X-Git-Url: http://git.ozlabs.org/?p=ccan;a=blobdiff_plain;f=ccan%2Flist%2Flist.h;h=a6b00385984c52ce9ab3a614e351437616f69b8e;hp=983675b81f9d53877fd5d0dfaa56abc1d742a641;hb=HEAD;hpb=3d74240c155b68ae0d59a5942048aa1db3e29b01 diff --git a/ccan/list/list.h b/ccan/list/list.h index 983675b8..a15321c5 100644 --- a/ccan/list/list.h +++ b/ccan/list/list.h @@ -95,8 +95,8 @@ struct list_node *list_check_node(const struct list_node *n, #define list_debug(h, loc) list_check((h), loc) #define list_debug_node(n, loc) list_check_node((n), loc) #else -#define list_debug(h, loc) (h) -#define list_debug_node(n, loc) (n) +#define list_debug(h, loc) ((void)loc, h) +#define list_debug_node(n, loc) ((void)loc, n) #endif /** @@ -111,7 +111,7 @@ struct list_node *list_check_node(const struct list_node *n, * Example: * static struct list_head my_list = LIST_HEAD_INIT(my_list); */ -#define LIST_HEAD_INIT(name) { { &name.n, &name.n } } +#define LIST_HEAD_INIT(name) { { &(name).n, &(name).n } } /** * LIST_HEAD - define and initialize an empty list_head @@ -291,6 +291,21 @@ static inline bool list_empty_nodebug(const struct list_head *h) } #endif +/** + * list_empty_nocheck - is a list empty? + * @h: the list_head + * + * If the list is empty, returns true. This doesn't perform any + * debug check for list consistency, so it can be called without + * locks, racing with the list being modified. This is ok for + * checks where an incorrect result is not an issue (optimized + * bail out path for example). + */ +static inline bool list_empty_nocheck(const struct list_head *h) +{ + return h->n.next == &h->n; +} + /** * list_del - delete an entry from an (unknown) linked list. * @n: the list_node to delete from the list. @@ -522,9 +537,29 @@ static inline const void *list_tail_(const struct list_head *h, size_t off) * printf("Name: %s\n", child->name); */ #define list_for_each_rev(h, i, member) \ - for (i = container_of_var(list_debug(h, LIST_LOC)->n.prev, i, member); \ - &i->member != &(h)->n; \ - i = container_of_var(i->member.prev, i, member)) + list_for_each_rev_off(h, i, list_off_var_(i, member)) + +/** + * list_for_each_rev_safe - iterate through a list backwards, + * maybe during deletion + * @h: the list_head + * @i: the structure containing the list_node + * @nxt: the structure containing the list_node + * @member: the list_node member of the structure + * + * This is a convenient wrapper to iterate @i over the entire list backwards. + * It's a for loop, so you can break and continue as normal. The extra + * variable * @nxt is used to hold the next element, so you can delete @i + * from the list. + * + * Example: + * struct child *next; + * list_for_each_rev_safe(&parent->children, child, next, list) { + * printf("Name: %s\n", child->name); + * } + */ +#define list_for_each_rev_safe(h, i, nxt, member) \ + list_for_each_rev_safe_off(h, i, nxt, list_off_var_(i, member)) /** * list_for_each_safe - iterate through a list, maybe during deletion @@ -538,7 +573,6 @@ static inline const void *list_tail_(const struct list_head *h, size_t off) * @nxt is used to hold the next element, so you can delete @i from the list. * * Example: - * struct child *next; * list_for_each_safe(&parent->children, child, next, list) { * list_del(&child->list); * parent->num_children--; @@ -653,10 +687,28 @@ static inline void list_prepend_list_(struct list_head *to, list_head_init(from); } +/* internal macros, do not use directly */ +#define list_for_each_off_dir_(h, i, off, dir) \ + for (i = list_node_to_off_(list_debug(h, LIST_LOC)->n.dir, \ + (off)); \ + list_node_from_off_((void *)i, (off)) != &(h)->n; \ + i = list_node_to_off_(list_node_from_off_((void *)i, (off))->dir, \ + (off))) + +#define list_for_each_safe_off_dir_(h, i, nxt, off, dir) \ + for (i = list_node_to_off_(list_debug(h, LIST_LOC)->n.dir, \ + (off)), \ + nxt = list_node_to_off_(list_node_from_off_(i, (off))->dir, \ + (off)); \ + list_node_from_off_(i, (off)) != &(h)->n; \ + i = nxt, \ + nxt = list_node_to_off_(list_node_from_off_(i, (off))->dir, \ + (off))) + /** * list_for_each_off - iterate through a list of memory regions. * @h: the list_head - * @i: the pointer to a memory region wich contains list node data. + * @i: the pointer to a memory region which contains list node data. * @off: offset(relative to @i) at which list node data resides. * * This is a low-level wrapper to iterate @i over the entire list, used to @@ -664,12 +716,12 @@ static inline void list_prepend_list_(struct list_head *to, * so you can break and continue as normal. * * WARNING! Being the low-level macro that it is, this wrapper doesn't know - * nor care about the type of @i. The only assumtion made is that @i points + * nor care about the type of @i. The only assumption made is that @i points * to a chunk of memory that at some @offset, relative to @i, contains a - * properly filled `struct node_list' which in turn contains pointers to - * memory chunks and it's turtles all the way down. Whith all that in mind + * properly filled `struct list_node' which in turn contains pointers to + * memory chunks and it's turtles all the way down. With all that in mind * remember that given the wrong pointer/offset couple this macro will - * happilly churn all you memory untill SEGFAULT stops it, in other words + * happily churn all you memory until SEGFAULT stops it, in other words * caveat emptor. * * It is worth mentioning that one of legitimate use-cases for that wrapper @@ -683,17 +735,24 @@ static inline void list_prepend_list_(struct list_head *to, * printf("Name: %s\n", child->name); */ #define list_for_each_off(h, i, off) \ - for (i = list_node_to_off_(list_debug(h, LIST_LOC)->n.next, \ - (off)); \ - list_node_from_off_((void *)i, (off)) != &(h)->n; \ - i = list_node_to_off_(list_node_from_off_((void *)i, (off))->next, \ - (off))) + list_for_each_off_dir_((h),(i),(off),next) + +/** + * list_for_each_rev_off - iterate through a list of memory regions backwards + * @h: the list_head + * @i: the pointer to a memory region which contains list node data. + * @off: offset(relative to @i) at which list node data resides. + * + * See list_for_each_off for details + */ +#define list_for_each_rev_off(h, i, off) \ + list_for_each_off_dir_((h),(i),(off),prev) /** * list_for_each_safe_off - iterate through a list of memory regions, maybe * during deletion * @h: the list_head - * @i: the pointer to a memory region wich contains list node data. + * @i: the pointer to a memory region which contains list node data. * @nxt: the structure containing the list_node * @off: offset(relative to @i) at which list node data resides. * @@ -706,15 +765,26 @@ static inline void list_prepend_list_(struct list_head *to, * printf("Name: %s\n", child->name); */ #define list_for_each_safe_off(h, i, nxt, off) \ - for (i = list_node_to_off_(list_debug(h, LIST_LOC)->n.next, \ - (off)), \ - nxt = list_node_to_off_(list_node_from_off_(i, (off))->next, \ - (off)); \ - list_node_from_off_(i, (off)) != &(h)->n; \ - i = nxt, \ - nxt = list_node_to_off_(list_node_from_off_(i, (off))->next, \ - (off))) + list_for_each_safe_off_dir_((h),(i),(nxt),(off),next) +/** + * list_for_each_rev_safe_off - iterate backwards through a list of + * memory regions, maybe during deletion + * @h: the list_head + * @i: the pointer to a memory region which contains list node data. + * @nxt: the structure containing the list_node + * @off: offset(relative to @i) at which list node data resides. + * + * For details see `list_for_each_rev_off' and `list_for_each_rev_safe' + * descriptions. + * + * Example: + * list_for_each_rev_safe_off(&parent->children, child, + * next, offsetof(struct child, list)) + * printf("Name: %s\n", child->name); + */ +#define list_for_each_rev_safe_off(h, i, nxt, off) \ + list_for_each_safe_off_dir_((h),(i),(nxt),(off),prev) /* Other -off variants. */ #define list_entry_off(n, type, off) \