From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from metis.ext.pengutronix.de ([2001:67c:670:201:290:27ff:fe1d:cc33]) by bombadil.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1jkiCa-0007Jw-16 for barebox@lists.infradead.org; Mon, 15 Jun 2020 06:02:41 +0000 From: Sascha Hauer Date: Mon, 15 Jun 2020 08:02:19 +0200 Message-Id: <20200615060229.7533-2-s.hauer@pengutronix.de> In-Reply-To: <20200615060229.7533-1-s.hauer@pengutronix.de> References: <20200615060229.7533-1-s.hauer@pengutronix.de> MIME-Version: 1.0 List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "barebox" Errors-To: barebox-bounces+u.kleine-koenig=pengutronix.de@lists.infradead.org Subject: [PATCH 01/11] update list.h from Linux-5.7 To: Barebox List This updates include/linux/list.h from Linux-5.7. Signed-off-by: Sascha Hauer --- include/linux/compiler.h | 1 - include/linux/list.h | 700 ++++++++++++++++++++++++++++++--------- include/linux/poison.h | 26 ++ include/linux/types.h | 12 + 4 files changed, 581 insertions(+), 158 deletions(-) create mode 100644 include/linux/poison.h diff --git a/include/linux/compiler.h b/include/linux/compiler.h index f597c7abae..f61a458414 100644 --- a/include/linux/compiler.h +++ b/include/linux/compiler.h @@ -250,7 +250,6 @@ static __always_inline void __write_once_size(volatile void *p, void *res, int s __read_once_size(&(x), __u.__c, sizeof(x)); \ else \ __read_once_size_nocheck(&(x), __u.__c, sizeof(x)); \ - smp_read_barrier_depends(); /* Enforce dependency ordering from x */ \ __u.__val; \ }) #define READ_ONCE(x) __READ_ONCE(x, 1) diff --git a/include/linux/list.h b/include/linux/list.h index af5edc9a76..1341806b59 100644 --- a/include/linux/list.h +++ b/include/linux/list.h @@ -1,7 +1,11 @@ +/* SPDX-License-Identifier: GPL-2.0 */ #ifndef _LINUX_LIST_H #define _LINUX_LIST_H -#include /* for NULL */ +#include +#include +#include +#include #include /* @@ -14,46 +18,60 @@ * using the generic single-entry routines. */ -#define LIST_POISON1 ((void *) 0x00100100) -#define LIST_POISON2 ((void *) 0x00200200) -static inline void prefetch(const void *x) {;} - -struct list_head { - struct list_head *next, *prev; -}; - #define LIST_HEAD_INIT(name) { &(name), &(name) } #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) { - list->next = list; + WRITE_ONCE(list->next, list); list->prev = list; } +#ifdef CONFIG_DEBUG_LIST +extern bool __list_add_valid(struct list_head *new, + struct list_head *prev, + struct list_head *next); +extern bool __list_del_entry_valid(struct list_head *entry); +#else +static inline bool __list_add_valid(struct list_head *new, + struct list_head *prev, + struct list_head *next) +{ + return true; +} +static inline bool __list_del_entry_valid(struct list_head *entry) +{ + return true; +} +#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! */ -#ifndef CONFIG_DEBUG_LIST static inline void __list_add(struct list_head *new, struct list_head *prev, struct list_head *next) { + if (!__list_add_valid(new, prev, next)) + return; + next->prev = new; new->next = next; new->prev = prev; - prev->next = new; + WRITE_ONCE(prev->next, new); } -#else -extern void __list_add(struct list_head *new, - struct list_head *prev, - struct list_head *next); -#endif /** * list_add - add a new entry @@ -63,14 +81,10 @@ extern void __list_add(struct list_head *new, * Insert a new entry after the specified head. * This is good for implementing stacks. */ -#ifndef CONFIG_DEBUG_LIST static inline void list_add(struct list_head *new, struct list_head *head) { __list_add(new, head, head->next); } -#else -extern void list_add(struct list_head *new, struct list_head *head); -#endif /** @@ -96,7 +110,29 @@ static inline void list_add_tail(struct list_head *new, struct list_head *head) static inline void __list_del(struct list_head * prev, struct list_head * next) { next->prev = prev; - prev->next = next; + WRITE_ONCE(prev->next, next); +} + +/* + * Delete a list entry and clear the 'prev' pointer. + * + * This is a special-purpose list clearing method used in the networking code + * for lists allocated as per-cpu, where we don't want to incur the extra + * WRITE_ONCE() overhead of a regular list_del_init(). The code that uses this + * needs to check the node 'prev' pointer instead of calling list_empty(). + */ +static inline void __list_del_clearprev(struct list_head *entry) +{ + __list_del(entry->prev, entry->next); + entry->prev = NULL; +} + +static inline void __list_del_entry(struct list_head *entry) +{ + if (!