Branch data     Line data    Source code

       1                 :            : /*
       2                 :            :  *  Generic Timer-queue
       3                 :            :  *
       4                 :            :  *  Manages a simple queue of timers, ordered by expiration time.
       5                 :            :  *  Uses rbtrees for quick list adds and expiration.
       6                 :            :  *
       7                 :            :  *  NOTE: All of the following functions need to be serialized
       8                 :            :  *  to avoid races. No locking is done by this library code.
       9                 :            :  *
      10                 :            :  *  This program is free software; you can redistribute it and/or modify
      11                 :            :  *  it under the terms of the GNU General Public License as published by
      12                 :            :  *  the Free Software Foundation; either version 2 of the License, or
      13                 :            :  *  (at your option) any later version.
      14                 :            :  *
      15                 :            :  *  This program is distributed in the hope that it will be useful,
      16                 :            :  *  but WITHOUT ANY WARRANTY; without even the implied warranty of
      17                 :            :  *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
      18                 :            :  *  GNU General Public License for more details.
      19                 :            :  *
      20                 :            :  *  You should have received a copy of the GNU General Public License
      21                 :            :  *  along with this program; if not, write to the Free Software
      22                 :            :  *  Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
      23                 :            :  */
      24                 :            : 
      25                 :            : #include <linux/bug.h>
      26                 :            : #include <linux/timerqueue.h>
      27                 :            : #include <linux/rbtree.h>
      28                 :            : #include <linux/export.h>
      29                 :            : 
      30                 :            : /**
      31                 :            :  * timerqueue_add - Adds timer to timerqueue.
      32                 :            :  *
      33                 :            :  * @head: head of timerqueue
      34                 :            :  * @node: timer node to be added
      35                 :            :  *
      36                 :            :  * Adds the timer node to the timerqueue, sorted by the
      37                 :            :  * node's expires value.
      38                 :            :  */
      39                 :          0 : void timerqueue_add(struct timerqueue_head *head, struct timerqueue_node *node)
      40                 :            : {
      41                 :   12694136 :         struct rb_node **p = &head->head.rb_node;
      42                 :            :         struct rb_node *parent = NULL;
      43                 :            :         struct timerqueue_node  *ptr;
      44                 :            : 
      45                 :            :         /* Make sure we don't add nodes that are already added */
      46 [ -  + ][ #  # ]:   12694136 :         WARN_ON_ONCE(!RB_EMPTY_NODE(&node->node));
                 [ -  + ]
      47                 :            : 
      48         [ +  + ]:   39848960 :         while (*p) {
      49                 :            :                 parent = *p;
      50                 :            :                 ptr = rb_entry(parent, struct timerqueue_node, node);
      51         [ +  + ]:   14468712 :                 if (node->expires.tv64 < ptr->expires.tv64)
      52                 :   14006233 :                         p = &(*p)->rb_left;
      53                 :            :                 else
      54                 :   14468712 :                         p = &(*p)->rb_right;
      55                 :            :         }
      56                 :            :         rb_link_node(&node->node, parent, p);
      57                 :   12686112 :         rb_insert_color(&node->node, &head->head);
      58                 :            : 
      59 [ +  + ][ +  + ]:   12688078 :         if (!head->next || node->expires.tv64 < head->next->expires.tv64)
      60                 :   12284709 :                 head->next = node;
      61                 :   12688078 : }
      62                 :            : EXPORT_SYMBOL_GPL(timerqueue_add);
      63                 :            : 
      64                 :            : /**
      65                 :            :  * timerqueue_del - Removes a timer from the timerqueue.
      66                 :            :  *
      67                 :            :  * @head: head of timerqueue
      68                 :            :  * @node: timer node to be removed
      69                 :            :  *
      70                 :            :  * Removes the timer node from the timerqueue.
      71                 :            :  */
      72                 :          0 : void timerqueue_del(struct timerqueue_head *head, struct timerqueue_node *node)
      73                 :            : {
      74 [ -  + ][ #  # ]:   12691735 :         WARN_ON_ONCE(RB_EMPTY_NODE(&node->node));
                    [ - ]
      75                 :            : 
      76                 :            :         /* update next pointer */
      77         [ +  + ]:   12670723 :         if (head->next == node) {
      78                 :   12457941 :                 struct rb_node *rbn = rb_next(&node->node);
      79                 :            : 
      80                 :   12464009 :                 head->next = rbn ?
      81         [ +  + ]:   25155744 :                         rb_entry(rbn, struct timerqueue_node, node) : NULL;
      82                 :            :         }
      83                 :   12676791 :         rb_erase(&node->node, &head->head);
      84                 :   12682938 :         RB_CLEAR_NODE(&node->node);
      85                 :   12682938 : }
      86                 :            : EXPORT_SYMBOL_GPL(timerqueue_del);
      87                 :            : 
      88                 :            : /**
      89                 :            :  * timerqueue_iterate_next - Returns the timer after the provided timer
      90                 :            :  *
      91                 :            :  * @node: Pointer to a timer.
      92                 :            :  *
      93                 :            :  * Provides the timer that is after the given node. This is used, when
      94                 :            :  * necessary, to iterate through the list of timers in a timer list
      95                 :            :  * without modifying the list.
      96                 :            :  */
      97                 :          0 : struct timerqueue_node *timerqueue_iterate_next(struct timerqueue_node *node)
      98                 :            : {
      99                 :            :         struct rb_node *next;
     100                 :            : 
     101         [ +  - ]:         16 :         if (!node)
     102                 :            :                 return NULL;
     103                 :         16 :         next = rb_next(&node->node);
     104         [ +  + ]:         16 :         if (!next)
     105                 :            :                 return NULL;
     106                 :         14 :         return container_of(next, struct timerqueue_node, node);
     107                 :            : }
     108                 :            : EXPORT_SYMBOL_GPL(timerqueue_iterate_next);