From ed2ff2cba766dfe7976a0113f667c9a0a50dff02 Mon Sep 17 00:00:00 2001 From: Chris Mason Date: Thu, 1 Mar 2007 18:59:40 -0500 Subject: [PATCH] Btrfs: pretend page cache & commit code Signed-off-by: Chris Mason --- fs/btrfs/ctree.c | 66 ++++--- fs/btrfs/ctree.h | 5 + fs/btrfs/disk-io.c | 91 +++++++++- fs/btrfs/disk-io.h | 6 + fs/btrfs/list.h | 418 +++++++++++++++++++++++++++++++++++++++++++++ 5 files changed, 558 insertions(+), 28 deletions(-) create mode 100644 fs/btrfs/list.h diff --git a/fs/btrfs/ctree.c b/fs/btrfs/ctree.c index afa5bc5c7c1a..57fa505fb9f6 100644 --- a/fs/btrfs/ctree.c +++ b/fs/btrfs/ctree.c @@ -250,6 +250,7 @@ static int balance_level(struct ctree_root *root, struct ctree_path *path, tree_block_release(root, mid_buf); /* once for the root ptr */ tree_block_release(root, mid_buf); + clean_tree_block(root, mid_buf); return free_extent(root, blocknr, 1); } parent = &parent_buf->node; @@ -280,6 +281,7 @@ static int balance_level(struct ctree_root *root, struct ctree_path *path, if (right->header.nritems == 0) { u64 blocknr = right_buf->blocknr; tree_block_release(root, right_buf); + clean_tree_block(root, right_buf); right_buf = NULL; right = NULL; wret = del_ptr(root, path, level + 1, pslot + 1); @@ -291,7 +293,7 @@ static int balance_level(struct ctree_root *root, struct ctree_path *path, } else { memcpy(parent->keys + pslot + 1, right->keys, sizeof(struct key)); - wret = write_tree_block(root, parent_buf); + wret = dirty_tree_block(root, parent_buf); if (wret) ret = wret; } @@ -316,6 +318,7 @@ static int balance_level(struct ctree_root *root, struct ctree_path *path, /* we've managed to empty the middle node, drop it */ u64 blocknr = mid_buf->blocknr; tree_block_release(root, mid_buf); + clean_tree_block(root, mid_buf); mid_buf = NULL; mid = NULL; wret = del_ptr(root, path, level + 1, pslot); @@ -327,7 +330,7 @@ static int balance_level(struct ctree_root *root, struct ctree_path *path, } else { /* update the parent key to reflect our changes */ memcpy(parent->keys + pslot, mid->keys, sizeof(struct key)); - wret = write_tree_block(root, parent_buf); + wret = dirty_tree_block(root, parent_buf); if (wret) ret = wret; } @@ -458,7 +461,7 @@ static int fixup_low_keys(struct ctree_root *root, break; t = &path->nodes[i]->node; memcpy(t->keys + tslot, key, sizeof(*key)); - wret = write_tree_block(root, path->nodes[i]); + wret = dirty_tree_block(root, path->nodes[i]); if (wret) ret = wret; if (tslot != 0) @@ -508,11 +511,11 @@ static int push_node_left(struct ctree_root *root, struct tree_buffer *dst_buf, src->header.nritems -= push_items; dst->header.nritems += push_items; - wret = write_tree_block(root, src_buf); + wret = dirty_tree_block(root, src_buf); if (wret < 0) ret = wret; - wret = write_tree_block(root, dst_buf); + wret = dirty_tree_block(root, dst_buf); if (wret < 0) ret = wret; return ret; @@ -566,11 +569,11 @@ static int balance_node_right(struct ctree_root *root, src->header.nritems -= push_items; dst->header.nritems += push_items; - wret = write_tree_block(root, src_buf); + wret = dirty_tree_block(root, src_buf); if (wret < 0) ret = wret; - wret = write_tree_block(root, dst_buf); + wret = dirty_tree_block(root, dst_buf); if (wret < 0) ret = wret; return ret; @@ -612,7 +615,7 @@ static int insert_new_root(struct ctree_root *root, tree_block_release(root, root->node); root->node = t; t->count++; - write_tree_block(root, t); + dirty_tree_block(root, t); path->nodes[level] = t; path->slots[level] = 0; return 0; @@ -652,7 +655,7 @@ static int insert_ptr(struct ctree_root *root, lower->header.nritems++; if (lower->keys[1].objectid == 0) BUG(); - write_tree_block(root, path->nodes[level]); + dirty_tree_block(root, path->nodes[level]); return 0; } @@ -698,10 +701,10 @@ static int split_node(struct ctree_root *root, struct ctree_path *path, c->header.nritems = mid; ret = 0; - wret = write_tree_block(root, t); + wret = dirty_tree_block(root, t); if (wret) ret = wret; - wret = write_tree_block(root, split_buffer); + wret = dirty_tree_block(root, split_buffer); if (wret) ret = wret; wret = insert_ptr(root, path, split->keys, split_buffer->blocknr, @@ -815,11 +818,11 @@ static int push_leaf_right(struct ctree_root *root, struct ctree_path *path, } left->header.nritems -= push_items; - write_tree_block(root, left_buf); - write_tree_block(root, right_buf); + dirty_tree_block(root, left_buf); + dirty_tree_block(root, right_buf); memcpy(upper->node.keys + slot + 1, &right->items[0].key, sizeof(struct key)); - write_tree_block(root, upper); + dirty_tree_block(root, upper); /* then fixup the leaf pointer in the path */ if (path->slots[0] >= left->header.nritems) { path->slots[0] -= left->header.nritems; @@ -909,10 +912,10 @@ static int push_leaf_left(struct ctree_root *root, struct ctree_path *path, push_space = right->items[i].offset; } - wret = write_tree_block(root, t); + wret = dirty_tree_block(root, t); if (wret) ret = wret; - wret = write_tree_block(root, right_buf); + wret = dirty_tree_block(root, right_buf); if (wret) ret = wret; @@ -1019,10 +1022,10 @@ static int split_leaf(struct ctree_root *root, struct ctree_path *path, right_buffer->blocknr, path->slots[1] + 1, 1); if (wret) ret = wret; - wret = write_tree_block(root, right_buffer); + wret = dirty_tree_block(root, right_buffer); if (wret) ret = wret; - wret = write_tree_block(root, l_buf); + wret = dirty_tree_block(root, l_buf); if (wret) ret = wret; @@ -1062,12 +1065,14 @@ int insert_item(struct ctree_root *root, struct key *key, ret = search_slot(root, key, &path, data_size); if (ret == 0) { release_path(root, &path); - return -EEXIST; - } - if (ret < 0) { - release_path(root, &path); + ret = -EEXIST; + wret = commit_transaction(root); + if (wret) + ret = wret; return ret; } + if (ret < 0) + goto out; slot_orig = path.slots[0]; leaf_buf = path.nodes[0]; @@ -1113,14 +1118,18 @@ int insert_item(struct ctree_root *root, struct key *key, if (slot == 0) ret = fixup_low_keys(root, &path, key, 1); - wret = write_tree_block(root, leaf_buf); + wret = dirty_tree_block(root, leaf_buf); if (wret) ret = wret; if (leaf_free_space(leaf) < 0) BUG(); check_leaf(&path, 0); +out: release_path(root, &path); + wret = commit_transaction(root); + if (wret) + ret = wret; return ret; } @@ -1160,7 +1169,7 @@ static int del_ptr(struct ctree_root *root, struct ctree_path *path, int level, if (wret) ret = wret; } - wret = write_tree_block(root, parent); + wret = dirty_tree_block(root, parent); if (wret) ret = wret; return ret; @@ -1203,8 +1212,9 @@ int del_item(struct ctree_root *root, struct ctree_path *path) if (leaf->header.nritems == 0) { if (leaf_buf == root->node) { leaf->header.flags = node_level(0); - write_tree_block(root, leaf_buf); + dirty_tree_block(root, leaf_buf); } else { + clean_tree_block(root, leaf_buf); wret = del_ptr(root, path, 1, path->slots[1]); if (wret) ret = wret; @@ -1220,7 +1230,7 @@ int del_item(struct ctree_root *root, struct ctree_path *path) if (wret) ret = wret; } - wret = write_tree_block(root, leaf_buf); + wret = dirty_tree_block(root, leaf_buf); if (wret) ret = wret; @@ -1242,6 +1252,7 @@ int del_item(struct ctree_root *root, struct ctree_path *path) } if (leaf->header.nritems == 0) { u64 blocknr = leaf_buf->blocknr; + clean_tree_block(root, leaf_buf); wret = del_ptr(root, path, 1, slot); if (wret) ret = wret; @@ -1254,6 +1265,9 @@ int del_item(struct ctree_root *root, struct ctree_path *path) } } } + wret = commit_transaction(root); + if (wret) + ret = wret; return ret; } diff --git a/fs/btrfs/ctree.h b/fs/btrfs/ctree.h index 18daccd84535..6b4dabd47698 100644 --- a/fs/btrfs/ctree.h +++ b/fs/btrfs/ctree.h @@ -1,6 +1,8 @@ #ifndef __CTREE__ #define __CTREE__ +#include "list.h" + #define CTREE_BLOCKSIZE 1024 /* @@ -53,6 +55,9 @@ struct ctree_root { struct key current_insert; int fp; struct radix_tree_root cache_radix; + struct list_head trans; + struct list_head cache; + int cache_size; }; /* diff --git a/fs/btrfs/disk-io.c b/fs/btrfs/disk-io.c index c42dc72706bf..656ace6147a8 100644 --- a/fs/btrfs/disk-io.c +++ b/fs/btrfs/disk-io.c @@ -11,6 +11,8 @@ #include "disk-io.h" static int allocated_blocks = 0; +int cache_size = 0; +int cache_max = 10000; static int check_tree_block(struct ctree_root *root, struct tree_buffer *buf) { @@ -21,6 +23,25 @@ static int check_tree_block(struct ctree_root *root, struct tree_buffer *buf) return 0; } +static int free_some_buffers(struct ctree_root *root) +{ + struct list_head *node, *next; + struct tree_buffer *b; + if (root->cache_size < cache_max) + return 0; + list_for_each_safe(node, next, &root->cache) { + b = list_entry(node, struct tree_buffer, cache); + if (b->count == 1) { + BUG_ON(!list_empty(&b->dirty)); + list_del_init(&b->cache); + tree_block_release(root, b); + if (root->cache_size < cache_max) + return 0; + } + } + return 0; +} + struct tree_buffer *alloc_tree_block(struct ctree_root *root, u64 blocknr) { struct tree_buffer *buf; @@ -30,10 +51,14 @@ struct tree_buffer *alloc_tree_block(struct ctree_root *root, u64 blocknr) return buf; allocated_blocks++; buf->blocknr = blocknr; - buf->count = 1; + buf->count = 2; + INIT_LIST_HEAD(&buf->dirty); + free_some_buffers(root); radix_tree_preload(GFP_KERNEL); ret = radix_tree_insert(&root->cache_radix, blocknr, buf); radix_tree_preload_end(); + list_add_tail(&buf->cache, &root->cache); + root->cache_size++; if (ret) { free(buf); return NULL; @@ -57,7 +82,6 @@ struct tree_buffer *find_tree_block(struct ctree_root *root, u64 blocknr) return buf; } - struct tree_buffer *read_tree_block(struct ctree_root *root, u64 blocknr) { loff_t offset = blocknr * CTREE_BLOCKSIZE; @@ -82,6 +106,24 @@ struct tree_buffer *read_tree_block(struct ctree_root *root, u64 blocknr) return buf; } +int dirty_tree_block(struct ctree_root *root, struct tree_buffer *buf) +{ + if (!list_empty(&buf->dirty)) + return 0; + list_add_tail(&buf->dirty, &root->trans); + buf->count++; + return 0; +} + +int clean_tree_block(struct ctree_root *root, struct tree_buffer *buf) +{ + if (!list_empty(&buf->dirty)) { + list_del_init(&buf->dirty); + tree_block_release(root, buf); + } + return 0; +} + int write_tree_block(struct ctree_root *root, struct tree_buffer *buf) { u64 blocknr = buf->blocknr; @@ -96,9 +138,37 @@ int write_tree_block(struct ctree_root *root, struct tree_buffer *buf) return 0; } +static int __commit_transaction(struct ctree_root *root) +{ + struct tree_buffer *b; + int ret = 0; + int wret; + while(!list_empty(&root->trans)) { + b = list_entry(root->trans.next, struct tree_buffer, dirty); + list_del_init(&b->dirty); + wret = write_tree_block(root, b); + if (wret) + ret = wret; + tree_block_release(root, b); + } + return ret; +} + +int commit_transaction(struct ctree_root *root) +{ + int ret; + ret = __commit_transaction(root); + if (!ret && root != root->extent_root) + ret = __commit_transaction(root->extent_root); + BUG_ON(ret); + return ret; +} + static int __setup_root(struct ctree_root *root, struct ctree_root *extent_root, struct ctree_root_info *info, int fp) { + INIT_LIST_HEAD(&root->trans); + INIT_LIST_HEAD(&root->cache); root->fp = fp; root->node = NULL; root->node = read_tree_block(root, info->tree_root); @@ -157,8 +227,23 @@ int write_ctree_super(struct ctree_root *root, struct ctree_super_block *s) return 0; } +static int drop_cache(struct ctree_root *root) +{ + while(!list_empty(&root->cache)) { + struct tree_buffer *b = list_entry(root->cache.next, + struct tree_buffer, cache); + list_del_init(&b->cache); + tree_block_release(root, b); + } + return 0; +} int close_ctree(struct ctree_root *root) { + drop_cache(root->extent_root); + drop_cache(root); + BUG_ON(!list_empty(&root->trans)); + BUG_ON(!list_empty(&root->extent_root->trans)); + close(root->fp); if (root->node) tree_block_release(root, root->node); @@ -182,6 +267,8 @@ void tree_block_release(struct ctree_root *root, struct tree_buffer *buf) free(buf); BUG_ON(allocated_blocks == 0); allocated_blocks--; + BUG_ON(root->cache_size == 0); + root->cache_size--; } } diff --git a/fs/btrfs/disk-io.h b/fs/btrfs/disk-io.h index 2729b757ddc1..b5dee2fae4da 100644 --- a/fs/btrfs/disk-io.h +++ b/fs/btrfs/disk-io.h @@ -1,5 +1,6 @@ #ifndef __DISKIO__ #define __DISKIO__ +#include "list.h" struct tree_buffer { u64 blocknr; @@ -8,11 +9,16 @@ struct tree_buffer { struct node node; struct leaf leaf; }; + struct list_head dirty; + struct list_head cache; }; struct tree_buffer *read_tree_block(struct