Eric Lee / smarc-fsl-linux-kernel

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lib/plist.c 2.75 KB
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77ba89c5c   Ingo Molnar   [PATCH] pi-futex:... 
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  /*
   * lib/plist.c
   *
   * Descending-priority-sorted double-linked list
   *
   * (C) 2002-2003 Intel Corp
   * Inaky Perez-Gonzalez <inaky.perez-gonzalez@intel.com>.
   *
   * 2001-2005 (c) MontaVista Software, Inc.
   * Daniel Walker <dwalker@mvista.com>
   *
   * (C) 2005 Thomas Gleixner <tglx@linutronix.de>
   *
   * Simplifications of the original code by
   * Oleg Nesterov <oleg@tv-sign.ru>
   *
   * Licensed under the FSF's GNU Public License v2 or later.
   *
   * Based on simple lists (include/linux/list.h).
   *
   * This file contains the add / del functions which are considered to
   * be too large to inline. See include/linux/plist.h for further
   * information.
   */
  
  #include <linux/plist.h>
  #include <linux/spinlock.h>
  
  #ifdef CONFIG_DEBUG_PI_LIST
  
  static void plist_check_prev_next(struct list_head *t, struct list_head *p,
  				  struct list_head *n)
  {
5cd2b459d   Arjan van de Ven   Use WARN() in lib/ 
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  	WARN(n->prev != p || p->next != n,
  			"top: %p, n: %p, p: %p
  "
  			"prev: %p, n: %p, p: %p
  "
  			"next: %p, n: %p, p: %p
  ",
  			 t, t->next, t->prev,
  			p, p->next, p->prev,
  			n, n->next, n->prev);
77ba89c5c   Ingo Molnar   [PATCH] pi-futex:... 
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  }
  
  static void plist_check_list(struct list_head *top)
  {
  	struct list_head *prev = top, *next = top->next;
  
  	plist_check_prev_next(top, prev, next);
  	while (next != top) {
  		prev = next;
  		next = prev->next;
  		plist_check_prev_next(top, prev, next);
  	}
  }
  
  static void plist_check_head(struct plist_head *head)
  {
  	WARN_ON(!head->lock);
  	if (head->lock)
  		WARN_ON_SMP(!spin_is_locked(head->lock));
  	plist_check_list(&head->prio_list);
  	plist_check_list(&head->node_list);
  }
  
  #else
  # define plist_check_head(h)	do { } while (0)
  #endif
  
  /**
   * plist_add - add @node to @head
   *
   * @node:	&struct plist_node pointer
   * @head:	&struct plist_head pointer
   */
  void plist_add(struct plist_node *node, struct plist_head *head)
  {
  	struct plist_node *iter;
  
  	plist_check_head(head);
  	WARN_ON(!plist_node_empty(node));
  
  	list_for_each_entry(iter, &head->prio_list, plist.prio_list) {
  		if (node->prio < iter->prio)
  			goto lt_prio;
  		else if (node->prio == iter->prio) {
  			iter = list_entry(iter->plist.prio_list.next,
  					struct plist_node, plist.prio_list);
  			goto eq_prio;
  		}
  	}
  
  lt_prio:
  	list_add_tail(&node->plist.prio_list, &iter->plist.prio_list);
  eq_prio:
  	list_add_tail(&node->plist.node_list, &iter->plist.node_list);
  
  	plist_check_head(head);
  }
  
  /**
   * plist_del - Remove a @node from plist.
   *
   * @node:	&struct plist_node pointer - entry to be removed
   * @head:	&struct plist_head pointer - list head
   */
  void plist_del(struct plist_node *node, struct plist_head *head)
  {
  	plist_check_head(head);
  
  	if (!list_empty(&node->plist.prio_list)) {
  		struct plist_node *next = plist_first(&node->plist);
  
  		list_move_tail(&next->plist.prio_list, &node->plist.prio_list);
  		list_del_init(&node->plist.prio_list);
  	}
  
  	list_del_init(&node->plist.node_list);
  
  	plist_check_head(head);
  }