
- /**
- * hlist_add_behind_rcu
- * @n: the new element to add to the hash list.
- * @prev: the existing element to add the new element after.
- *
- * 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_behind_rcu(struct hlist_node *n,
- struct hlist_node *prev)
- {
- n->next = prev->next;
- WRITE_ONCE(n->pprev, &prev->next);
- rcu_assign_pointer(hlist_next_rcu(prev), n);
- if (n->next)
- WRITE_ONCE(n->next->pprev, &n->next);
- }
- #define __hlist_for_each_rcu(pos, head) \
- for (pos = rcu_dereference(hlist_first_rcu(head)); \
- pos; \
- pos = rcu_dereference(hlist_next_rcu(pos)))
- /**
- * hlist_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 hlist_node within the struct.
- * @cond: optional lockdep expression if called from non-RCU protection.
- *
- * 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(pos, head, member, cond...) \
- for (__list_check_rcu(dummy, ## cond, 0), \
- pos = hlist_entry_safe(rcu_dereference_raw(hlist_first_rcu(head)),\
- typeof(*(pos)), member); \
- pos; \
- pos = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(\
- &(pos)->member)), typeof(*(pos)), member))
- /**
- * hlist_for_each_entry_srcu - 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 hlist_node within the struct.
- * @cond: lockdep expression for the lock required to traverse the list.
- *
- * 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 srcu_read_lock().
- * The lockdep expression srcu_read_lock_held() can be passed as the
- * cond argument from read side.
- */
- #define hlist_for_each_entry_srcu(pos, head, member, cond) \
- for (__list_check_srcu(cond), \
- pos = hlist_entry_safe(rcu_dereference_raw(hlist_first_rcu(head)),\
- typeof(*(pos)), member); \
- pos; \
- pos = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu(\
- &(pos)->member)), typeof(*(pos)), member))
- /**
- * hlist_for_each_entry_rcu_notrace - iterate over rcu list of given type (for tracing)
- * @pos: the type * 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().
- *
- * This is the same as hlist_for_each_entry_rcu() except that it does
- * not do any RCU debugging or tracing.
- */
- #define hlist_for_each_entry_rcu_notrace(pos, head, member) \
- for (pos = hlist_entry_safe(rcu_dereference_raw_check(hlist_first_rcu(head)),\
- typeof(*(pos)), member); \
- pos; \
- pos = hlist_entry_safe(rcu_dereference_raw_check(hlist_next_rcu(\
- &(pos)->member)), typeof(*(pos)), member))
- /**
- * hlist_for_each_entry_rcu_bh - 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 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(pos, head, member) \
- for (pos = hlist_entry_safe(rcu_dereference_bh(hlist_first_rcu(head)),\
- typeof(*(pos)), member); \
- pos; \
- pos = hlist_entry_safe(rcu_dereference_bh(hlist_next_rcu(\
- &(pos)->member)), typeof(*(pos)), member))
- /**
- * hlist_for_each_entry_continue_rcu - iterate over a hlist continuing after current point
- * @pos: the type * to use as a loop cursor.
- * @member: the name of the hlist_node within the struct.
- */
- #define hlist_for_each_entry_continue_rcu(pos, member) \
- for (pos = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu( \
- &(pos)->member)), typeof(*(pos)), member); \
- pos; \
- pos = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu( \
- &(pos)->member)), typeof(*(pos)), member))
- /**
- * hlist_for_each_entry_continue_rcu_bh - iterate over a hlist continuing after current point
- * @pos: the type * to use as a loop cursor.
- * @member: the name of the hlist_node within the struct.
- */
- #define hlist_for_each_entry_continue_rcu_bh(pos, member) \
- for (pos = hlist_entry_safe(rcu_dereference_bh(hlist_next_rcu( \
- &(pos)->member)), typeof(*(pos)), member); \
- pos; \
- pos = hlist_entry_safe(rcu_dereference_bh(hlist_next_rcu( \
- &(pos)->member)), typeof(*(pos)), member))
- /**
- * hlist_for_each_entry_from_rcu - iterate over a hlist continuing from current point
- * @pos: the type * to use as a loop cursor.
- * @member: the name of the hlist_node within the struct.
- */
- #define hlist_for_each_entry_from_rcu(pos, member) \
- for (; pos; \
- pos = hlist_entry_safe(rcu_dereference_raw(hlist_next_rcu( \
- &(pos)->member)), typeof(*(pos)), member))
- #endif /* __KERNEL__ */
- #endif
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