ctree_root *root, u64 blocknr); struct tree_buffer *find_tree_block(struct ctree_root *root, u64 blocknr); int write_tree_block(struct ctree_root *root, struct tree_buffer *buf); +int dirty_tree_block(struct ctree_root *root, struct tree_buffer *buf); +int clean_tree_block(struct ctree_root *root, struct tree_buffer *buf); +int commit_transaction(struct ctree_root *root); struct ctree_root *open_ctree(char *filename, struct ctree_super_block *s); int close_ctree(struct ctree_root *root); void tree_block_release(struct ctree_root *root, struct tree_buffer *buf); diff --git a/fs/btrfs/list.h b/fs/btrfs/list.h new file mode 100644 index 000000000000..1aafafb13370 --- /dev/null +++ b/fs/btrfs/list.h @@ -0,0 +1,418 @@ +#ifndef _LINUX_LIST_H +#define _LINUX_LIST_H + +#define LIST_POISON1 ((void *) 0x00100100) +#define LIST_POISON2 ((void *) 0x00200200) + +/* + * Simple doubly linked list implementation. + * + * Some of the internal functions ("__xxx") are useful when + * manipulating whole lists rather than single entries, as + * sometimes we already know the next/prev entries and we can + * generate better code by using them directly rather than + * using the generic single-entry routines. + */ + +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) + +static inline void INIT_LIST_HEAD(struct list_head *list) +{ + list->next = list; + list->prev = list; +} + +/* + * 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) +{ + next->prev = new; + new->next = next; + new->prev = prev; + 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 + * @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. + */ +#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 + + +/** + * list_add_tail - add a new entry + * @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. + */ +static inline void list_add_tail(struct list_head *new, struct list_head *head) +{ + __list_add(new, head->prev, head); +} + +/* + * Delete a list entry by making the prev/next entries + * point to each other. + * + * This is only for internal list manipulation where we know + * the prev/next entries already! + */ +static inline void __list_del(struct list_head * prev, struct list_head * next) +{ + next->prev = prev; + prev->next = 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. + */ +#ifndef CONFIG_DEBUG_LIST +static inline void list_del(struct list_head *entry) +{ + __list_del(entry->prev, entry->next); + 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 + * @old : the element to be replaced + * @new : the new element to insert + * Note: if 'old' was empty, it will be overwritten. + */ +static inline void list_replace(struct list_head *old, + struct list_head *new) +{ + new->next = old->next; + new->next->prev = new; + new->prev = old->prev; + new->prev->next = new; +} + +static inline void list_replace_init(struct list_head *old, + struct list_head *new) +{ + list_replace(old, new); + INIT_LIST_HEAD(old); +} +/** + * 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); + INIT_LIST_HEAD(entry); +} + +/** + * list_move - delete from one list and add as another's head + * @list: the entry to move + * @head: the head that will precede our entry + */ +static inline void list_move(struct list_head *list, struct list_head *head) +{ + __list_del(list->prev, list->next); + list_add(list, head); +} + +/** + * list_move_tail - delete from one list and add as another's tail + * @list: the entry to move + * @head: the head that will follow our entry + */ +static inline void list_move_tail(struct list_head *list, + struct list_head *head) +{ + __list_del(list->prev, list->next); + list_add_tail(list, head); +} + +/** + * list_is_last - tests whether @list is the last entry in list @head + * @list: the entry to test + * @head: the head of the list + */ +static inline int list_is_last(const struct list_head *list, + const struct list_head *head) +{ + return list->next == head; +} + +/** + * list_empty - tests whether a list is empty + * @head: the list to test. + */ +static inline int list_empty(const struct list_head *head) +{ + return head->next == head; +} + +/** + * list_empty_careful - tests