cregit-Linux how code gets into the kernel

Release 4.16 lib/llist.c

Directory: lib
 * 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 <>
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version
 * 2 as published by the Free Software Foundation;
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * GNU General Public License for more details.
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/llist.h>

 * 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; }


Huang Ying4369.35%250.00%
Oleg Nesterov1829.03%125.00%
Mark Rutland11.61%125.00%

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; }


Huang Ying7991.86%266.67%
Dmitriy Vyukov78.14%133.33%

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; }


Christoph Hellwig51100.00%1100.00%


Overall Contributors

Huang Ying14262.56%330.00%
Christoph Hellwig5624.67%110.00%
Oleg Nesterov187.93%110.00%
Dmitriy Vyukov73.08%110.00%
Mark Rutland10.44%110.00%
Ingo Molnar10.44%110.00%
Andrew Morton10.44%110.00%
Paul Gortmaker10.44%110.00%
Directory: lib
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