__list_del_entry_valid(entry)) + return; + + __list_del(entry->prev, entry->next); } /** @@ -105,16 +141,12 @@ static inline void __list_del(struct list_head * prev, struct list_head * next) * Note: list_empty() on entry does not return true after this, the entry is * in an undefined state. */ -#ifndef CONFIG_DEBUG_LIST static inline void list_del(struct list_head *entry) { - __list_del(entry->prev, entry->next); + __list_del_entry(entry); entry->next = LIST_POISON1; entry->prev = LIST_POISON2; } -#else -extern void list_del(struct list_head *entry); -#endif /** * list_replace - replace old entry by new one @@ -132,20 +164,44 @@ 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); } +/** + * list_swap - replace entry1 with entry2 and re-add entry1 at entry2's position + * @entry1: the location to place entry2 + * @entry2: the location to place entry1 + */ +static inline void list_swap(struct list_head *entry1, + struct list_head *entry2) +{ + struct list_head *pos = entry2->prev; + + list_del(entry2); + list_replace(entry1, entry2); + if (pos == entry1) + pos = entry2; + list_add(entry1, pos); +} + /** * list_del_init - deletes entry from list and reinitialize it. * @entry: the element to delete from the list. */ static inline void list_del_init(struct list_head *entry) { - __list_del(entry->prev, entry->next); + __list_del_entry(entry); INIT_LIST_HEAD(entry); } @@ -156,7 +212,7 @@ static inline void list_del_init(struct list_head *entry) */ static inline void list_move(struct list_head *list, struct list_head *head) { - __list_del(list->prev, list->next); + __list_del_entry(list); list_add(list, head); } @@ -168,10 +224,44 @@ static inline void list_move(struct list_head *list, struct list_head *head) static inline void list_move_tail(struct list_head *list, struct list_head *head) { - __list_del(list->prev, list->next); + __list_del_entry(list); list_add_tail(list, head); } +/** + * list_bulk_move_tail - move a subsection of a list to its tail + * @head: the head that will follow our entry + * @first: first entry to move + * @last: last entry to move, can be the same as first + * + * Move all entries between @first and including @last before @head. + * All three entries must belong to the same linked list. + */ +static inline void list_bulk_move_tail(struct list_head *head, + struct list_head *first, + struct list_head *last) +{ + first->prev->next = last->next; + last->next->prev = first->prev; + + head->prev->next = first; + first->prev = head->prev; + + last->next = head; + head->prev = last; +} + +/** + * list_is_first -- tests whether @list is the first entry in list @head + * @list: the entry to test + * @head: the head of the list + */ +static inline int list_is_first(const struct list_head *list, + const struct list_head *head) +{ + return list->prev == head; +} + /** * list_is_last - tests whether @list is the last entry in list @head * @list: the entry to test @@ -189,7 +279,7 @@ static inline int list_is_last(const struct list_head *list, */ static inline int list_empty(const struct list_head *head) { - return head->next == head; + return READ_ONCE(head->next) == head; } /** @@ -211,6 +301,38 @@ static inline int list_empty_careful(const struct list_head *head) return (next == head) && (next == head->prev); } +/** + * list_rotate_left - rotate the list to the left + * @head: the head of the list + */ +static inline void list_rotate_left(struct list_head *head) +{ + struct list_head *first; + + if (!list_empty(head)) { + first = head->next; + list_move_tail(first, head); + } +} + +/** + * list_rotate_to_front() - Rotate list to specific item. + * @list: The desired new front of the list. + * @head: The head of the list. + * + * Rotates list so that @list becomes the new front of the list. + */ +static inline void list_rotate_to_front(struct list_head *list, + struct list_head *head) +{ + /* + * Deletes the list head from the list denoted by @head and + * places it as the tail of @list, this effectively rotates the + * list so that @list is at the front. + */ + list_move_tail(head, list); +} + /** * list_is_singular - tests whether a list has just one entry. * @head: the list to test. @@ -220,29 +342,112 @@ static inline int list_is_singular(const struct list_head *head) return !list_empty(head) && (head->next == head->prev); } -static inline void __list_splice(struct list_head *list, - struct list_head *head) +static inline void __list_cut_position(struct list_head *list, + struct list_head *head, struct