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Based on 1 normalized pattern(s):

  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 merchantability or
  fitness for a particular purpose see the 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

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-only

has been chosen to replace the boilerplate/reference in 136 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190530000436.384967451@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
8 contributors

Users who have contributed to this file

@yhuang-intel @torvalds @paulgortmaker @utrace @Villemoes @dvyukov @dhowells @akpm00
// 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 <ying.huang@intel.com>
*/
#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;
}
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);