whether a list is empty and not being modified + * @head: the list to test + * + * Description: + * tests whether a list is empty _and_ checks that no other CPU might be + * in the process of modifying either member (next or prev) + * + * NOTE: using list_empty_careful() without synchronization + * can only be safe if the only activity that can happen + * to the list entry is list_del_init(). Eg. it cannot be used + * if another CPU could re-list_add() it. + */ +static inline int list_empty_careful(const struct list_head *head) +{ + struct list_head *next = head->next; + return (next == head) && (next == head->prev); +} + +static inline void __list_splice(struct list_head *list, + struct list_head *head) +{ + struct list_head *first = list->next; + struct list_head *last = list->prev; + struct list_head *at = head->next; + + first->prev = head; + head->next = first; + + last->next = at; + at->prev = last; +} + +/** + * list_splice - join two lists + * @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) +{ + if (!list_empty(list)) + __list_splice(list, head); +} + +/** + * list_splice_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. + * + * The list at @list is reinitialised + */ +static inline void list_splice_init(struct list_head *list, + struct list_head *head) +{ + if (!list_empty(list)) { + __list_splice(list, head); + INIT_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. + */ +#define list_entry(ptr, type, member) \ + container_of(ptr, type, member) + +/** + * list_for_each - iterate over a list + * @pos: the &struct list_head to use as a loop cursor. + * @head: the head for your list. + */ +#define list_for_each(pos, head) \ + for (pos = (head)->next; prefetch(pos->next), pos != (head); \ + pos = pos->next) + +/** + * __list_for_each - iterate 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. + */ +#define __list_for_each(pos, head) \ + for (pos = (head)->next; pos != (head); pos = pos->next) + +/** + * list_for_each_prev - iterate over a list backwards + * @pos: the &struct list_head to use as a loop cursor. + * @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) + +/** + * list_for_each_safe - iterate over a list 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_safe(pos, n, head) \ + for (pos = (head)->next, n = pos->next; pos != (head); \ + pos = n, n = pos->next) + +/** + * 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. + */ +#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)) + +/** + * 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. + */ +#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)) + +/** + * 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. + * + * Prepares a pos entry for use as a start point in list_for_each_entry_continue. + */ +#define list_prepare_entry(pos, head, member) \ + ((pos) ? : list_entry(head, typeof(*pos), member)) + +/** + * 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. + * + * 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)) + +/** + * 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. + * + * 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)) + +/** + * 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. + */ +#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); \ + &pos->member != (head); \ + pos = n, n = list_entry(n->member.next, typeof(*n), member)) + +/** + * list_for_each_entry_safe_continue + * @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. + * + * 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); \ + &pos->member != (head); \ + pos = n, n = list_entry(n->member.next, typeof(*n), member)) + +/** + * list_for_each_entry_safe_from + * @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. + * + * 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); \ + &pos->member != (head); \ + pos = n, n = list_entry(n->member.next, typeof(*n), member)) + +/** + * list_for_each_entry_safe_reverse + * @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. + * + * 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); \ + &pos->member != (head); \ + pos = n, n = list_entry(n->member.prev, typeof(*n), member)) + +#endif