list_head *entry) +{ + struct list_head *new_first = entry->next; + list->next = head->next; + list->next->prev = list; + list->prev = entry; + entry->next = list; + head->next = new_first; + new_first->prev = head; +} + +/** + * list_cut_position - cut a list into two + * @list: a new list to add all removed entries + * @head: a list with entries + * @entry: an entry within head, could be the head itself + * and if so we won't cut the list + * + * This helper moves the initial part of @head, up to and + * including @entry, from @head to @list. You should + * pass on @entry an element you know is on @head. @list + * should be an empty list or a list you do not care about + * losing its data. + * + */ +static inline void list_cut_position(struct list_head *list, + struct list_head *head, struct list_head *entry) +{ + if (list_empty(head)) + return; + if (list_is_singular(head) && + (head->next != entry && head != entry)) + return; + if (entry == head) + INIT_LIST_HEAD(list); + else + __list_cut_position(list, head, entry); +} + +/** + * list_cut_before - cut a list into two, before given entry + * @list: a new list to add all removed entries + * @head: a list with entries + * @entry: an entry within head, could be the head itself + * + * This helper moves the initial part of @head, up to but + * excluding @entry, from @head to @list. You should pass + * in @entry an element you know is on @head. @list should + * be an empty list or a list you do not care about losing + * its data. + * If @entry == @head, all entries on @head are moved to + * @list. + */ +static inline void list_cut_before(struct list_head *list, + struct list_head *head, + struct list_head *entry) +{ + if (head->next == entry) { + INIT_LIST_HEAD(list); + return; + } + list->next = head->next; + list->next->prev = list; + list->prev = entry->prev; + list->prev->next = list; + head->next = entry; + entry->prev = head; +} + +static inline void __list_splice(const struct list_head *list, + struct list_head *prev, + struct list_head *next) { struct list_head *first = list->next; struct list_head *last = list->prev; - struct list_head *at = head->next; - first->prev = head; - head->next = first; + first->prev = prev; + prev->next = first; - last->next = at; - at->prev = last; + last->next = next; + next->prev = last; +} + +/** + * list_splice - join two lists, this is designed for stacks + * @list: the new list to add. + * @head: the place to add it in the first list. + */ +static inline void list_splice(const struct list_head *list, + struct list_head *head) +{ + if (!list_empty(list)) + __list_splice(list, head, head->next); } /** - * list_splice - join two lists + * list_splice_tail - join two lists, each list being a queue * @list: the new list to add. * @head: the place to add it in the first list. */ -static inline void list_splice(struct list_head *list, struct list_head *head) +static inline void list_splice_tail(struct list_head *list, + struct list_head *head) { if (!list_empty(list)) - __list_splice(list, head); + __list_splice(list, head->prev, head); } /** @@ -256,7 +461,24 @@ static inline void list_splice_init(struct list_head *list, struct list_head *head) { if (!list_empty(list)) { - __list_splice(list, head); + __list_splice(list, head, head->next); + INIT_LIST_HEAD(list); + } +} + +/** + * list_splice_tail_init - join two lists and reinitialise the emptied list + * @list: the new list to add. + * @head: the place to add it in the first list. + * + * Each of the lists is a queue. + * The list at @list is reinitialised + */ +static inline void list_splice_tail_init(struct list_head *list, + struct list_head *head) +{ + if (!list_empty(list)) { + __list_splice(list, head->prev, head); INIT_LIST_HEAD(list); } } @@ -265,7 +487,7 @@ static inline void list_splice_init(struct list_head *list, * list_entry - 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_struct within the struct. + * @member: the name of the list_head within the struct. */ #define list_entry(ptr, type, member) \ container_of(ptr, type, member) @@ -274,7 +496,7 @@ static inline void list_splice_init(struct list_head *list, * list_first_entry - 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_struct within the struct. + * @member: the name of the list_head within the struct. * * Note, that list is expected to be not empty. */ @@ -283,25 +505,44 @@ static inline void list_splice_init(struct list_head *list, /** * list_last_entry - get the last element from a list - * @head: the list head to take the element from. - * @type: the type of the struct this is embedded in. - * @member: the name of the list_struct within the struct. + * @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 list is expected to be not empty. */ -#define list_last_entry(head, type, member) \ - list_entry((head)->prev, type, member) +#define list_last_entry(ptr, type, member) \ + list_entry((ptr)->prev, type, member) /** * list_first_entry_or_null - 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_struct within the struct. + * @member: the name of the list_head within the struct. * * Note that if the list is empty, it returns NULL. */ -#define list_first_entry_or_null(ptr, type, member) \ - (!list_empty(ptr) ? list_first_entry(ptr, type, member) : NULL) +#define list_first_entry_or_null(ptr, type, member) ({ \ + struct list_head *head__ = (ptr); \ + struct list_head *pos__ = READ_ONCE(head__->next); \ + pos__ != head__ ? list_entry(pos__, type, member) : NULL; \ +}) + +/** + * list_next_entry - get the next element in list + * @pos: the type * to cursor + * @member: the name of the list_head within the struct. + */ +#define list_next_entry(pos, member) \ + list_entry((pos)->member.next, typeof(*(pos)), member) + +/** + * list_prev_entry - get the prev element in list + * @pos: the type * to cursor + * @member: the name of the list_head within the struct. + */ +#define list_prev_entry(pos, member) \ + list_entry((pos)->member.prev, typeof(*(pos)), member) /** * list_for_each - iterate over a list @@ -309,21 +550,17 @@ static inline void list_splice_init(struct list_head *list, * @head: the head for your list. */ #define list_for_each(pos, head) \ - for (pos = (head)->next; prefetch(pos->next), pos != (head); \ - pos = pos->next) + for (pos = (head)->next; pos != (head); pos = pos->next) /** - * __list_for_each - iterate over a list + * list_for_each_continue - continue iteration over a list * @pos: the &struct list_head to use as a loop cursor. * @head: the head for your list. * - * This variant differs from list_for_each() in that it's the - * simplest possible list iteration code, no prefetching is done. - * Use this for code that knows the list to be very short (empty - * or 1 entry) most of the time. + * Continue to iterate over a list, continuing after the current position. */ -#define __list_for_each(pos, head) \ - for (pos = (head)->next; pos != (head); pos = pos->next) +#define list_for_each_continue(pos, head) \ + for (pos = pos->next; pos != (head); pos = pos->next) /** * list_for_each_prev - iterate over a list backwards @@ -331,8 +568,7 @@ static inline void list_splice_init(struct list_head *list, * @head: the head for your list. */ #define list_for_each_prev(pos, head) \ - for (pos = (head)->prev; prefetch(pos->prev), pos != (head); \ - pos = pos->prev) + for (pos = (head)->prev; pos != (head); pos = pos->prev) /** * list_for_each_safe - iterate over a list safe against removal of list entry @@ -344,33 +580,44 @@ static inline void list_splice_init(struct list_head *list, for (pos = (head)->next, n = pos->next; pos != (head); \ pos = n, n = pos->next) +/** + * list_for_each_prev_safe - iterate over a list backwards safe against removal of list entry + * @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. + */ +#define list_for_each_prev_safe(pos, n, head) \ + for (pos = (head)->prev, n = pos->prev; \ + pos != (head); \ + pos = n, n = pos->prev) + /** * list_for_each_entry - iterate 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. + * @member: the name of the list_head within the struct. */ #define list_for_each_entry(pos, head, member) \ - for (pos = list_entry((head)->next, typeof(*pos), member); \ - prefetch(pos->member.next), &pos->member != (head); \ - pos = list_entry(pos->member.next, typeof(*pos), member)) + for (pos = list_first_entry(head, typeof(*pos), member); \ + &pos->member != (head); \ + pos = list_next_entry(pos, member)) /** * list_for_each_entry_reverse - iterate backwards 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. + * @member: the name of the list_head within the struct. */ #define list_for_each_entry_reverse(pos, head, member) \ - for (pos = list_entry((head)->prev, typeof(*pos), member); \ - prefetch(pos->member.prev), &pos->member != (head); \ - pos = list_entry(pos->member.prev, typeof(*pos), member)) + for (pos = list_last_entry(head, typeof(*pos), member); \ + &pos->member != (head); \ + pos = list_prev_entry(pos, member)) /** * list_prepare_entry - prepare a pos entry for use in list_for_each_entry_continue() * @pos: the type * to use as a start point * @head: the head of the list - * @member: the name of the list_struct within the struct. + * @member: the name of the list_head within the struct. * * Prepares a pos entry for use as a start point in list_for_each_entry_continue(). */ @@ -381,87 +628,129 @@ static inline void list_splice_init(struct list_head *list, * list_for_each_entry_continue - 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. + * @member: the name of the list_head within the struct. * * Continue to iterate over list of given type, continuing after * the current position. */ #define list_for_each_entry_continue(pos, head, member) \ - for (pos = list_entry(pos->member.next, typeof(*pos), member); \ - prefetch(pos->member.next), &pos->member != (head); \ - pos = list_entry(pos->member.next, typeof(*pos), member)) + for (pos = list_next_entry(pos, member); \ + &pos->member != (head); \ + pos = list_next_entry(pos, member)) + +/** + * list_for_each_entry_continue_reverse - iterate backwards from the given point + * @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. + * + * Start to iterate over list of given type backwards, continuing after + * the current position. + */ +#define list_for_each_entry_continue_reverse(pos, head, member) \ + for (pos = list_prev_entry(pos, member); \ + &pos->member != (head); \ + pos = list_prev_entry(pos, member)) /** * list_for_each_entry_from - iterate over list of given type from the current point * @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. + * @member: the name of the list_head within the struct. * * Iterate over list of given type, continuing from current position. */ #define list_for_each_entry_from(pos, head, member) \ - for (; prefetch(pos->member.next), &pos->member != (head); \ - pos = list_entry(pos->member.next, typeof(*pos), member)) + for (; &pos->member != (head); \ + pos = list_next_entry(pos, member)) + +/** + * list_for_each_entry_from_reverse - iterate backwards over list of given type + * from the current point + * @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. + * + * Iterate backwards over list of given type, continuing from current position. + */ +#define list_for_each_entry_from_reverse(pos, head, member) \ + for (; &pos->member != (head); \ + pos = list_prev_entry(pos, member)) /** * list_for_each_entry_safe - iterate over list of given type safe against removal of list entry * @pos: the type * to use as a loop cursor. * @n: another type * to use as temporary storage * @head: the head for your list. - * @member: the name of the list_struct within the struct. + * @member: the name of the list_head within the struct. */ #define list_for_each_entry_safe(pos, n, head, member) \ - for (pos = list_entry((head)->next, typeof(*pos), member), \ - n = list_entry(pos->member.next, typeof(*pos), member); \ + for (pos = list_first_entry(head, typeof(*pos), member), \ + n = list_next_entry(pos, member); \ &pos->member != (head); \ - pos = n, n = list_entry(n->member.next, typeof(*n), member)) + pos = n, n = list_next_entry(n, member)) /** - * list_for_each_entry_safe_continue + * list_for_each_entry_safe_continue - continue list iteration safe against removal * @pos: the type * to use as a loop cursor. * @n: another type * to use as temporary storage * @head: the head for your list. - * @member: the name of the list_struct within the struct. + * @member: the name of the list_head within the struct. * * Iterate over list of given type, continuing after current point, * safe against removal of list entry. */ #define list_for_each_entry_safe_continue(pos, n, head, member) \ - for (pos = list_entry(pos->member.next, typeof(*pos), member), \ - n = list_entry(pos->member.next, typeof(*pos), member); \ + for (pos = list_next_entry(pos, member), \ + n = list_next_entry(pos, member); \ &pos->member != (head); \ - pos = n, n = list_entry(n->member.next, typeof(*n), member)) + pos = n, n = list_next_entry(n, member)) /** - * list_for_each_entry_safe_from + * list_for_each_entry_safe_from - iterate over list from current point safe against removal * @pos: the type * to use as a loop cursor. * @n: another type * to use as temporary storage * @head: the head for your list. - * @member: the name of the list_struct within the struct. + * @member: the name of the list_head within the struct. * * Iterate over list of given type from current point, safe against * removal of