diff options
Diffstat (limited to 'include/linux')
| -rw-r--r-- | include/linux/list.h | 136 | ||||
| -rw-r--r-- | include/linux/list_nulls.h | 30 | ||||
| -rw-r--r-- | include/linux/rcu_segcblist.h | 2 | ||||
| -rw-r--r-- | include/linux/rculist.h | 38 | ||||
| -rw-r--r-- | include/linux/rculist_nulls.h | 20 | ||||
| -rw-r--r-- | include/linux/rcupdate.h | 28 | ||||
| -rw-r--r-- | include/linux/rcutiny.h | 1 | ||||
| -rw-r--r-- | include/linux/rcutree.h | 1 |
8 files changed, 186 insertions, 70 deletions
diff --git a/include/linux/list.h b/include/linux/list.h index 85c92555e31f..4f3b7f71bdfd 100644 --- a/include/linux/list.h +++ b/include/linux/list.h @@ -23,6 +23,13 @@ #define LIST_HEAD(name) \ struct list_head name = LIST_HEAD_INIT(name) +/** + * INIT_LIST_HEAD - Initialize a list_head structure + * @list: list_head structure to be initialized. + * + * Initializes the list_head to point to itself. If it is a list header, + * the result is an empty list. + */ static inline void INIT_LIST_HEAD(struct list_head *list) { WRITE_ONCE(list->next, list); @@ -120,12 +127,6 @@ static inline void __list_del_clearprev(struct list_head *entry) entry->prev = NULL; } -/** - * list_del - deletes entry from list. - * @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. - */ static inline void __list_del_entry(struct list_head *entry) { if (!__list_del_entry_valid(entry)) @@ -134,6 +135,12 @@ static inline void __list_del_entry(struct list_head *entry) __list_del(entry->prev, entry->next); } +/** + * list_del - deletes entry from list. + * @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. + */ static inline void list_del(struct list_head *entry) { __list_del_entry(entry); @@ -157,8 +164,15 @@ static inline void list_replace(struct list_head *old, new->prev->next = new; } +/** + * list_replace_init - replace old entry by new one and initialize the old one + * @old : the element to be replaced + * @new : the new element to insert + * + * If @old was empty, it will be overwritten. + */ static inline void list_replace_init(struct list_head *old, - struct list_head *new) + struct list_head *new) { list_replace(old, new); INIT_LIST_HEAD(old); @@ -744,11 +758,36 @@ static inline void INIT_HLIST_NODE(struct hlist_node *h) h->pprev = NULL; } +/** + * hlist_unhashed - Has node been removed from list and reinitialized? + * @h: Node to be checked + * + * Not that not all removal functions will leave a node in unhashed + * state. For example, hlist_nulls_del_init_rcu() does leave the + * node in unhashed state, but hlist_nulls_del() does not. + */ static inline int hlist_unhashed(const struct hlist_node *h) { return !h->pprev; } +/** + * hlist_unhashed_lockless - Version of hlist_unhashed for lockless use + * @h: Node to be checked + * + * This variant of hlist_unhashed() must be used in lockless contexts + * to avoid potential load-tearing. The READ_ONCE() is paired with the + * various WRITE_ONCE() in hlist helpers that are defined below. + */ +static inline int hlist_unhashed_lockless(const struct hlist_node *h) +{ + return !READ_ONCE(h->pprev); +} + +/** + * hlist_empty - Is the specified hlist_head structure an empty hlist? + * @h: Structure to check. + */ static inline int hlist_empty(const struct hlist_head *h) { return !READ_ONCE(h->first); @@ -761,9 +800,16 @@ static inline void __hlist_del(struct hlist_node *n) WRITE_ONCE(*pprev, next); if (next) - next->pprev = pprev; + WRITE_ONCE(next->pprev, pprev); } +/** + * hlist_del - Delete the specified hlist_node from its list + * @n: Node to delete. + * + * Note that this function leaves the node in hashed state. Use + * hlist_del_init() or similar instead to unhash @n. + */ static inline void hlist_del(struct hlist_node *n) { __hlist_del(n); @@ -771,6 +817,12 @@ static inline void hlist_del(struct hlist_node *n) n->pprev = LIST_POISON2; } +/** + * hlist_del_init - Delete the specified hlist_node from its list and initialize + * @n: Node to delete. + * + * Note that this function leaves the node in unhashed state. + */ static inline void hlist_del_init(struct hlist_node *n) { if (!hlist_unhashed(n)) { @@ -779,51 +831,83 @@ static inline void hlist_del_init(struct hlist_node *n) } } +/** + * hlist_add_head - add a new entry at the beginning of the hlist + * @n: new entry to be added + * @h: hlist head to add it after + * + * Insert a new entry after the specified head. + * This is good for implementing stacks. + */ static inline void hlist_add_head(struct hlist_node *n, struct hlist_head *h) { struct hlist_node *first = h->first; - n->next = first; + WRITE_ONCE(n->next, first); if (first) - first->pprev = &n->next; + WRITE_ONCE(first->pprev, &n->next); WRITE_ONCE(h->first, n); - n->pprev = &h->first; + WRITE_ONCE(n->pprev, &h->first); } -/* next must be != NULL */ +/** + * hlist_add_before - add a new entry before the one specified + * @n: new entry to be added + * @next: hlist node to add it before, which must be non-NULL + */ static inline void hlist_add_before(struct hlist_node *n, - struct hlist_node *next) + struct hlist_node *next) { - n->pprev = next->pprev; - n->next = next; - next->pprev = &n->next; + WRITE_ONCE(n->pprev, next->pprev); + WRITE_ONCE(n->next, next); + WRITE_ONCE(next->pprev, &n->next); WRITE_ONCE(*(n->pprev), n); } +/** + * hlist_add_behing - add a new entry after the one specified + * @n: new entry to be added + * @prev: hlist node to add it after, which must be non-NULL + */ static inline void hlist_add_behind(struct hlist_node *n, struct hlist_node *prev) { - n->next = prev->next; - prev->next = n; - n->pprev = &prev->next; + WRITE_ONCE(n->next, prev->next); + WRITE_ONCE(prev->next, n); + WRITE_ONCE(n->pprev, &prev->next); if (n->next) - n->next->pprev = &n->next; + WRITE_ONCE(n->next->pprev, &n->next); } -/* after that we'll appear to be on some hlist and hlist_del will work */ +/** + * hlist_add_fake - create a fake hlist consisting of a single headless node + * @n: Node to make a fake list out of + * + * This makes @n appear to be its own predecessor on a headless hlist. + * The point of this is to allow things like hlist_del() to work correctly + * in cases where there is no list. + */ static inline void hlist_add_fake(struct hlist_node *n) { n->pprev = &n->next; } +/** + * hlist_fake: Is this node a fake hlist? + * @h: Node to check for being a self-referential fake hlist. + */ static inline bool hlist_fake(struct hlist_node *h) { return h->pprev == &h->next; } -/* +/** + * hlist_is_singular_node - is node the only element of the specified hlist? + * @n: Node to check for singularity. + * @h: Header for potentially singular list. + * * Check whether the node is the only node of the head without - * accessing head: + * accessing head, thus avoiding unnecessary cache misses. */ static inline bool hlist_is_singular_node(struct hlist_node *n, struct hlist_head *h) @@ -831,7 +915,11 @@ hlist_is_singular_node(struct hlist_node *n, struct hlist_head *h) return !n->next && n->pprev == &h->first; } -/* +/** + * hlist_move_list - Move an hlist + * @old: hlist_head for old list. + * @new: hlist_head for new list. + * * Move a list from one list head to another. Fixup the pprev * reference of the first entry if it exists. */ diff --git a/include/linux/list_nulls.h b/include/linux/list_nulls.h index 3ef96743db8d..fa6e8471bd22 100644 --- a/include/linux/list_nulls.h +++ b/include/linux/list_nulls.h @@ -56,11 +56,33 @@ static inline unsigned long get_nulls_value(const struct hlist_nulls_node *ptr) return ((unsigned long)ptr) >> 1; } +/** + * hlist_nulls_unhashed - Has node been removed and reinitialized? + * @h: Node to be checked + * + * Not that not all removal functions will leave a node in unhashed state. + * For example, hlist_del_init_rcu() leaves the node in unhashed state, + * but hlist_nulls_del() does not. + */ static inline int hlist_nulls_unhashed(const struct hlist_nulls_node *h) { return !h->pprev; } +/** + * hlist_nulls_unhashed_lockless - Has node been removed and reinitialized? + * @h: Node to be checked + * + * Not that not all removal functions will leave a node in unhashed state. + * For example, hlist_del_init_rcu() leaves the node in unhashed state, + * but hlist_nulls_del() does not. Unlike hlist_nulls_unhashed(), this + * function may be used locklessly. + */ +static inline int hlist_nulls_unhashed_lockless(const struct hlist_nulls_node *h) +{ + return !READ_ONCE(h->pprev); +} + static inline int hlist_nulls_empty(const struct hlist_nulls_head *h) { return is_a_nulls(READ_ONCE(h->first)); @@ -72,10 +94,10 @@ static inline void hlist_nulls_add_head(struct hlist_nulls_node *n, struct hlist_nulls_node *first = h->first; n->next = first; - n->pprev = &h->first; + WRITE_ONCE(n->pprev, &h->first); h->first = n; if (!is_a_nulls(first)) - first->pprev = &n->next; + WRITE_ONCE(first->pprev, &n->next); } static inline void __hlist_nulls_del(struct hlist_nulls_node *n) @@ -85,13 +107,13 @@ static inline void __hlist_nulls_del(struct hlist_nulls_node *n) WRITE_ONCE(*pprev, next); if (!is_a_nulls(next)) - next->pprev = pprev; + WRITE_ONCE(next->pprev, pprev); } static inline void hlist_nulls_del(struct hlist_nulls_node *n) { __hlist_nulls_del(n); - n->pprev = LIST_POISON2; + WRITE_ONCE(n->pprev, LIST_POISON2); } /** diff --git a/include/linux/rcu_segcblist.h b/include/linux/rcu_segcblist.h index 646759042333..b36afe7b22c9 100644 --- a/include/linux/rcu_segcblist.h +++ b/include/linux/rcu_segcblist.h @@ -22,7 +22,6 @@ struct rcu_cblist { struct rcu_head *head; struct rcu_head **tail; long len; - long len_lazy; }; #define RCU_CBLIST_INITIALIZER(n) { .head = NULL, .tail = &n.head } @@ -73,7 +72,6 @@ struct rcu_segcblist { #else long len; #endif - long len_lazy; u8 enabled; u8 offloaded; }; diff --git a/include/linux/rculist.h b/include/linux/rculist.h index 4158b7212936..9f313e4999fe 100644 --- a/include/linux/rculist.h +++ b/include/linux/rculist.h @@ -40,6 +40,16 @@ static inline void INIT_LIST_HEAD_RCU(struct list_head *list) */ #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 */ @@ -173,7 +183,7 @@ static inline void hlist_del_init_rcu(struct hlist_node *n) { if (!hlist_unhashed(n)) { __hlist_del(n); - n->pprev = NULL; + WRITE_ONCE(n->pprev, NULL); } } @@ -361,7 +371,7 @@ static inline void list_splice_tail_init_rcu(struct list_head *list, * @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. + * @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() @@ -473,7 +483,7 @@ static inline void list_splice_tail_init_rcu(struct list_head *list, static inline void hlist_del_rcu(struct hlist_node *n) { __hlist_del(n); - n->pprev = LIST_POISON2; + WRITE_ONCE(n->pprev, LIST_POISON2); } /** @@ -489,11 +499,11 @@ static inline void hlist_replace_rcu(struct hlist_node *old, struct hlist_node *next = old->next; new->next = next; - new->pprev = old->pprev; + WRITE_ONCE(new->pprev, old->pprev); rcu_assign_pointer(*(struct hlist_node __rcu **)new->pprev, new); if (next) - new->next->pprev = &new->next; - old->pprev = LIST_POISON2; + WRITE_ONCE(new->next->pprev, &new->next); + WRITE_ONCE(old->pprev, LIST_POISON2); } /* @@ -528,10 +538,10 @@ static inline void hlist_add_head_rcu(struct hlist_node *n, struct hlist_node *first = h->first; n->next = first; - n->pprev = &h->first; + WRITE_ONCE(n->pprev, &h->first); rcu_assign_pointer(hlist_first_rcu(h), n); if (first) - first->pprev = &n->next; + WRITE_ONCE(first->pprev, &n->next); } /** @@ -564,7 +574,7 @@ static inline void hlist_add_tail_rcu(struct hlist_node *n, if (last) { n->next = last->next; - n->pprev = &last->next; + WRITE_ONCE(n->pprev, &last->next); rcu_assign_pointer(hlist_next_rcu(last), n); } else { hlist_add_head_rcu(n, h); @@ -592,10 +602,10 @@ static inline void hlist_add_tail_rcu(struct hlist_node *n, static inline void hlist_add_before_rcu(struct hlist_node *n, struct hlist_node *next) { - n->pprev = next->pprev; + WRITE_ONCE(n->pprev, next->pprev); n->next = next; rcu_assign_pointer(hlist_pprev_rcu(n), n); - next->pprev = &n->next; + WRITE_ONCE(next->pprev, &n->next); } /** @@ -620,10 +630,10 @@ static inline void hlist_add_behind_rcu(struct hlist_node *n, struct hlist_node *prev) { n->next = prev->next; - n->pprev = &prev->next; + WRITE_ONCE(n->pprev, &prev->next); rcu_assign_pointer(hlist_next_rcu(prev), n); if (n->next) - n->next->pprev = &n->next; + WRITE_ONCE(n->next->pprev, &n->next); } #define __hlist_for_each_rcu(pos, head) \ @@ -636,7 +646,7 @@ static inline void hlist_add_behind_rcu(struct hlist_node *n, * @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. + * @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() diff --git a/include/linux/rculist_nulls.h b/include/linux/rculist_nulls.h index bc8206a8f30e..409a86bb5f25 100644 --- a/include/linux/rculist_nulls.h +++ b/include/linux/rculist_nulls.h @@ -34,13 +34,21 @@ static inline void hlist_nulls_del_init_rcu(struct hlist_nulls_node *n) { if (!hlist_nulls_unhashed(n)) { __hlist_nulls_del(n); - n->pprev = NULL; + WRITE_ONCE(n->pprev, NULL); } } +/** + * hlist_nulls_first_rcu - returns the first element of the hash list. + * @head: the head of the list. + */ #define hlist_nulls_first_rcu(head) \ (*((struct hlist_nulls_node __rcu __force **)&(head)->first)) +/** + * hlist_nulls_next_rcu - returns the element of the list after @node. + * @node: element of the list. + */ #define hlist_nulls_next_rcu(node) \ (*((struct hlist_nulls_node __rcu __force **)&(node)->next)) @@ -66,7 +74,7 @@ static inline void hlist_nulls_del_init_rcu(struct hlist_nulls_node *n) static inline void hlist_nulls_del_rcu(struct hlist_nulls_node *n) { __hlist_nulls_del(n); - n->pprev = LIST_POISON2; + WRITE_ONCE(n->pprev, LIST_POISON2); } /** @@ -94,17 +102,17 @@ static inline void hlist_nulls_add_head_rcu(struct hlist_nulls_node *n, struct hlist_nulls_node *first = h->first; n->next = first; - n->pprev = &h->first; + WRITE_ONCE(n->pprev, &h->first); rcu_assign_pointer(hlist_nulls_first_rcu(h), n); if (!is_a_nulls(first)) - first->pprev = &n->next; + WRITE_ONCE(first->pprev, &n->next); } /** * hlist_nulls_for_each_entry_rcu - iterate over rcu list of given type * @tpos: the type * to use as a loop cursor. * @pos: the &struct hlist_nulls_node to use as a loop cursor. - * @head: the head for your list. + * @head: the head of the list. * @member: the name of the hlist_nulls_node within the struct. * * The barrier() is needed to make sure compiler doesn't cache first element [1], @@ -124,7 +132,7 @@ static inline void hlist_nulls_add_head_rcu(struct hlist_nulls_node *n, * iterate over list of given type safe against removal of list entry * @tpos: the type * to use as a loop cursor. * @pos: the &struct hlist_nulls_node to use as a loop cursor. - * @head: the head for your list. + * @head: the head of the list. * @member: the name of the hlist_nulls_node within the struct. */ #define hlist_nulls_for_each_entry_safe(tpos, pos, head, member) \ diff --git a/include/linux/rcupdate.h b/include/linux/rcupdate.h index 0b7506330c87..2678a37c3169 100644 --- a/include/linux/rcupdate.h +++ b/include/linux/rcupdate.h @@ -154,7 +154,7 @@ static inline void exit_tasks_rcu_finish(void) { } * * This macro resembles cond_resched(), except that it is defined to * report potential quiescent states to RCU-tasks even if the cond_resched() - * machinery were to be shut off, as some advocate for PREEMPT kernels. + * machinery were to be shut off, as some advocate for PREEMPTION kernels. */ #define cond_resched_tasks_rcu_qs() \ do { \ @@ -167,7 +167,7 @@ do { \ * TREE_RCU and rcu_barrier_() primitives in TINY_RCU. */ -#if defined(CONFIG_TREE_RCU) || defined(CONFIG_PREEMPT_RCU) +#if defined(CONFIG_TREE_RCU) #include <linux/rcutree.h> #elif defined(CONFIG_TINY_RCU) #include <linux/rcutiny.h> @@ -401,22 +401,6 @@ do { \ }) /** - * rcu_swap_protected() - swap an RCU and a regular pointer - * @rcu_ptr: RCU pointer - * @ptr: regular pointer - * @c: the conditions under which the dereference will take place - * - * Perform swap(@rcu_ptr, @ptr) where @rcu_ptr is an RCU-annotated pointer and - * @c is the argument that is passed to the rcu_dereference_protected() call - * used to read that pointer. - */ -#define rcu_swap_protected(rcu_ptr, ptr, c) do { \ - typeof(ptr) __tmp = rcu_dereference_protected((rcu_ptr), (c)); \ - rcu_assign_pointer((rcu_ptr), (ptr)); \ - (ptr) = __tmp; \ -} while (0) - -/** * rcu_access_pointer() - fetch RCU pointer with no dereferencing * @p: The pointer to read * @@ -598,10 +582,10 @@ do { \ * * You can avoid reading and understanding the next paragraph by * following this rule: don't put anything in an rcu_read_lock() RCU - * read-side critical section that would block in a !PREEMPT kernel. + * read-side critical section that would block in a !PREEMPTION kernel. * But if you want the full story, read on! * - * In non-preemptible RCU implementations (TREE_RCU and TINY_RCU), + * In non-preemptible RCU implementations (pure TREE_RCU and TINY_RCU), * it is illegal to block while in an RCU read-side critical section. * In preemptible RCU implementations (PREEMPT_RCU) in CONFIG_PREEMPTION * kernel builds, RCU read-side critical sections may be preempted, @@ -912,4 +896,8 @@ rcu_head_after_call_rcu(struct rcu_head *rhp, rcu_callback_t f) return false; } +/* kernel/ksysfs.c definitions */ +extern int rcu_expedited; +extern int rcu_normal; + #endif /* __LINUX_RCUPDATE_H */ diff --git a/include/linux/rcutiny.h b/include/linux/rcutiny.h index 37b6f0c2b79d..b2b2dc990da9 100644 --- a/include/linux/rcutiny.h +++ b/include/linux/rcutiny.h @@ -85,6 +85,7 @@ static inline void rcu_scheduler_starting(void) { } static inline void rcu_end_inkernel_boot(void) { } static inline bool rcu_is_watching(void) { return true; } static inline void rcu_momentary_dyntick_idle(void) { } +static inline void kfree_rcu_scheduler_running(void) { } /* Avoid RCU read-side critical sections leaking across. */ static inline void rcu_all_qs(void) { barrier(); } diff --git a/include/linux/rcutree.h b/include/linux/rcutree.h index c5147de885ec..2f787b9029d1 100644 --- a/include/linux/rcutree.h +++ b/include/linux/rcutree.h @@ -38,6 +38,7 @@ void kfree_call_rcu(struct rcu_head *head, rcu_callback_t func); void rcu_barrier(void); bool rcu_eqs_special_set(int cpu); void rcu_momentary_dyntick_idle(void); +void kfree_rcu_scheduler_running(void); unsigned long get_state_synchronize_rcu(void); void cond_synchronize_rcu(unsigned long oldstate); |