From f5baaf48e3e82b1caf9f5cd1207d4d6feba3a2e5 Mon Sep 17 00:00:00 2001 From: Thomas Bertschinger Date: Mon, 15 Jan 2024 23:41:02 -0700 Subject: move Rust sources to top level, C sources into c_src This moves the Rust sources out of rust_src/ and into the top level. Running the bcachefs executable out of the development tree is now: $ ./target/release/bcachefs command or $ cargo run --profile release -- command instead of "./bcachefs command". Building and installing is still: $ make && make install Signed-off-by: Thomas Bertschinger Signed-off-by: Kent Overstreet --- c_src/linux/llist.c | 92 +++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 92 insertions(+) create mode 100644 c_src/linux/llist.c (limited to 'c_src/linux/llist.c') diff --git a/c_src/linux/llist.c b/c_src/linux/llist.c new file mode 100644 index 00000000..611ce488 --- /dev/null +++ b/c_src/linux/llist.c @@ -0,0 +1,92 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * Lock-less NULL terminated single linked list + * + * The basic atomic operation of this list is cmpxchg on long. On + * architectures that don't have NMI-safe cmpxchg implementation, the + * list can NOT be used in NMI handlers. So code that uses the list in + * an NMI handler should depend on CONFIG_ARCH_HAVE_NMI_SAFE_CMPXCHG. + * + * Copyright 2010,2011 Intel Corp. + * Author: Huang Ying + */ +#include +#include +#include + + +/** + * llist_add_batch - add several linked entries in batch + * @new_first: first entry in batch to be added + * @new_last: last entry in batch to be added + * @head: the head for your lock-less list + * + * Return whether list is empty before adding. + */ +bool llist_add_batch(struct llist_node *new_first, struct llist_node *new_last, + struct llist_head *head) +{ + struct llist_node *first; + + do { + new_last->next = first = READ_ONCE(head->first); + } while (cmpxchg(&head->first, first, new_first) != first); + + return !first; +} +EXPORT_SYMBOL_GPL(llist_add_batch); + +/** + * llist_del_first - delete the first entry of lock-less list + * @head: the head for your lock-less list + * + * If list is empty, return NULL, otherwise, return the first entry + * deleted, this is the newest added one. + * + * Only one llist_del_first user can be used simultaneously with + * multiple llist_add users without lock. Because otherwise + * llist_del_first, llist_add, llist_add (or llist_del_all, llist_add, + * llist_add) sequence in another user may change @head->first->next, + * but keep @head->first. If multiple consumers are needed, please + * use llist_del_all or use lock between consumers. + */ +struct llist_node *llist_del_first(struct llist_head *head) +{ + struct llist_node *entry, *old_entry, *next; + + entry = smp_load_acquire(&head->first); + for (;;) { + if (entry == NULL) + return NULL; + old_entry = entry; + next = READ_ONCE(entry->next); + entry = cmpxchg(&head->first, old_entry, next); + if (entry == old_entry) + break; + } + + return entry; +} +EXPORT_SYMBOL_GPL(llist_del_first); + +/** + * llist_reverse_order - reverse order of a llist chain + * @head: first item of the list to be reversed + * + * Reverse the order of a chain of llist entries and return the + * new first entry. + */ +struct llist_node *llist_reverse_order(struct llist_node *head) +{ + struct llist_node *new_head = NULL; + + while (head) { + struct llist_node *tmp = head; + head = head->next; + tmp->next = new_head; + new_head = tmp; + } + + return new_head; +} +EXPORT_SYMBOL_GPL(llist_reverse_order); -- cgit v1.2.3