list entry. */ #define list_for_each_entry_safe_from(pos, n, head, member) \ - for (n = list_entry(pos->member.next, typeof(*pos), member); \ + for (n = list_next_entry(pos, member); \ &pos->member != (head); \ - pos = n, n = list_entry(n->member.next, typeof(*n), member)) + pos = n, n = list_next_entry(n, member)) /** - * list_for_each_entry_safe_reverse + * list_for_each_entry_safe_reverse - iterate backwards over list safe against removal * @pos: the type * to use as a loop cursor. * @n: another type * to use as temporary storage * @head: the head for your list. - * @member: the name of the list_struct within the struct. + * @member: the name of the list_head within the struct. * * Iterate backwards over list of given type, safe against removal * of list entry. */ #define list_for_each_entry_safe_reverse(pos, n, head, member) \ - for (pos = list_entry((head)->prev, typeof(*pos), member), \ - n = list_entry(pos->member.prev, typeof(*pos), member); \ + for (pos = list_last_entry(head, typeof(*pos), member), \ + n = list_prev_entry(pos, member); \ &pos->member != (head); \ - pos = n, n = list_entry(n->member.prev, typeof(*n), member)) + pos = n, n = list_prev_entry(n, member)) + +/** + * list_safe_reset_next - reset a stale list_for_each_entry_safe loop + * @pos: the loop cursor used in the list_for_each_entry_safe loop + * @n: temporary storage used in list_for_each_entry_safe + * @member: the name of the list_head within the struct. + * + * list_safe_reset_next is not safe to use in general if the list may be + * modified concurrently (eg. the lock is dropped in the loop body). An + * exception to this is if the cursor element (pos) is pinned in the list, + * and list_safe_reset_next is called after re-taking the lock and before + * completing the current iteration of the loop body. + */ +#define list_safe_reset_next(pos, n, member) \ + n = list_next_entry(pos, member) /** * list_add_sort - add a new entry to a sorted list @@ -473,7 +762,7 @@ static inline void list_splice_init(struct list_head *list, * This is useful for implementing queues. */ static inline void list_add_sort(struct list_head *new, struct list_head *head, - int (*compare)(struct list_head *a, struct list_head *b)) + int (*compare)(struct list_head *a, struct list_head *b)) { struct list_head *pos, *insert = head; @@ -494,14 +783,6 @@ static inline void list_add_sort(struct list_head *new, struct list_head *head, * You lose the ability to access the tail in O(1). */ -struct hlist_head { - struct hlist_node *first; -}; - -struct hlist_node { - struct hlist_node *next, **pprev; -}; - #define HLIST_HEAD_INIT { .first = NULL } #define HLIST_HEAD(name) struct hlist_head name = { .first = NULL } #define INIT_HLIST_HEAD(ptr) ((ptr)->first = NULL) @@ -511,25 +792,58 @@ 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 !h->first; + return !READ_ONCE(h->first); } static inline void __hlist_del(struct hlist_node *n) { struct hlist_node *next = n->next; struct hlist_node **pprev = n->pprev; - *pprev = next; + + 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); @@ -537,6 +851,12 @@ 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)) { @@ -545,95 +865,161 @@ 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; - h->first = n; - n->pprev = &h->first; + WRITE_ONCE(first->pprev, &n->next); + WRITE_ONCE(h->first, n); + 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) +{ + 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->pprev = next->pprev; - n->next = next; - next->pprev = &n->next; - *(n->pprev) = n; + WRITE_ONCE(n->next, prev->next); + WRITE_ONCE(prev->next, n); + WRITE_ONCE(n->pprev, &prev->next); + + if (n->next) + WRITE_ONCE(n->next->pprev, &n->next); +} + +/** + * 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; } -static inline void hlist_add_after(struct hlist_node *n, - struct hlist_node *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, thus avoiding unnecessary cache misses. + */ +static inline bool +hlist_is_singular_node(struct hlist_node *n, struct hlist_head *h) { - next->next = n->next; - n->next = next; - next->pprev = &n->next; + return !n->next && n->pprev == &h->first; +} - if(next->next) - next->next->pprev = &next->next; +/** + * 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. + */ +static inline void hlist_move_list(struct hlist_head *old, + struct hlist_head *new) +{ + new->first = old->first; + if (new->first) + new->first->pprev = &new->first; + old->first = NULL; } #define hlist_entry(ptr, type, member) container_of(ptr,type,member) #define hlist_for_each(pos, head) \ - for (pos = (head)->first; pos && ({ prefetch(pos->next); 1; }); \ - pos = pos->next) + for (pos = (head)->first; pos ; pos = pos->next) #define hlist_for_each_safe(pos, n, head) \ for (pos = (head)->first; pos && ({ n = pos->next; 1; }); \ pos = n) +#define hlist_entry_safe(ptr, type, member) \ + ({ typeof(ptr) ____ptr = (ptr); \ + ____ptr ? hlist_entry(____ptr, type, member) : NULL; \ + }) + /** * hlist_for_each_entry - iterate over list of given type - * @tpos: the type * to use as a loop cursor. - * @pos: the &struct hlist_node to use as a loop cursor. + * @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. */ -#define hlist_for_each_entry(tpos, pos, head, member) \ - for (pos = (head)->first; \ - pos && ({ prefetch(pos->next); 1;}) && \ - ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ - pos = pos->next) +#define hlist_for_each_entry(pos, head, member) \ + for (pos = hlist_entry_safe((head)->first, typeof(*(pos)), member);\ + pos; \ + pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member)) /** * hlist_for_each_entry_continue - 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. + * @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(tpos, pos, member) \ - for (pos = (pos)->next; \ - pos && ({ prefetch(pos->next); 1;}) && \ - ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ - pos = pos->next) +#define hlist_for_each_entry_continue(pos, member) \ + for (pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member);\ + pos; \ + pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member)) /** * hlist_for_each_entry_from - iterate over a hlist continuing from current point - * @tpos: the type * to use as a loop cursor. - * @pos: the &struct hlist_node to use as a loop cursor. + * @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(tpos, pos, member) \ - for (; pos && ({ prefetch(pos->next); 1;}) && \ - ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ - pos = pos->next) +#define hlist_for_each_entry_from(pos, member) \ + for (; pos; \ + pos = hlist_entry_safe((pos)->member.next, typeof(*(pos)), member)) /** * hlist_for_each_entry_safe - 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_node to use as a loop cursor. - * @n: another &struct hlist_node to use as temporary storage + * @pos: the type * to use as a loop cursor. + * @n: a &struct hlist_node to use as temporary storage * @head: the head for your list. * @member: the name of the hlist_node within the struct. */ -#define hlist_for_each_entry_safe(tpos, pos, n, head, member) \ - for (pos = (head)->first; \ - pos && ({ n = pos->next; 1; }) && \ - ({ tpos = hlist_entry(pos, typeof(*tpos), member); 1;}); \ - pos = n) +#define hlist_for_each_entry_safe(pos, n, head, member) \ + for (pos = hlist_entry_safe((head)->first, typeof(*pos), member);\ + pos && ({ n = pos->member.next; 1; }); \ + pos = hlist_entry_safe(n, typeof(*pos), member)) #endif diff --git a/include/linux/poison.h b/include/linux/poison.h new file mode 100644 index 0000000000..b92eb2f95b --- /dev/null +++ b/include/linux/poison.h @@ -0,0 +1,26 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _LINUX_POISON_H +#define _LINUX_POISON_H + +/********** include/linux/list.h **********/ + +/* + * Architectures might want to move the poison pointer offset + * into some well-recognized area such as 0xdead000000000000, + * that is also not mappable by user-space exploits: + */ +#ifdef CONFIG_ILLEGAL_POINTER_VALUE +# define POISON_POINTER_DELTA _AC(CONFIG_ILLEGAL_POINTER_VALUE, UL) +#else +# define POISON_POINTER_DELTA 0 +#endif + +/* + * These are non-NULL pointers that will result in page faults + * under normal circumstances, used to verify that nobody uses + * non-initialized list entries. + */ +#define LIST_POISON1 ((void *) 0x100 + POISON_POINTER_DELTA) +#define LIST_POISON2 ((void *) 0x122 + POISON_POINTER_DELTA) + +#endif diff --git a/include/linux/types.h b/include/linux/types.h index c19d1dc053..fa7684e31e 100644 --- a/include/linux/types.h +++ b/include/linux/types.h @@ -206,4 +206,16 @@ struct ustat { char f_fpack[6]; }; +struct list_head { + struct list_head *next, *prev; +}; + +struct hlist_head { + struct hlist_node *first; +}; + +struct hlist_node { + struct hlist_node *next, **pprev; +}; + #endif /* _LINUX_TYPES_H */ -- 2.27.0 _______________________________________________ barebox mailing list barebox@lists.infradead.org http://lists.infradead.org/mailman/listinfo/barebox